DOI: 10.31038/CST.2019443

Abstract

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare type of epithelial renal tumor considered as a low-grade neoplasm by the World Health Organization. Therefore, partial or radical nephrectomy may be curative whether in early stages. Less than a hundred of these tumors have been reported with gross and microscopic features, immunohistochemical profile and clinical findings. Here we report two cases of MTSCC with emphasis on the clinicopathological correlations according to postoperative findings. Both patients underwent a video-assisted resection of the kidney. No recurrence or metastasis was observed during the follow-up.

Keywords

Renal Mucinous Tubular and Spindle cell Carcinoma, Renal Cell Carcinoma, Pathology

Introduction

Mucinous tubular and spindle cell carcinoma (MTSCC) is a histological type of renal carcinoma endorsed as an entity in 2004 by the World Health Organization (WHO) [1]. It accounts for less than 1% of all kidney tumors and shows a higher prevalence in women. Until 2015, there were less than 100 cases reported in the literature [2–6]. MTSCC may be associated with monosomy 1, 4, 6, 8, 13 or 14 and trisomy 7, 11, 16 or 17. Microscopically, the neoplasm is characterized tubular growth pattern of uniform cuboidal cells with eosinophilic cytoplasm which transition to anastomosing spindle cells in a myxoid and bubbly with abundant extracellular mucin stroma [1,2,4–11]. MTSCC is a low malignant potential cancer that rarely relapses or metastasizes [5,12].

We present two cases of mucinous tubular and spindle cell carcinoma diagnosed and treated in a high complexity Brazilian hospital.

Case Presentation

Case One

A 61-year-old, previously healthy woman attended to the urology outpatient clinic due to an incidental image finding. An abdominal CT scan had shown a 2-cm nodular mass in the upper pole of the left kidney. The physical examination was normal. Laboratory studies and renal function tests showed no changes. Video-assisted left radical nephrectomy and perihilar lymphadenectomy were performed. The gross examination revealed a well-circumscribed grayish-white tumor confined to the atrophic kidney (figure 1). No renal vein invasion was detected. Microscopic examination of the mass showed low nuclear grade cells with focally vacuolated eosinophilic cytoplasm and spindle cells organized in long tubular profiles. Some clusters of foamy macrophages were present and extracellular mucin was highlighted by Alcian blue stain (figure 2). No sarcomatoid features were seen. Immunohistochemistry reactions were performed and the cells stained for CK7 and alphamethylacyl-CoA racemase (AMACR) and showed negativity for vimentin and CD10 (table 1). In conclusion, the diagnosis of a mucinous tubular and spindle cell carcinoma was stated. No metastasis was present in the lymph node submitted for evaluation. The patient has been on follow-up for 2 years and had no complaints. Imaging exams have not detected abnormalities.

Figure 1. Gross appearance of MTSCC. The tumor is well-circumcribed with a homogeneous, well-circumscribed grayish-white cut surface. Notice the atrophic parenchima.

Figure 2. Microscopic appearance of MTSCC.

Case Two

A 71-year-old woman was admitted in the Emergency Room. She has had moderate left flank pain that radiated to the chest and left leg over the past 6 months. On a scale of 1 to 10, the pain was 6. She also complained about dysuria. No weight-loss had been noticed. She had a long-term smoking history and had received irregular treatment for systemic arterial hypertension. On physical examination, her temperature was normal and blood pressure was 140/90 mmHg. There was pain on deep left flank palpation. An abdominal ultrasound showed a 4.7-cm nodular mass suspected of malignancy in the left kidney. A partial video-assisted nephrectomy was performed. On the specimen’s gross examination, a pushing border nodular tumor was found. It measured up to 3.8 cm in diameter and was yellowish. No renal vein invasion was detected. Microscopic examination of the tumor revealed Fuhrman grade 1 nucleus low cuboidal and spindle cells arranged in tubular or cord-like growth pattern (figure 3). Stroma was myxoid and bubbly (figure 4). No sarcomatoid features were present. Immunohistochemistry reactions were performed and the cells stained for CK7 and AMACR and vimentin (table 1). The pathological findings sustained the diagnosis of a mucinous tubular and spindle cell carcinoma. The patient has been on annual follow-up for 5 years and imaging exams have not detected signs of relapsed disease or metastasis.

Figure 3. Microscopic features of MTSCC.

Figure 4. Stroma microscopic findings.

Table 1. Immunophenotypic Profile of Renal Mucinous Tubular and Spindle Cell Carcinoma

VIM, vimentin; HMWCK, high-molecular weight cytokeratin; AMACR, alpha-methyl CoA racemase

Discussion

We present two cases of mucinous tubular and spindle cell renal cell carcinoma affecting two elderly women. MTSCC has a wide age distribution which ranges between 13 to 82 years old and an average of 53 years old. There are a female predominance and a 1: 4 man to women ratio [4,6,13,14,15].

MTSCC is a renal epithelial neoplasm characterized by tubular formations merging with bland spindle cells and a myxoid stroma [5,16]. Proper histological classification is essential for a better understanding of this tumor which has already been characterized and distinguished from other renal cell carcinomas (RCC) through immunohistochemical and cytogenetic studies [17]. The vast majority of these renal neoplasms are low grade [13]. However, sarcomatoid differentiation implies in a deleterious prognosis and requires a closer clinical and radiological follow-up [18]. Clinically, most patients present with asymptomatic masses found accidentally by ultrasound [19]. Even though, some MTSCC can manifest as flank pain, hematuria, abdominal mass and systemic repercussions such as fever, anorexia and weight loss [4,15,18 20].

On gross examination, mostly occur as a solid mass in the renal cortex and are partially encapsulated. The cut surface is usually shiny, bulging and mucoid and shows pale, grey or homogenous tan colors [5,6,14].

Microscopic sections feature a renal epithelial neoplasm with variable components of tubular or cord-like growth architecture, spindle cell areas and extracellular basophilic mucinous stroma [6,10,13]. Necrosis, mucin-poor stroma, cellular pleomorphism, and high nuclear grade are uncommon. Hardly, MTSCC can present aggressive local growth and spread distant metastasis to liver and retroperitoneal lymph nodes [6,14,20]. Based on extracellular mucin, MTSCC splits into two categories: classic (abundant extracellular mucin stroma) and mucin-poor (little or no extracellular mucin stroma). Mucinous stroma stains blueish to Alcian blue and colloidal iron [4,14].

Immunohistochemical studies confirm that both cuboidal and spindle cells are positive for PAX2/8, epithelial membrane antigen (EMA), low molecular weight cytokeratins (CK8/18, CK19, and CK7), E-cadherin and AMACR. Vimentin and high molecular weight cytokeratin (34BE12) staining show variable expressions. CD10, CD15, and RCC marker are usually positive in other RCC variants and frequently negative in MTSCC [4–6,8,9,14,15,18]. Immunohistochemical characteristics of both cases we reported are summarized in table 1.

Classic MTSCC offers no diagnosis challenges. On the other hand, mucin-poor MTSCC is often misdiagnosed as mesenchymal neoplasms (e.g. inflammatory myofibroblastic tumor) which tend to present elongated nuclei, distinct fascicular arrangement and rarely label cytokeratins strongly. Papillary RCC is another differential diagnosis to be considered which usually has round cells, variable atypia and predominant tubulopapillary pattern and no extracellular mucin. Immunocytochemistry is usually useless [13,15,21]. Classical morphology and complete surgical excision correlate with favorable prognosis. Nevertheless, sarcomatoid features must be reported because they may indicate an aggressive course [5,6,10,15]. A close follow-up is recommended for all MTSCC [5,6].

Conclusion

In summary, we report two cases of mucinous tubular and spindle cell renal cell carcinoma. We consider MTSCC to be a low-grade carcinoma. Although the follow-up for our two cases was favorable, precaution is warned given the small number of reported MTSCC and the fact that some have metastasized. The current study also highlights that additional clinicopathological expertise with these renal tumors is necessary to comprehend their biological behavior.

Authorship

Queiroz, GA and Silva, WNT collected data, reviewed the literature, analyzed the data and wrote the manuscript; Sudo, RSL and Oliveira, TJ participated in the literature review and helped to write the manuscript; Dornelas, BC designed the project, collected data, reviewed the literature and revised the manuscript. All authors have read and approved the final manuscript.

Funding information: The authors declare that they have no funding

Units of Measurement: Measurements of length: centimeter (cm)

Abbreviations & Symbols

MTSCC: mucinous tubular and spindle cell carcinoma

WHO: World Health Organization

RCC: renal cell carcinomas

VIM: vimentin

HMWCK: high-molecular weight cytokeratin

AMACR: alpha-methyl CoA racemase

References

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DOI: 10.31038/CST.2019442

Abstract

Prostate cancer metastases are commonly seen in the skeleton, lymph nodes, lungs, or liver, and are associated with a poor five-year survival rate. Renal pelvis and ureteral metastasis are exceedingly uncommon and can present with obstructive symptoms or as an asymptomatic mass on imaging. We report the case of a 60-year-old patient who was initially diagnosed with prostate adenocarcinoma and experienced eventual metastasis to the right renal pelvis and proximal ureter. Following the diagnosis, he was started on docetaxel and pembrolizumab as part of a clinical trial protocol. A high index of suspicion and thorough metastatic work-up is necessary when patients with prostate cancer present with symptoms of obstructive uropathy or new visceral disease is identified.

Key Words

Prostate Cancer, Hydronephrosis, Ureteral metastasis, Renal Pelvis Metastasis, Metastatic Prostate Cancer

Introduction

Prostate adenocarcinoma (PCa) is currently the second most common cause of cancer in men worldwide. In 2019, there were an estimated 174,650 new cases and 31,620 deaths attributed to prostate cancer in the United States [1]. Although the incidence of low-risk prostate cancer between 2007 and 2013 decreased to 37% less than that of 2004, the annual incidence of metastatic prostate cancer (mPCa) during the same period increased by 72% [2]. At diagnosis, 12% of prostate cancer cases have spread to regional lymph nodes, and 5% have distant metastases. Distant spread portends a poor prognosis, with a 5-year relative survival rate of only 29.8% [3]. Classically, prostate cancer is associated with skeletal metastases. Visceral organ involvement is most often seen in the lungs and liver, with other sites quite rare. In this light, we report the case of a patient who was diagnosed with prostate adenocarcinoma, with eventual metastasis to the right renal pelvis and proximal ureter.

Case Report

The patient is a 60-year-old African American man who was found to have an elevated prostate specific antigen (PSA) of 34.0 ng/mL during routine screening by his primary care physician in early 2009. He did not follow-up until re-screening in 2011, at which time he was found to have a PSA of 315.86. Transrectal ultrasound guided prostate biopsy at that time revealed high-risk adenocarcinoma of the prostate with a Gleason score 4 + 5 = 9 involving 40% of the submitted tissue (Figure 1). Metastatic workup consisting of bone scan showed a questionable area in the cervical spine, but follow-up magnetic resonance imaging (MRI) revealed simply degenerative disk disease in the cervical spine and no evidence of metastatic disease. He was then started on androgen deprivation therapy with leuprolide and bicalutamide with a PSA nadir of 0.63 ng/mL in April 2012. Later that year, his PSA values began to rise, but restaging scans remained negative for metastatic disease. At this time, he received external beam radiation therapy to the pelvis, prostate, and seminal vesicles to a total dose of 7920 cGy over 4 months, completing in March 2013. Despite an initial improvement, he experienced subsequent increase in his PSA, and antiandrogen withdrawal (bicalutamide) was performed at the end of 2013.

Figure 1. Prostate needle core biopsy with prostatic adenocarcinoma, Gleason score 4+5=9, involving 40% of submitted tissue (original magnification x200)

In 2014, the patient presented to the ED with gross hematuria. Computed tomography (CT) urogram was unremarkable. On cystoscopy, the bladder mucosa showed changes consistent with radiation cystitis. At this time, his PSA was 0.78 ng/mL, where it remained stable for approximately 2 years. When it rose to a level of 7.19 ng/mL in January 2017, he was started on enzalutamide. On restaging scan in July 2017, a new right renal pelvis mass was identified, which was confirmed with a subsequent MRI of the abdomen in September. The 3.7 cm enhancing mass was seen in the right renal pelvis extending and obstructing the proximal right ureter, causing severe right hydronephrosis. A contiguous 1.6 cm nodule was also seen along the inferior aspect of the right renal pelvis (Figure 2). A nephrostomy tube was placed to relieve the hydronephrosis. Ureteroscopic biopsy of this lesion was attempted in early October 2017 but was not feasible due to stenosis of his right distal ureter, likely due to his prior external beam radiation. A right ureteral stent was placed at that time with the goal of removing his nephrostomy tube. He underwent CT guided fine needle aspiration and core biopsy of this right renal pelvis mass on 10/30/17. The biopsy showed poorly differentiated metastatic prostate adenocarcinoma (Figure 3). By immunohistochemistry, the tumor cells are positive for NKX3.1, PSA and Prostein, while negative for CK7, CK20, PAX8 and GATA3, consistent with mPCa. Following this diagnosis, he was started on docetaxel and pembrolizumab as part of a clinical trial.

Figure 2. Transverse (A) and coronal (B) images of MRI of the abdomen revealing the right renal pelvis mass causing severe hydronephrosis of the right kidney

Figure 3. (A) Right renal pelvis core needle biopsy showing mPCa on H&E, confirmed by NKX3.1 immuno histochemical stain (B) (original magnification x200)

Discussion

In 74,826 patients with metastatic prostate cancer from 1998 to 2010, the most common sites of spread were to the bone (84%), distant lymph nodes (10.6%), liver (10.2%), and thorax (9.1%) [4]. At a more local level, prostate cancer can also invade the seminal vesicles, bladder, and rectum, in addition to regional lymph nodes [5]. Renal pelvis and ureteral metastases are quite rare, with less than 50 such cases reported in the literature [6]. The low incidence is hypothesized to be a result of the lymphatic circulation of the ureter is segmental and drains diagonally or transversely, with no continuous longitudinal lymphatic network draining directly from the prostatic region [7]. More commonly, metastases to the ureters and renal pelvis originate from breast, gastric, or colon cancer [8].

Before the development of advanced imaging and ureteroscopic techniques, ureteral metastases were most often incidental findings on autopsies [9]. Approximately 85% of these ureteral metastases were asymptomatic at diagnosis and most of them are identified in patients with known prostate cancer [10]. In symptomatic patients, the symptoms mimic other renal pelvic and ureteral tumors, with flank pain and hematuria being the most common. The diagnosis can be made via a traditional ureteroscopic evaluation and biopsy [11]. However, this was not feasible in our patient due to ureteral stenosis. Zhang et al. reported their experience with a similar patient having a distal ureteral stricture which prevented a biopsy done via an endoscopic approach [12]. Although a nephroureterectomy was performed in that patient given the concern for urothelial carcinoma of the ureter, the final pathology revealed mPCa. This highlights the importance of establishing a pathologic diagnosis from a biopsy when there is a possibility that a ureteral lesion is of metastatic origin.

The low incidence of mPCa to the ureters and renal pelvis is hypothesized to be a result of the lymphatic circulation of the ureter, which is segmental and drains diagonally or transversely, with no continuous longitudinal lymphatic network draining directly from the prostatic region.⁷ One proposed mechanism for metastasis involves dissemination of malignant cells to the retroperitoneal lymph nodes near the ureter via the periureteral lymphatic pathway [13]. Yonneau et al. further added that the secondary tumor develops from the adventitia prior to invading the ureteric wall [14]. This differs from the proposed mechanism for prostate cancer metastasis to the renal parenchyma, which is attributed to the spread of tumor emboli in the arterial system to the highly vascular kidneys [5]. Singh et al. mention preceding genitourinary tract instrumentation, including urethral catheterization or cystoureteroscopy, as a risk factor for urothelial seeding [15]. Thus, in patients with pCa and clinical signs such as hydronephrosis or symptoms such as flank pain and hematuria, workup for ureteral metastases may be warranted, especially when there is a history of prior urinary tract instrumentation.

In 2004, Milbank et al. described percutaneous resection to manage symptomatic obstruction from mPCa to the renal pelvis in two patients, a technique that resulted in complete relief of symptoms and obstruction [16]. Open operative intervention is not ideal in a patient population with metastatic disease, and angioinfarction is of unlikely benefit as these lesions are not of a parenchymal origin. Chronic internal stenting or nephrostomy tube placement are viable low-risk options, but they can compromise patients quality of life [17]. While the two patients in Milbank’s report ultimately died of mPCa, percutaneous resection may be a worthwhile consideration when performed by experienced surgeons in carefully selected patients.

Despite progression to castration resistance, a subset of patients may not harbor detectable metastasis by traditional imaging techniques, and therefore are categorized as having non-metastatic castration resistant prostate cancer (M0 CRPC). This was initially the case with our patient. Similar patients with M0 CRPC are at high risk for progression to metastatic disease, as 15% to 33% develop metastasis within 2 years [18]. In 2017, the American Society of Clinical Oncology issued a provisional clinical opinion that stated patients with radiographic evidence of metastases and minimal symptoms should be offered enzalutamide or abiraterone plus prednisone after weighing potential harms, benefits, costs, and patient preferences [19]. However, newer positron emission tomography (PET) imaging-based tracers were not used in these studies, and it is possible that a subset of these men had metastases that were not detectable by the limits of conventional CT imaging and nuclear bone scan [18]. This may have been the case in our patient, who eventually developed metastasis to the renal pelvis within a year of starting enzalutamide.

Conclusions

A small portion of men with advanced prostate cancer may develop metastasis to atypical sites, such as the renal pelvis and ureter. Thus, oncologists must have a high index of suspicion when prostate cancer patients are found to have ureteral/renal pelvis masses causing hydronephrosis. Biopsy of the metastatic site should be considered if extirpative surgery, or a change in hormonal/systemic therapy, is being considered [20]. While a considerable amount of research has been devoted to the treatment of mPCa, the response of these treatments in the setting of metastatic disease to the renal pelvis and ureter is not clear.

Funding: This work is supported by a grant from the National Cancer Institute (P30CA072720).

Disclosure: EA Singer receives research support from Astellas/Medivation.

References

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DOI: 10.31038/CST.2019441

Abstract

Nucleolin, a major protein of the nucleolus which is required for cell proliferation is the subject of numerous studies in the field of oncology. Many studies suggest that the level of expression of nucleolin and its cellular localization could be an indication of the clinical outcome in several cancers. Quite logically for a protein required for the cancer cells to increased protein synthesis, a correlation between the high level of nucleolin expression and the poor prognosis of the patients is often reported. Unexpectedly, in several studies it was also found that a low nucleolin expression could be also associated with an unfavorable prognosis. In these commentary I discuss these studies and the possible implications for using nucleolin as a prognostic marker in oncology.

Keywords

Nucleolin, Cancer, Prognostic Marker

Nucleolin, an abundant multifunctional protein with multiple cellular localization

Nucleolin was first described as an abundant phopho-nucleolar protein [1]. The protein is heavily modified post-translationally [2] and can interact with numerous proteins [3] and nucleic acids [4, 5]. The nucleolar localization of nucleolin suggested that it could be involved in some aspects of ribosome biogenesis as the nucleolar structures are the sites of transcription of the pre-ribosomal RNA and of its assembly with ribosomal proteins to form the pre-ribosomes that are then exported in the cell cytoplasm for the mRNA translation. Indeed, it was shown that nucleolin expression was required for the formation of functional nucleolar structure [6, 7]. Nucleolin is required for RNA polymerase I transcription [8, 9] probably through its chaperone activity that facilitates transcription of chromatin [10–12]. It has been suggested that the transient interaction of nucleolin with the pre-rRNA during transcription might be involved in the correct folding of the long pre-RNA which is required for the processing in mature ribosomal RNA [13–17] but it remains to be demonstrated if the RNA binding specificity of nucleolin towards pre-rRNA is important as deletion of the RNA binding domains responsible for this specificity do not seems to be crucial for the vital function of nucleolin [7]. By analogy to this co-transcriptional role of nucleolin in pre-rRNA maturation and assembly with proteins, it has been recently suggested that acetylated nucleolin could also be involved in the assembly of pre-catalytic spliceosomes and in splicing reaction [18, 19]. Several reports suggest also that nucleolin could be involved in the regulation of transcription of some ANP polymerase II genes [20–24]. Whether there is a functional link between this RNAPII regulation and the implication in the co-transcriptional splicing of some pre-mRNA remains to be determined. In addition to this fundamental role in the regulation of gene expression, there has been a renewed interest in the study of this protein because it has been discovered that nucleolin is also present on the cell surface. Initially described as a HIV gp120 V3 loop binding protein which could be involved in the binding of HIV particles to CD4(+) cells [25, 26], it was then suggested that cell surface nucleolin could be a receptor for diverse ligands [27–29].

Cell surface nucleolin was then described as a marker of endothelial cells in angiogenic blood [30] and this specific localization was associated with cancer cells [31–36].Whether the localization of nucleolin on the cell surface is specific to the cancerous nature of the cell or is the result of a high proliferation rate of these cells remains to be determined. One major difficulty to study the function of cell surface nucleolin and its link with cancer cells is that the detection of cell surface nucleolin is difficult. Initial studies were performed by incubating cells with a monoclonal antibody (mAb D3) at room temperature before paraformaldehyde (PFA) fixation [37]. The beautiful images showing a regular localization of nucleolin on the surface of HeLa cells are very difficult to reproduce with other anti-nucleolin antibodies. Nevertheless, in other studies, immunoelectron microscopy [38] or cell fractionation [37, 39] confirmed the presence of nucleolin on the cell surface.

Is Nucleolin expression a marker for cancer cells ?

Since several decades, it is known that cells that have a high proliferation rate express more nucleolar proteins (including nucleolin) as reflected by the silver staining method (AgNOR) [40]. It is therefore not surprising that, in general, cancer cells are also characterized by a higher level of detection of AgNOR proteins [41, 42]. This can be easily explained by the need of the cancer cells to produce more proteins to support the higher proliferation of these cells, and therefore by the need to make more ribosomes to produce these proteins.

Indeed, in many studies, it is described that nucleolin is over-expressed in tumors and cancer cells as detected by RT-QPCR, western blot or immunocytochemistry. For instance, an overexpression of nucleolin was detected in glioblastoma cells [43], hepatocellular carcinoma [44], pancreatic cancer [45], non-small cell lung cancer [46], acute myeloid leukemia [47], breast cancer [48].  However, it is very rare if in these studies the different pools of nucleolin (nucleoplasmic, nucleolar, cytoplasmic and at the cell surface) were discriminated. As the nucleolar pool of nucleolin represents the vast majority of total nucleolin protein, it is very likely that the increased expression of nucleolin results in an increased of this nucleolar pool (which participates to the increased in RNA polymerase I transcription of pre-ribosomal RNA) and also to the other cellular pools. Stating that nucleolin is overexpressed in cancer cells is however an unfortunate simplification found in many research papers and reviews. The real situation is indeed more complicated and finer studies on the level of expression of nucleolin should be done especially using large series of biological samples.

In many studies, the level of expression of nucleolin at the mRNA or protein level is examined in a limited number of biological samples or could even limited to established cell lines representing models for a specific cancer. In these cases, the results should be taken with care, as the expression of nucleolin could greatly fluctuate and be very sensitive to the growth conditions of culture cells.

When large number of samples are used, a wide range of nucleolin fold change is usually observed.  Then, it can become a challenge to determine which expression level represent a “low” versus a “high” expression. The discrimination between “low” and “high” can be done only if enough samples are analyzed and if a good control group is also examined at the same time. Then a “low” nucleolin expression may represent the normal expression found in control samples, or an expression that is lower than in the control group.

In human non-small cell lung cancer (NSCLC), immunohistochemistry was used to measure nucleolin expression in tissues from 225 NSCLC patients [46]. Higher expression of nucleolin was observed in 62,8% of the patients and the authors tried to discriminate the level of nuclear versus cytoplasmic nucleolin expression. If about equal number out of the 225 samples show either a low or high expression of cytoplasmic nucleolin, about 68% of the tumors had a low expression of nuclear nucleolin (and therefore 32% had a high expression of the nuclear pool of nucleolin). In that example, higher nucleolin nuclear level was associated with better survival while high level of cytoplasmic nucleolin was associated with poorer prognosis [46].  The same conclusions was drawn in a study on gastric cancer [49]. Among 124 gastrectomy samples, 68,5 % showed a high nucleolin expression. It was found that a high nucleolar nucleolin expression was associated with a better prognosis while tumors from patients showing a high cytoplasmic detection had the worse prognosis. In most of these studies the elevated total nucleolin expression is associated with a poor prognosis of patients like in gastric cancer, hepatocellular carcinoma, аcute myeloid leukemia, non-small cell lung cancer, pancreatic ductal adenocarcinoma [44, 47, 49–51]. Interestingly, in AML, the higher nucleolin mRNA expression level, compared to normal blasts, was associated with a poor survival only in elderly patients, and was found to be an independent marker [47].

The prognostic value of nucleolin expression was analyzed in acute myeloid leukemia (AML). In this study, the 75^th percentile was used to form the two group of low and high expression [47] using different series of biological samples or TGCA data sets representing 270 samples in total. In this type of cancer, the nucleolin expression was found to cover a very large dispersion. Using this patient stratification, it was found that high nucleolin expression was associated with a poor survival in elderly patients. In a study on the correlation between nucleolin expression and patient outcome with hepatocellular carcinoma, it was found in a series of 130 patients that about 60% of tumors expressed “high” nucleolin expression and 40% a “low” expression [44] with very little explanation on how the cut off was done. The “high” nucleolin expression was then associated with poor prognosis of the patient.

However, it seems that there is not always a strict correlation between the level of nucleolin expression and the aggressiveness of the tumor and the outcome of the prognosis.

In another study in breast cancer, a quartile distribution analysis was first performed and highlighted that two quartiles can be grouped. Therefore, the expression levels could be stratified in three group representing a “low”, “medium” and “high” nucleolin expression [48]. Unexpectedly, using this stratification it was found that “low” and “High” expression levels of nucleolin were both markers of poor survival in triple negative breast cancer (TNBC). Interestingly, transcriptomic analysis of these two groups of samples in the TCGA data base revealed different gene expression profiles suggesting that the tumors in these two groups are different allowing a better stratification of TNBC patients. In agreement with these data, in another independent study, it was found by immunohistochemistry on a panel of 70 TNBC that nucleolin was undetectable in about 20% of these tumor which could correspond to the “low” expression while the expression was “high” in 30% of the tumors [52]. In this study, the authors did not determine if there was a correlation between this patient stratification based on nucleolin expression and the prognostic outcome.

In a study using 69 biological samples from patients with stage II pancreatic ductal adenocarcinoma (PDAC), the authors determined nucleolin expression using immunohistochemistry and scored the nucleolin expression levels using the median nucleolin labeling index as cut off [50]. They found that low level of nucleolin expression was a marker of poor prognosis (19.5 ±3.3 months versus 65.2 ±16.3 months for patients having tumor with a higher nucleolin expression).

Conclusion

In most of the studies, the expression of nucleolin is not homogeneous in the different tumors samples. If overall, the expression of nucleolin seems higher in the majority of the tumors it remains that a substantial number of tumors show a low or intermediate expression of nucleolin. In several cases, the tumors showing a low expression have been also associated with a poor prognosis. In addition, the localization of nucleolin expression within the cells (nuclear versus cytoplasmic) seems to be also important to predict the outcome of the patient. It is therefore important to be able to discriminate the level of nucleolin expression compared to normal tissue (which cutt off is used to make the distinction between high and low expression) and to have enough biological samples to be able to draw any conclusion on the prognostic value of nucleolin expression. As recently shown with breast TNBC series, the stratification of patients according to nucleolin expression level could be an additional criteria to choose  a therapeutic strategy and to develop clinical trials with available molecules that target nucleolin.

Competing interests

The authors declare that he has no competing interests.

Funding information

The research in author team is funded by the Ligue contre le Cancer (Allier and Saone et Loire, France), the Foundation pour la recherche sur le Cancer (ARC) the CNRS, the Ecole Normale Supérieure de Lyon, the Agence Nationale de la Recherche, project ANR Theranuc, ANR-16-CE17-0023. These funding agencies have no roles in the design of the studies, analysis and interpretation of the data, in the writing of the report; and in the decision to submit the paper for publication.

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DOI: 10.31038/CST.2019435

Introduction

Contemporary academic (conventional) medicine, based on current advancements in life sciences and applying evidence based efficacy and safety principles, has evolved from ancient cultures of well-being and healing practices, which originated in prehistoric times, and it co-exists with their ethno-medicine remnants conveniently described as complementary and alternative medicine (CAM) [1, 2]. Global healthcare crisis, which has led to acceptance and even encouragement of CAM practices as an aid to conventional medicine, is a phenomenon of great complexity, comprising processes of various speed and dynamics. In this mini-review we’ll limit discussion to influence of IT and novel scientific knowledge dissemination systems, such as Open Science, to self-medication applied with legally available biologically active substances, but not limited to the OTC drugs.

Discussion

The 21^st century societies differ dramatically from an earlier populations in respect to availability of sound scientific knowledge and specific technical information in every field imaginable, due to widespread IT access (www) to primary source scientific publications and reasonable coverage of scientific achievements through the media. Considerable rise in general education level and computer literacy allowed for massive, profiled individual internet searches, and using their results for informed choice of medicinal and/or CAM treatments. Consequently, a new type of medical patients and pharmacy customers have been created, with considerable potential of modifying future trends on medicinal product markets. Inefficiency of state healthcare systems became notorious not only in the “poor South” regions, but also in the most affluent societies of the industrialized West. In the first case, even relatively small number of WHO selected essential drugs are scarcely available; in the second – thousands of innovative, proprietary active pharmaceutical ingredients (API of the ethical or brand drugs), supplemented by experimental therapies with new molecules in advanced clinical trials, are extremely expensive, with their costs only fractionally covered by insurance. Moreover, efficacy of modern medicines in general is far from satisfactory. This is well exemplified by mortality and morbidity statistics from such principal non-transmittable disease killers as cardiovascular disorders, tumors, and metabolic syndrome, including diabetes [3]. It should be reminded that API substances, estimated as a collection of a few thousand molecules of low molecular weight (biological drugs like vaccines or antibody conjugates form much smaller assembly), consist of a very small fraction of known molecules (ca. 10⁸ chemical entities recorded by CAS database), while natural product collection (e.g.: alkaloids, antibiotics, flavonoids, glycosides, isoprenoids, phenolics, vitamins, etc.) is estimated at 200 thousand, with a fair chance of further growth with advancement on microbial, plants and aquatic organisms metabolome studies. It is therefore not surprising that natural products and especially secondary metabolites (SM), which were developed and genetically encoded as evolutionary traits which provide hosts with some marginal environmental advantages, formed at first a solid base for ethnopharmacology and specifically herbal medicine, and in more recent times afforded countless leads for modern drugs [4,5]. Particularly, among drugs applied in oncology, SM-derived substances account for approximately 60 % of APIs (well-known examples include: taxanes, dimeric indole alkaloids from Catharantus (former Vinca), anthracyclines, camptothecins, podophylotoxins, etc.). These compounds feature selective toxicities, but in general they are biocompatible and follow predictable metabolic pathways, in contrast to many synthetic compounds obtained by combinatorial synthesis for high-throughput screening. Pharmacognosy, a science of SM medical application, which started at the beginning of 19^th century with discovery of alkaloids, was for a long time very close to herbal medicine, which concerned itself mainly with whole plants extracts and concoctions, while individual chemical entities pharmacology development was considerably limited by progress in chemical separation techniques and advancement in analytical chemistry. Currently, legal access to biologically active compounds for nonprofessionals is widely differentiated: from ban on tightly controlled markets of the prescription drugs, through regulations concerning registered over the counter medicines (OTC), to herbal medicines and materials, including high chemical purity isolates of SM, for which various local regulations may apply. The last category is particularly interesting from the point of view of CAM and self-medication, in view of general availability. The herbal medicine markets are already well developed and characterized by dynamic growth. In the US alone, the value of herbal medicines market topped 8 billion $ in 2017, with over 12% growth from year 2016, while the global market value is currently estimated at ca. 100 bln $ [6]. Herbal materials can be segmented into: herbal pharmaceuticals (phytopharmaceuticals; the dominant category), herbal functional foods, herbal dietary supplements and herbal cosmetic products. From the formulation point of view, extracts accounts for the largest markets, and are likely to retain the leading position for a while. In terms of the botanical classification, products derived from the following plants are considered the most significant: Marrubium vulgare, Cinnamomum spp., Vaccinium macrocarpon, Echinacea, Camellia sinensis, Curcuma longa, Actaea racemosa, Aloe vera, Zingiber officinale, Cocos nucifera, Silybum marianum, Gingko biloba, Malpighia punicifolia. Hospital and retail pharmacies are the main distribution channels thus far (over 55% market share) but the internet (e-commerce) sector already shows great potential.

The leader of the herbal products market value classification is, by a large margin – curcumin (turmeric), which is unique in many respects and therefore deserves few comments. The main phenolic constituent of Curcuma longa rhizome (traditional Indian spice and medicine deeply rooted in Ayurveda system and used throughout Asia under various names) was identified as diferuloylmethane at the beginning of 20^th century, and its synthesis was completed thereafter to study a new type of plant pigments capable of dyeing cellulose fibers directly [7]. Turmeric powder, a spice and pigment known as a constituent of food additive popularized in the West as curry, which contain some closely related curcuminoids, is produced in India in multi-ton quantities and distributed by major producers of herbal medicines (encoded E 100 as a food additive and granted the GRAS status by Joint FAO/WHO Expert Committee on Food Additives). High chemical purity curcumin, which became a very popular biochemical and pharmacological molecular probe after initial pharmacological screening, is also freely available. First recognized as an efficient antioxidant, inhibiting COX, LOX and cytochrome P450 promoted metabolism of arachidonic acid, soon attracted attention as an agent which performed extremely well in antiproliferative and antitumor tests [8, 9].

An extensive discussion of curcumin molecular targets, which include transcription factors, growth factors, protein kinases, apoptosis-related proteins, etc., based on the compound structure and chemical reactivity was expertly summarized by concluding that nearly all human cell lines can be inhibited by the compound in vitro; however a big gap exists between its unquestionable pharmacodynamics potential and its feeble pharmacokinetic efficiency, which results from poor solubility, limited metabolic stability and rapid biotransformation in biological media [10]. Such conclusions are in keeping with results of numerous clinical trials, recorded by NIH and reported on PubMed. Meanwhile, search for “curcumin” on Google Scholar (July, 2019) returns ca. 375 000 hits in a small fraction of a second, reflecting a hype of great expectations generated by an avalanche of investigations which suggest medicinal applications of the compound, in particular for prevention and treatment of cancer related ailments. This, obviously is not without influence on a hypothetical well informed customer, interested in a self-care continuum activities, which consists not only of self-managed ailments in minor cases, but includes lifestyle choices (e.g. diet and its supplementation) aimed at long term disease prevention, or intervention in an acute condition. Curcumin seems to provide a good example to illustrate thesis, that an interest in natural products (SM), supplied in form of high purity chemical entities, may soon transform herbal material markets beyond recognition, since all technical means are in place to satisfy such demands. In particular, for many SM with less complicated structures, synthetic chemistry alternatives to isolation exists; next, biotechnology is in line, with growing assembly of gene sequences and clusters which can be expressed in microorganisms already validated for industrial use. In case of a therapeutic indication applications, various sources of the active ingredient may evoke some formal controversies, calling for high-tech arguments based on sophisticated analytical technologies [11] but for “established use” natural products marketing authorizations are usually more freely available. “Adulteration” of natural products with the same substances of synthetic origin are likely to be treated case by case since precedences exist: e. g. some of the curcumin clinical trials were carried out with use of synthetic origin substance.

While the curcumin story stands out among other herbal medicines likely to be applied in CAM procedures, in terms of great abundance of pharmacological results already amassed, it certainly is not the only one plagued with problems of low bioavailability which results in lack of in vivo efficacy. To this point, some facts from the rich history of ascorbic acid (Vit. C) medical applications should be reminded. Recognition of antiscorbutic action of Vit. C isolated from citrus fruits, was followed by Albert Szent-Győrgyi observation that it worked much better in the presence of green pepper flavonoids, temporarily advanced to a vitamin status [12]. The value of ascorbic acid for fighting cancers is disputable and necessity for exorbitantly large doses delivered by intravenous injections is discouraging [13], but the idea of “enhancers”, which are not active per se but significantly improve bioavailability of other API substances is alive and well. For curcumin, alkaloid piperine is indicated as the effective enhancer, and co-formulations of these compounds are believed to secure progress towards improved BA. Flavonoids, which are a large family of SM, closely related by phenylpropanoid biogenetic pathways, have not recovered vitamin P status, but many compounds from that category feature extremely interesting biological activities with prospective medicinal applications: in practically all structural sub-categories – chalcones, flavanones, flavonols, flavones, isoflavones, catechins and anthocyanes there are numerous examples of such health promoting activities, which are attractive from the point of view of CAM practices and metabolic syndrome prevention [14].

Genistein, the isoflavone with the most publicized record of research in oncological pharmacology [15, 16] should in principle be available in multi-ton quantities, since one of the main agricultural crops in global scale – the soybeans (over 300 mln tons harvested annually) contain on average ca. 0.1% of the compound, but thus far has not made it to natural origin chemicals distribution channels at affordable prices. Despite of its poor oral bioavailability, interest in genistein chemopreventive potential is high, GRAS status secures entry into modified food segment, and the compound is relatively easily available from chemical synthesis. Like in the case of “Indian gold” – curcumin, there is no shortage of sound, scientific information on flavonoids pharmacological activity, propagated through Open Access channels. In summary, a number of individual chemical entities of natural origin ready to join traditional pool of herbal medicines is large, which offers an outstanding opportunity for healthcare related innovations, focused on opening markets for new type of customers seeking specified, high quality materials from SM category, for self-managed healthcare.

Acknowledgment

The author is involved in the ORBIS project that received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778051 and the Ministry of Science and Higher Education of Poland fund for supporting internationally co-financed projects in 2018–2022 (agreement No 3898/H2020/2018/2). The views expressed in this article are those of the author and the Research Executive Agency is not responsible for any use that may be made of the information it contains.

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