The origins of urothelial carcinoma

Precision Medicine in Bladder Cancer: Present Challenges and Future Directions

Bladder cancer (BC) is characterized by significant histopathologic and molecular heterogeneity. The discovery of molecular pathways and knowledge of cellular mechanisms have grown exponentially and may allow for better disease classification, prognostication, and development of novel and more efficacious noninvasive detection and surveillance strategies, as well as selection of therapeutic targets, which can be used in BC, particularly in a neoadjuvant or adjuvant setting. This article outlines recent advances in the molecular pathology of BC with a better understanding and deeper focus on the development and deployment of promising biomarkers and therapeutic avenues that may soon make a transition into the domain of precision medicine and clinical management for patients with BC.

Frequent Telomerase Reverse Transcriptase (TERT) Promoter and Fibroblast Growth Factor Receptor 3 (FGFR3) Mutations Support the Precursor Nature of Papillary Urothelial Hyperplasia of the Urinary Bladder

The precursor nature of papillary urothelial hyperplasia of the urinary bladder is uncertain. In this study, we investigated TERT promoter and FGFR3 mutations in 82 patients with papillary urothelial hyperplasia lesions. Thirty eight patients presented with papillary urothelial hyperplasia and concurrent non-invasive papillary urothelial carcinoma and 44 patients presented with de novo papillary urothelial hyperplasia. The prevalence of TERT promoter and FGFR3 mutation are compared between de novo papillary urothelial hyperplasia and those with concurrent papillary urothelial carcinoma. Mutational concordance between papillary urothelial hyperplasia and concurrent carcinoma were also compared. The TERT promoter mutations were detected in 44% (36/82) of papillary urothelial hyperplasia including 23 (23/38, 61%) papillary urothelial hyperplasia with urothelial carcinoma, and 13 (13/44, 29%) de novo papillary urothelial hyperplasia. The overall concordance of TERT promoter mutation status between papillary urothelial hyperplasia and concurrent urothelial carcinoma was 76%. Overall FGFR3 mutation rate of papillary urothelial hyperplasia was 23% (19/82). FGFR3 mutations were detected in 11 patients with papillary urothelial hyperplasia and concurrent urothelial carcinoma (11/38, 29%), and 8 patients with de novo papillary urothelial hyperplasia (8/44, 18%). Identical FGFR3 mutation status was detected in both papillary urothelial hyperplasia and urothelial carcinoma component in all 11 patients with FGFR3 mutations. Our findings provide strong evidence of genetic association between papillary urothelial hyperplasia and urothelial carcinoma. High frequency of TERT promoter and FGFR3 mutations suggests the precursor role of papillary urothelial hyperplasia in urothelial carcinogenesis.

Biological and clinical perspectives of TERT promoter mutation detection on bladder cancer diagnosis and management

The telomerase reverse transcriptase (TERT) promoter mutations are associated with increased TERT mRNA and TERT protein levels, telomerase activity, and shorter but stable telomere length. TERT promoter mutation is the most common mutation that occurs in approximately 60-80% of patients with bladder cancer. The TERT promoter mutations occur in a wide spectrum of urothelial lesions, including benign urothelial proliferation and tumor-like conditions, benign urothelial tumors, premalignant and putative precursor lesions, urothelial carcinoma and its variants, and nonurothelial malignancies. The prevalence and incidence of TERT promoter mutations in a total of 7259 cases from the urinary tract were systematically reviewed. Different platforms of TERT promoter mutation detection were presented. In this review, we also discussed the significance and clinical implications of TERT promoter mutation detection in urothelial tumorigenesis, surveillance and early detection, diagnosis, differential diagnosis, prognosis, prediction of treatment responses, and clinical outcome. Identification of TERT promoter mutations from urine or plasma cell-free DNA (liquid biopsy) will facilitate bladder cancer screening program and optimal clinical management. A better understanding of TERT promoter mutation and its pathway would open new therapeutic avenues for patients with bladder cancer.

E-liquid exposure induces bladder cancer cells to release extracellular vesicles that promote non-malignant urothelial cell transformation

The vaping of electronic cigarettes (E-cigarettes) has recently emerged as a popular alternative to traditional cigarette smoking, but its association with bladder cancer (BC) risk remains to be established. BC patients exhibit high rates of recurrent disease, possibly as a consequence of the field cancerization effect. We have shown that BC-derived extracellular vesicles (BCEVs) can permanently alter recipient urothelial cells in predisposed fields such that they become fully transformed malignant cells. To model the role that BCEVs may play in this potentially oncogenic setting, we treated TCCSUP BC cells with cigarette smoke extract, unflavored E-liquid, or menthol flavored E-liquid. Those treated BCEVs were then tested for their tumorigenic potential. We found that these smoking- and E-cigarette-related BCEVs were able to promote oxidative stress, inflammatory signaling, and DNA damage in recipient SV-HUC urothelial cells. Strikingly, menthol E-liquid-induced BCEVs significantly increased rates of malignant urothelial cell transformation. While further in vivo validation of the simultaneous effects of E-liquid and E-liquid-induced BCEVs on field cancerization is needed, these data highlight the possibility that E-cigarettes may compound user risk in a manner that can contribute to higher rates of BC incidence or recurrence.

Use of Artificial Intelligence for the Interpretable Prediction of the Pathologic Diagnosis and Molecular Abnormalities of Flat Urothelial Lesions

Flat urothelial lesions are important because of their potential for carcinogenesis and development into invasive urothelial carcinomas. However, it is difficult for pathologists to detect early flat urothelial changes and accurately diagnose flat urothelial lesions. To predict the pathologic diagnosis and molecular abnormalities of flat urothelial lesions from pathologic images, artificial intelligence with an interpretable method was used. Next-generation sequencing on 110 hematoxylin and eosin-stained slides of normal urothelium and flat urothelial lesions, including atypical urothelium, dysplasia, and carcinoma in situ, detected 17 types of molecular abnormalities. To generate an interpretable prediction, a new method for segmenting urothelium and a new pathologic criteria-based artificial intelligence (PCB-AI) model was developed. κ Statistics and accuracy measurements were used to evaluate the ability of the model to predict the pathologic diagnosis. The likelihood ratio test was performed to evaluate the logistic regression models for predicting molecular abnormalities. The diagnostic prediction of the PCB-AI model was almost in perfect agreement with the pathologists' diagnoses (weighted κ = 0.98). PCB-AI significantly predicted some molecular abnormalities in an interpretable manner, including abnormalities of TP53 (P = 0.02), RB1 (P = 0.04), and ERCC2 (P = 0.04). Thus, this study developed a new method of obtaining accurate urothelial segmentation, interpretable prediction of pathologic diagnosis, and interpretable prediction of molecular abnormalities.

Molecular Classification of Bladder Urothelial Carcinoma Using NanoString-Based Gene Expression Analysis

Simple Summary

Our study aimed to apply a quantitative method based on mRNA counting as nCounter (NanoString Technologies, Inc). This method can obtain precise and accurate measures of RNA expression compared to RT-PCR, and which might represent an alternative to the NGS-genomic/transcriptomic profiling frequently used to generate molecular data in bladder cancer and provide clinically meaningful datasets for the molecular classification of bladder cancer. The current study generated a four-gene classifier, incorporating GATA3 and KRT20 (typically related to luminal molecular subtype) and KRT5 and KRT14 (typically related to basal molecular subtype). This methodology allowed us to explore differences in clinicopathologic parameters and potential sensitivities to ICI immunotherapy in a cohort series of 91 urothelial carcinomas of the bladder.

Abstract

Molecular classification of bladder carcinoma is a relevant topic in modern bladder cancer oncology due to its potential to improve oncological outcomes. The available molecular classifications are generally based on transcriptomic profiles, generating highly diverse categories with limited correlation. Implementation of molecular classification in practice is typically limited due to the high complexity of the required technology, the elevated costs, and the limited availability of this technology worldwide. We have conducted a gene expression analysis using a four-gene panel related to luminal and basal subtypes in a series of 91 bladder cancer cases. NanoString-based gene expression analysis using typically luminal (GATA3+/KRT20+) and basal markers (KRT14+/KRT5+/GATA3low/-/KRT20low/-) classified urothelial bladder carcinoma samples as luminal, basal, and a third category (KRT14-/KRT5-/GATA3-/KRT20-), null/double negative (non-luminal/non-basal). These three categories were meaningful in terms of overall cancer-specific survival (p < 0.0001) or when classified as conventional urothelial carcinoma and variant histology urothelial carcinoma (p < 0.0001), NMIBC vs. MIBC (p < 0.001), or by AJCC stage category Ta (p = 0.0012) and T1 (p < 0.0001) but did not reach significance in T2-T4 (p = 0.563). PD-L1 expression (low vs. high) was also different according to molecular subtype, with high PD-L1 expression mostly seen in basal and null subtypes and carcinomas with variant histology (p = 0.002). Additionally, the luminal subtype was enriched in NMIBC with favorable cancer-specific survival (p < 0.0001). In contrast, basal and null subtypes resulted in aggressive MIBC tumors with shorter cancer-specific survival (p < 0.0001), some of which presented variant histology. In conclusion, a comprehensive evaluation of a gene classifier related to molecular taxonomy using NanoString technology is feasible. Therefore, it might represent an accessible and affordable tool in this rapidly expanding area of precision genomics.

Fibroblast growth factor receptor (FGFR) gene: pathogenesis and treatment implications in urothelial carcinoma of the bladder

Dysregulation of fibroblast growth factor receptors (FGFRs) has been implicated in several human malignancies, including urothelial carcinoma. In urothelial carcinoma, the oncogenic role of mutated FGFR is mediated by the RAS-mitogen-activated protein kinase pathway, resembling the effects observed with activated HRAS Activating somatic mutations of FGFR3 are clustered in three hotspots in exons 7, 10 and 15, and are almost always missense mutations leading to amino acid substitution in the external, transmembrane or intracellular regions of the receptor. A fusion of FGFR3 to transforming acid coiled-coil containing protein 3, FGFR3 amplification and alternative splicing leading to aberrant FGFR3 activation are less common molecular alterations. In April 2020, the Food and Drug Administration (FDA) approved the first targeted FGFR therapy, erdafitinib, in patients with locally advanced or metastatic bladder cancer who have progressed on platinum-based chemotherapy. Herein, we reviewed the normal structure and function of FGFR We also explored its role in the development of urothelial carcinoma and major developments in the FGFR-targeted therapy.

Tumour-like lesions of the urinary bladder

There are a number of benign epithelial proliferations in the bladder that may be difficult to distinguish from carcinomas, including urothelial carcinoma and its variants, squamous cell carcinoma and adenocarcinoma. If misdiagnosed, there is the potential for over treatment, with its attendant risk of complications, as well as errors relating to prognostic assessment. In the case of the misdiagnosis of high grade proliferative lesions that mimic invasive carcinoma, unnecessary radical surgery, chemotherapy and radiotherapy may result. Similarly, the misdiagnosis of lesions that have the appearance of low grade carcinoma can prompt a lifetime of radiological investigation and cystoscopies. In this review, we discuss a variety of entities that may be diagnostically challenging and emphasise the importance of identifying key morphological features that have diagnostic utility. We also highlight the importance of relevant clinical information and the clinical settings in which these lesions may occur. In this review we have divided the lesions on the basis of morphology in order to facilitate discussion relating to the differential diagnosis. The architectural patterns we discuss include papillary lesions (polypoid/papillary cystitis and papillary urothelial hyperplasia), pseudocarcinomatous proliferations (pseudocarcinomatous urothelial hyperplasia, florid proliferation of von Brunn nests and fibroepithelial polyps), glandular lesions (intestinal metaplasia and müllerianosis) and lesions with several different patterns (prostatic type urethral polyps and nephrogenic adenoma or metaplasia).

Urothelial Carcinoma In Situ (CIS): New Insights

Urothelial carcinoma in situ (CIS) is a high-grade noninvasive malignancy with a high tendency of progression. Although it is typically grouped with other nonmuscle invasive bladder cancers, its higher grade and aggressiveness make it a unique clinical entity. Urothelial CIS is histologically characterized by replacement of the urothelium by cells which fulfill the morphologic criteria of malignancy including nuclear pleomorphism, hyperchromasia, prominent nucleoli, and increased numbers of normal and abnormal mitoses. Urothelial CIS may be categorized as primary when it is not associated with any past or present urothelial carcinoma. It is termed as secondary when there is concomitant or previous urothelial carcinoma in the patient. In recent years detailed molecular studies have provided valuable data for intrinsic molecular subclassification of urothelial carcinoma into 2 broad categories namely luminal and basal types with significant implications for prognosis and therapy. Similar studies on urothelial CIS are limited but have provided crucial insight into the molecular basis of CIS. These studies have revealed that urothelial CIS may also be divided into luminal and basal subtypes, but luminal subtype is much more common. It has also been shown that in many cases, luminal type of urothelial CIS may undergo a class switch to basal type during progression to an invasive carcinoma. Additional studies may be required to confirm and further elaborate these findings.

Precancer in ulcerative colitis: the role of the field effect and its clinical implications

Cumulative evidence indicates that a significant proportion of cancer evolution may occur before the development of histological abnormalities. While recent improvements in DNA sequencing technology have begun to reveal the presence of these early preneoplastic clones, the concept of 'premalignant field' was already introduced by Slaughter more than half a century ago. Also referred to as 'field effect', 'field defect' or 'field cancerization', these terms describe the phenomenon by which molecular alterations develop in normal-appearing tissue and expand to form premalignant patches with the potential to progress to dysplasia and cancer. Field effects have been well-characterized in ulcerative colitis, an inflammatory bowel disease that increases the risk of colorectal cancer. The study of the molecular alterations that define these fields is informative of mechanisms of tumor initiation and progression and has provided potential targets for early cancer detection. Herein, we summarize the current knowledge about the molecular alterations that comprise the field effect in ulcerative colitis and the clinical utility of these fields for cancer screening and prevention.

Diagnostic difficulties in cases of papillary urothelial neoplasm of low malignant potential, urothelial proliferation of uncertain malignant potential, urothelial dysplasia and urothelial papilloma: A review of current literature

Tumours of the urinary tract are the fifth most frequent type of cancer. The most common types are urothelial tumours, among which, non-invasive urothelial neoplasms represent 45% of all cases. The 2016 WHO classification of urinary tract tumours introduced new classifications of non-invasive lesions. Besides urothelial papilloma (UP) and papillary urothelial neoplasm of low malignant potential (PUNLMP), as described in the former classification, the new classification also includes new entities such as urothelial proliferation of uncertain malignant potential (UPUMP) and urothelial dysplasia (UD). Of the aforementioned, UPUMP is the lesion that most commonly progresses, but solely to non-invasive carcinomas. UD is associated with a high risk of progression to invasive carcinoma. Understanding the biological character, and establishing the correct differential diagnosis in cases of non-invasive, non-cancerous lesions of the urinary bladder, will be of importance in establishing outcome predictions for future patients. A systematic review of the current literature allows us to systematize genetic, morphologic and prognostic factors of such lesions. Moreover, the collected data provide the basis for a proposed diagnostic algorithm which facilitates quick and effective differential diagnoses in cases of non-invasive non-cancerous urinary bladder lesions.

Promoter hypermethylation of LGALS4 correlates with poor prognosis in patients with urothelial carcinoma

Galectine-4 (gal-4), encoded by the LGALS4 gene, was recently shown to exhibit a tumor suppressive effect in colorectal carcinoma and pancreatic adenocarcinoma, although how the expression of this gene is regulated remains unknown. No reports describe the significance of gal-4 in the malignant potential of urothelial tumors. Thus, we analyzed LGALS4 methylation and gene expression and their clinical relevance and biological function in urothelial carcinoma (UC). LGALS4 methylation was initially identified as a progression biomarker for UC patients through genome-wide DNA methylation profiling of 16 tumor samples. Bisulfite sequencing PCR and immunohistochemistry were performed to validate the promoter methylation and expression of LGALS4. We used quantitative methylation-specific PCR to determine the methylation levels of LGALS4 normalized to ACTB in the tumor samples of 79 UC patients and compared the levels between patients with different clinicopathological characteristics. The association with survival probability was analyzed with the Kaplan-Meier method and Cox regression analysis. The ectopic expression of gal-4 in cancer cell lines was used to address its biological function in UC in vitro. The promoter hypermethylation of LGALS4 (>2.51, log₁₀ scale) revealed a positive correlation with high levels of both histological grade and tumor T category and with lymph node metastasis (all P≤0.001). In addition, LGALS4 hypermethylation was an independent predictor of inferior survival in UC patients (P<0.05). The ectopic expression studies demonstrated that gal-4 suppressed urothelial cancer cell growth, migration, and invasion. Thus, LGALS4 may function as a tumor suppressor gene in UC progression. Our findings provide evidence that methylation-mediated LGALS4 gene repression may be involved in urothelial tumor progression.

Urothelial generation and regeneration in development, injury, and cancer

Homeostatic maintenance and repair of the urothelium upon injury are required for a functional bladder in both healthy and disease conditions. Understanding the cellular and molecular mechanisms underlying the urothelial regenerative response is key to designing strategies for tissue repair and ultimately treatments for urologic diseases including urinary tract infections, voiding dysfunction, painful bladder syndrome, and bladder cancer. In this article, we review studies on urothelial ontogeny during development and regeneration following various injury modalities. Signaling pathways involved in urothelial regeneration and in urothelial carcinogenesis are also discussed. Developmental Dynamics 246:336-343, 2017. © 2016 Wiley Periodicals, Inc.

Expression of circadian clock genes and proteins in urothelial cancer is related to cancer-associated genes

Background

The purpose of this study was to evaluate invasive and metastatic potential of urothelial cancer by investigating differential expression of various clock genes/proteins participating in the 24 h circadian rhythms and to compare these gene expressions with transcription of other cancer-associated genes.

Methods

Twenty seven paired samples of tumour and benign tissue collected from patients who underwent cystectomy were analysed and compared to 15 samples of normal bladder tissue taken from patients who underwent cystoscopy for benign prostate hyperplasia (unrelated donors). Immunohistochemical analyses were made for clock and clock-related proteins. In addition, the gene-expression levels of 22 genes (clock genes, casein kinases, oncogenes, tumour suppressor genes and cytokeratins) were analysed by real-time quantitative PCR (qPCR).

Results

Considerable up- or down-regulation and altered cellular distribution of different clock proteins, a reduction of casein kinase1A1 (CSNK1A1) and increase of casein kinase alpha 1 E (CSNK1E) were found. The pattern was significantly correlated with simultaneous up-regulation of stimulatory tumour markers, and a down-regulation of several suppressor genes. The pattern was mainly seen in aneuploid high-grade cancers. Considerable alterations were also found in the neighbouring bladder mucosa.

Conclusions

The close correlation between altered expression of various clock genes and common tumour markers in urothelial cancer indicates that disturbed function in the cellular clock work may be an important additional mechanism contributing to cancer progression and malignant behaviour.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2580-y) contains supplementary material, which is available to authorized users.

Understanding the molecular pathogenesis and prognostics of bladder cancer: an overview

The knowledge of cellular mechanisms in malignances of the bladder has grown exponentially. Molecular technologies have led to the discovery of the molecular pathways distinguishing low-and high-grade urothelial neoplasms. This trend portends the future in which the classification and diagnosis of the bladder tumors through morphologic analysis will be supported by molecular information correlating with prognosis and targeted therapy. This article outlines tumor molecular pathology of bladder cancer with an emphasis on several promising candidate biomarkers that may soon make their transition to the realm of clinical management of bladder cancer.

Emerging Bladder Cancer Biomarkers and Targets of Therapy

Bladder cancer is a heterogeneous disease characterized by complex networks of molecular alterations and gene expression. This review summarizes some of the recent genomic studies that have further advanced the understanding of the pathways driving bladder cancer, highlighting several important biomarkers and potential targeted therapeutic strategies that are now in clinical trials. In addition, noninvasive techniques to evaluate biomarkers in patients' urine and serum for early detection and surveillance are discussed.

Somatic mosaicism: on the road to cancer

Diversity is the basis of fitness selection. Although the genome of an individual is considered to be largely stable, there is theoretical and experimental evidence--both in model organisms and in humans--that genetic mosaicism is the rule rather than the exception. The continuous generation of cell variants, their interactions and selective pressures lead to life-long tissue dynamics. Individuals may thus enjoy 'clonal health', defined as a clonal composition that supports healthy morphology and physiology, or suffer from clonal configurations that promote disease, such as cancer. The contribution of mosaicism to these processes starts during embryonic development. In this Opinion article, we argue that the road to cancer might begin during these early stages.

Etiologic field effect: reappraisal of the field effect concept in cancer predisposition and progression

The term 'field effect' (also known as field defect, field cancerization, or field carcinogenesis) has been used to describe a field of cellular and molecular alteration, which predisposes to the development of neoplasms within that territory. We explore an expanded, integrative concept, 'etiologic field effect', which asserts that various etiologic factors (the exposome including dietary, lifestyle, environmental, microbial, hormonal, and genetic factors) and their interactions (the interactome) contribute to a tissue microenvironmental milieu that constitutes a 'field of susceptibility' to neoplasia initiation, evolution, and progression. Importantly, etiological fields predate the acquisition of molecular aberrations commonly considered to indicate presence of filed effect. Inspired by molecular pathological epidemiology (MPE) research, which examines the influence of etiologic factors on cellular and molecular alterations during disease course, an etiologically focused approach to field effect can: (1) broaden the horizons of our inquiry into cancer susceptibility and progression at molecular, cellular, and environmental levels, during all stages of tumor evolution; (2) embrace host-environment-tumor interactions (including gene-environment interactions) occurring in the tumor microenvironment; and, (3) help explain intriguing observations, such as shared molecular features between bilateral primary breast carcinomas, and between synchronous colorectal cancers, where similar molecular changes are absent from intervening normal colon. MPE research has identified a number of endogenous and environmental exposures which can influence not only molecular signatures in the genome, epigenome, transcriptome, proteome, metabolome and interactome, but also host immunity and tumor behavior. We anticipate that future technological advances will allow the development of in vivo biosensors capable of detecting and quantifying 'etiologic field effect' as abnormal network pathology patterns of cellular and microenvironmental responses to endogenous and exogenous exposures. Through an 'etiologic field effect' paradigm, and holistic systems pathology (systems biology) approaches to cancer biology, we can improve personalized prevention and treatment strategies for precision medicine.

Validation and clinicopathologic associations of a urine-based bladder cancer biomarker signature

Background

To validate the expression of a urine-based bladder cancer associated diagnostic signature comprised of 10 targets; ANG, CA9, MMP9, MMP10, SERPINA1, APOE, SDC1, VEGFA, SERPINE1 and IL8 in bladder tumor tissues.

Methods

Immunohistochemical analyses were performed on tumor specimens from 213 bladder cancer patients (transitional cell carcinoma only) and 74 controls. Staining patterns were digitally captured and quantitated (Aperio, Vista, CA), and expression was correlated with tumor stage, tumor grade and outcome measures.

Results

We revealed a positive association of 9 of the 10 proteins (excluding VEGF) in bladder cancer. Relative to control cases, a reduction in SDC1 and overexpression of MMP9, MMP10, SERPINE1, IL8, APOE, SERPINA1, ANG were associated with high stage bladder cancer. Reduced VEGF and increased SERPINA1 were associated with high-grade bladder cancer. Disease-specific survival was significantly reduced in tumors with high expression of SERPINE1 and/or IL8.

Conclusions

These findings confirm that the proteins in a urine-based diagnostic signature are aberrantly expressed in bladder tumor tissues, and support the potential additional utility of selected biomarkers for the clinicopathological evaluation of excised tissue or biopsy material.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_200

Biomarkers in bladder cancer: translational and clinical implications

Bladder cancer is associated with high recurrence and mortality rates. These tumors show vast heterogeneity reflected by diverse morphologic manifestations and various molecular alterations associated with these disease phenotypes. Biomarkers that prospectively evaluate disease aggressiveness, progression risk, probability of recurrence and overall prognosis would improve patient care. Integration of molecular markers with conventional pathologic staging of bladder cancers may refine clinical decision making for the selection of adjuvant and salvage therapy. In the past decade, numerous bladder cancer biomarkers have been identified, including various tumor suppressor genes, oncogenes, growth factors, growth factor receptors, hormone receptors, proliferation and apoptosis markers, cell adhesion molecules, stromal factors, and oncoproteins. Recognition of two distinct pathways for urothelial carcinogenesis represents a major advance in the understanding and management of this disease. Nomograms for combining results from multiple biomarkers have been proposed to increase the accuracy of clinical predictions. The scope of this review is to summarize the major biomarker findings that may have translational and clinical implications.

Overexpression of p16(INK4a) in urothelial carcinoma in situ is a marker for MAPK-mediated epithelial-mesenchymal transition but is not related to human papillomavirus infection

BACKGROUND

The role of human papillomavirus (HPV) in bladder carcinogenesis remains controversial. Overexpression of p16(INK4a), a surrogate marker for infection with oncogenic HPV in other tumours, has been described for urothelial carcinoma in situ (UCIS). Our goal was therefore to evaluate whether overexpression of p16(INK4a) is associated with HPV infection and to identify mechanisms of p16(INK4a) upregulation in UCIS.

MATERIALS AND METHODS

In 60 tissue specimens from a total of 45 patients (UCIS and controls), we performed p16(INK4a) immunohistochemistry followed by detection and subclassification of HPV DNA. In a subset of samples, we tested for gene amplification of p16(INK4a) applying fluorescence in situ hybridization (FISH). RAS/MAPK signalling and epithelial-mesenchymal transition (EMT) was assessed using immunohistochemistry. Finally, we transfected urothelial carcinoma cells with KRAS and examined the expression of p16(INK4a) as well as markers of EMT.

RESULTS

We found overexpression of p16(INK4a) in 92.6% of UCIS and in all cervical intraepithelial neoplasia (CIN) controls. In contrast, we detected high-risk HPV DNA in 80% of CIN, but none in UCIS. There was no gene amplification of p16(INK4a). High levels of phosphorylated kinases and urokinase plasminogen activator (uPA) and loss of membraneous E-cadherin were detected in UCIS. KRAS transfection of urothelial carcinoma cells led to upregulation of p16(INK4a) and uPA accompanied by loss of E-cadherin that could be inhibited by application of the kinase-inhibitor Sorafenib.

CONCLUSIONS

Our results show that overexpression of p16(INK4a) in UCIS is neither associated with HPV infection nor p16(INK4a) gene amplification but is a consequence of enhanced RAS/MAPK signalling that promotes EMT, possibly due to Sorafenib-sensitive paracrine secretion of the EMT activator uPA. These findings might open a novel therapeutic option for localized but aggressive urothelial cancer.

Clinical applications of recent molecular advances in urologic malignancies: no longer chasing a "mirage"?

As our understanding of the molecular events leading to the development and progression of genitourologic malignancies, new markers of detection, prognostication, and therapy prediction can be exploited in the management of these prevalent tumors. The current review discusses the recent advances in prostate, bladder, renal, and testicular neoplasms that are pertinent to the anatomic pathologist.

Molecular Pathology of Bladder Cancer

This article focuses on several promising candidate biomarkers that may soon make their transition to the realm of clinical management of bladder cancer. Presented are superficial and muscle-invasive urothelial carcinoma of the bladder and the genetic tests currently available in testing for diagnosis and prognosis of these diseases.

Intracholecystic papillary-tubular neoplasms (ICPN) of the gallbladder (neoplastic polyps, adenomas, and papillary neoplasms that are ≥1.0 cm): clinicopathologic and immunohistochemical analysis of 123 cases

The literature on the clinicopathologic characteristics of tumoral intraepithelial neoplasms (neoplastic polyps) of the gallbladder (GB) is fairly limited, due in part to the variability in definition and terminology. Most reported adenomas (pyloric gland type and others) were microscopic and thus regarded as clinically inconsequential, whereas papillary in situ carcinomas have been largely considered a type of invasive adenocarcinoma under the heading of "papillary adenocarcinomas." In this study, 123 GB cases that have a well-defined exophytic preinvasive neoplasm measuring ≥1 cm were analyzed. The patients were predominantly female (F/M=2:1) with a mean age of 61 y and a median tumor size of 2.2 cm. Half of the patients presented with pain, and in the other half the neoplasm was detected incidentally. Other neoplasms, most being gastrointestinal tract malignancies, were present in 22% of cases. Gallstones were identified in only 20% of cases. Radiologically, almost half were diagnosed as "cancer," roughly half with polypoid tumor, and in 10% the lesion was missed. Pathologic findings: (1) The predominant configuration was papillary in 43%, tubulopapillary in 31%, tubular in 26%. (2) Each case was assigned a final lineage type on the basis of the predominant pattern (>75% of the lesion) on morphology, and supported with specific immunohistochemical cell lineage markers. The predominant cell lineage could be identified as biliary in 50% (66% of which were MUC1), gastric foveolar in 16% (all were MUC5AC), gastric pyloric in 20% (92% MUC6), intestinal in 8% (100% CK20; 75% CDX2; 50%, MUC2), and oncocytic in 6% (17% HepPar and 17% MUC6); however, 90% of cases had some amount of secondary or unclassifiable pattern and hybrid immunophenotypes. (3) Of the cases that would have qualified as "pyloric gland adenoma," 21/24 (88%) had at least focal high-grade dysplasia and 18% had associated invasive carcinoma. Conversely, 8 of 47 "papillary adenocarcinoma"-type cases displayed some foci of low-grade dysplasia, and 15/47 (32%) had no identifiable invasion. (4) Overall, 55% of the cases had an associated invasive carcinoma (pancreatobiliary type, 58; others, 10). Factors associated significantly with invasion were the extent of high-grade dysplasia, cell type (biliary or foveolar), and papilla formation. Among systematically analyzed invasive carcinomas, tumoral intraepithelial neoplasia was detected in 6.4% (39/606). (5) The 3-year actuarial survival was 90% for cases without invasion and 60% for those associated with invasion. In contrast, those associated with invasion had a far better clinical outcome compared with pancreatobiliary-type GB carcinomas (3-yr survival, 27%), and this survival advantage persisted even with stage-matched comparison. Death occurred in long-term follow-up even in a few noninvasive cases (4/55; median 73.5 mo) emphasizing the importance of long-term follow-up. In conclusion, tumoral preinvasive neoplasms (≥1 cm) in the GB are analogous to their pancreatic and biliary counterparts (biliary intraductal papillary neoplasms, pancreatic intraductal papillary mucinous neoplasms, and intraductal tubulopapillary neoplasms). They show variable cellular lineages, a spectrum of dysplasia, and a mixture of papillary or tubular growth patterns, often with significant overlap, warranting their classification under 1 unified parallel category, intracholecystic papillary-tubular neoplasm. Intracholecystic papillary-tubular neoplasms are relatively indolent neoplasia with significantly better prognosis compared with pancreatobiliary-type GB carcinomas. In contrast, even seemingly innocuous examples such as those referred to as "pyloric gland adenomas" can progress to carcinoma and be associated with invasion and fatal outcome.

Mismatch repair hMSH2, hMLH1, hMSH6 and hPMS2 mRNA expression profiles in precancerous and cancerous urothelium

Changes in the expression of the mismatch repair (MMR) genes hMSH2, hMLH1, hMSH6 and hPMS2 reflect dysfunction of the DNA repair system that may allow the malignant transformation of tissue cells. The aim of the present study was to address the mRNA expression profiles of the mismatch DNA repair system in cancerous and precancerous urothelium. This is the first study to quantify MMR mRNA expression by applying quantitative real-time PCR (qPCR) and translate the results to mRNA phenotypic profiles (r, reduced; R, regular or elevated) in bladder tumors [24 urothelial cell carcinomas (UCCs) and 1 papillary urothelial neoplasm of low malignant potential (PUNLMP)] paired with their adjacent normal tissues (ANTs). Genetic instability analysis was applied at polymorphic sites distal or close to the hMSH2 and hMLH1 locus. Presenting our data, reduced hMSH2, hMSH6 and hPMS2 mRNA expression profiles were observed in cancerous and precancerous urothelia. Significantly, the ANTs of UCCs revealed the highest percentages of reduced hMSH2 (r(2)), hMSH6 (r(6)) and hPMS2 (p(2)) mRNA phenotypes relative to their tumors (P<0.03). In particular, combined r(2)r(6) (P<0.02) presented a greater difference between ANTs of low-grade UCCs vs. their tumors compared with ANTs of high-grade UCCs (P= 0.000). Reduced hMLH1 (r(1)) phenotype was not expressed in precancerous or cancerous urothelia. The hMSH6 mRNA was the most changed in UCCs (47.8%), while hMSH2, hMLH1 and hPMS2 showed overexpression (47.8, 35 and 30%, respectively) that was associated with gender and histological tumor grading or staging. Genetic instability was rare in polymorphic regions distal to hMLH1. Our data reveal a previously unrecognized hMSH2 and hMSH6 mRNA combined phenotype (r(2)r(6)) correlated with a precancerous urothelium and show that hMLH1 is transcriptionally activated in precancerous or cancerous urothelium. In the present study, it is demonstrated that reduction of hMSH6 mRNA is a frequent event in bladder tumorigenesis and reflects a common mechanism of suppression with hMSH2, while alterations of hMSH2 or hMLH1 mRNA expression in UCCs does not correlate with the allelic imbalance of polymorphic regions harboring the genes.

Oncolytic viruses in the treatment of bladder cancer

Bladder carcinoma is the second most common malignancy of the urinary tract. Up to 85% of patients with bladder cancer are diagnosed with a tumor that is limited to the bladder mucosa (Ta, T1, and CIS). These stages are commonly termed as non-muscle-invasive bladder cancer (NMIBC). Although the treatment of NMIBC has greatly improved in recent years, there is a need for additional therapies when patients fail bacillus Calmette-Guérin (BCG) and chemotherapeutic agents. We propose that bladder cancer may be an ideal target for oncolytic viruses engineered to selectively replicate in and lyse tumor cells leaving normal cells unharmed. In support of this hypothesis, here we review current treatment strategies for bladder cancer and their shortcomings, as well as recent advancements in oncolytic viral therapy demonstrating encouraging safety profiles and antitumor activity.

Epithelial plasticity, cancer stem cells, and the tumor-supportive stroma in bladder carcinoma

High recurrence rates and poor survival rates of metastatic bladder cancer emphasize the need for a drug that can prevent and/or treat bladder cancer progression and metastasis formation. Accumulating evidence suggests that cancer stem/progenitor cells are involved in tumor relapse and therapy resistance in urothelial carcinoma. These cells seem less affected by the antiproliferative therapies, as they are largely quiescent, have an increased DNA damage response, reside in difficult-to-reach, protective cancer stem cell niches and express ABC transporters that can efflux drugs from the cells. Recent studies have shown that epithelial-to-mesenchymal transition (EMT), a process in which sessile, epithelial cells switch to a motile, mesenchymal phenotype may render cancer cells with cancer stem cells properties and/or stimulate the expansion of this malignant cellular subpopulation. As cancer cells undergo EMT, invasiveness, drug resistance, angiogenesis, and metastatic ability seem to increase in parallel, thus giving rise to a more aggressive tumor type. Furthermore, the tumor microenvironment (tumor-associated stromal cells, extracellular matrix) plays a key role in tumorigenesis, tumor progression, and metastasis formation. Taken together, the secret for more effective cancer therapies might lie in developing and combining therapeutic strategies that also target cancer stem/progenitor cells and create an inhospitable microenvironment for highly malignant bladder cancer cells. This review will focus on the current concepts about the role of cancer stem cells, epithelial plasticity, and the supportive stroma in bladder carcinoma. The potential implications for the development of novel bladder cancer therapy will be discussed.

Emerging critical role of molecular testing in diagnostic genitourinary pathology

CONTEXT

The unprecedented advances in cancer genetics and genomics are rapidly affecting clinical management and diagnostics in solid tumor oncology. Molecular diagnostics is now an integral part of routine clinical management in patients with lung, colon, and breast cancer. In sharp contrast, molecular biomarkers have been largely excluded from current management algorithms of urologic malignancies.

OBJECTIVE

To discuss promising candidate biomarkers that may soon make their transition to the realm of clinical management of genitourologic malignancies. The need for new treatment alternatives that can improve upon the modest outcome so far in patients with several types of urologic cancer is evident. Well-validated prognostic molecular biomarkers that can help clinicians identify patients in need of early aggressive management are lacking. Identifying robust predictive biomarkers that will stratify response to emerging targeted therapeutics is another crucially needed development. A compiled review of salient studies addressing the topic could be helpful in focusing future efforts.

DATA SOURCES

A PubMed (US National Library of Medicine) search for published studies with the following search terms was conducted: molecular , prognostic , targeted therapy , genomics , theranostics and urinary bladder cancer , prostate adenocarcinoma , and renal cell carcinoma . Articles with large cohorts and multivariate analyses were given preference.

CONCLUSIONS

Our recent understanding of the complex molecular alterations involved in the development and progression of urologic malignancies is yielding novel diagnostic and prognostic molecular tools and opening the doors for experimental targeted therapies for these prevalent, frequently lethal solid tumors.

New directions for biologic targets in urothelial carcinoma

Urothelial carcinoma remains an important oncologic problem with significant morbidity and mortality. This article provides an overview of the current status of treatment of urothelial carcinoma, with an update on current trials and recent American Society of Clinical Oncology abstracts. As an alternative to focusing on the metastatic setting, we take a broad look at drug development to date, as it spans from early disease to advanced disease in the context of emerging molecular data. This approach allows us to show that each stage involves key considerations based on emerging evidence regarding molecular biology, stage-specific novel endpoints, and rational patient selection that may help further trial designs in the future. Key issues, such as neoadjuvant versus adjuvant perioperative chemotherapy, approaches to salvage second-line therapy in the metastatic setting, and treatment of elderly and cisplatin-ineligible patients, are discussed. New paradigms in clinical research, including novel endpoints, upfront rational patient selection, biomarkers, and trial design, are also addressed.

Molecular biomarkers in urothelial carcinoma of the bladder: are we there yet?

The unprecedented advances in cancer genetics and genomics are rapidly affecting the clinical management of solid tumors. Molecular diagnostics are now an integral part of routine clinical management for patients with lung, colon, and breast cancer. In sharp contrast, molecular biomarkers have been largely excluded from current management algorithms for urologic malignancies. The need for new treatment options that can improve upon the modest outcomes currently associated with muscle-invasive bladder cancer is evident, and validated prognostic molecular biomarkers that can help clinicians to identify patients in need of early, aggressive management are lacking. Robust predictive biomarkers that are able to forecast and stratify responses to emerging targeted therapies are also needed.

S6K1 and 4E-BP1 are independent regulated and control cellular growth in bladder cancer

Aberrant activation and mutation status of proteins in the phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) and the mitogen activated protein kinase (MAPK) signaling pathways have been linked to tumorigenesis in various tumors including urothelial carcinoma (UC). However, anti-tumor therapy with small molecule inhibitors against mTOR turned out to be less successful than expected. We characterized the molecular mechanism of this pathway in urothelial carcinoma by interfering with different molecular components using small chemical inhibitors and siRNA technology and analyzed effects on the molecular activation status, cell growth, proliferation and apoptosis. In a majority of tested cell lines constitutive activation of the PI3K was observed. Manipulation of mTOR or Akt expression or activity only regulated phosphorylation of S6K1 but not 4E-BP1. Instead, we provide evidence for an alternative mTOR independent but PI3K dependent regulation of 4E-BP1. Only the simultaneous inhibition of both S6K1 and 4E-BP1 suppressed cell growth efficiently. Crosstalk between PI3K and the MAPK signaling pathway is mediated via PI3K and indirect by S6K1 activity. Inhibition of MEK1/2 results in activation of Akt but not mTOR/S6K1 or 4E-BP1. Our data suggest that 4E-BP1 is a potential new target molecule and stratification marker for anti cancer therapy in UC and support the consideration of a multi-targeting approach against PI3K, mTORC1/2 and MAPK.