p63 gene expression study and early bladder carcinogenesis

Prognostic Value of P63 Expression in Muscle-Invasive Bladder Cancer and Association with Molecular Subtypes-Preliminary Report

There is an ongoing need for biomarkers that could reliably predict the outcome of BC and that could guide the management of this disease. In this setting, we aimed to explore the prognostic value of the transcription factor P63 in patients with muscle-invasive bladder cancer (MIBC) having undergone radical cystectomy. The correlation between P63 expression and clinicopathological features (tumor stage, nodes involvement, patterns of muscularis propria invasion, papillary architecture, anaplasia, concomitant carcinoma in situ, lymphovascular invasion, perineural invasion, necrosis) and molecular subtyping (basal and luminal type tumors) was tested in 65 radical cystectomy specimens and matched with cancer-specific survival (CSS) and overall survival (OS). P63-negative tumors displayed significantly higher rates of pattern 2 of muscularis propria invasion (50% vs. 14%, p = 0.002) and variant histology (45% vs. 19%, p = 0.022) compared to P63-positive ones. According to the combined expression of CK5/6 and CK20 (Algorithm #1), P63-positive and P63-negative tumors were mostly basal-like and double-negative, respectively (p = 0.004). Using Algorithm #2, based on the combined expression of CK5/6 and GATA3, the vast majority of tumors were luminal overall and in each group (p = 0.003). There was no significant difference in CSS and OS between P63-positive and P63-negative tumors, but the former featured a trend towards longer OS. Though associated with pathological features harboring negative prognostic potential, P63 status as such failed to predict CSS and OS. That said, it may contribute to better molecular subtyping of MIBC.

FGFR3 – a Central Player in Bladder Cancer Pathogenesis?

The identification of mutations in FGFR3 in bladder tumors in 1999 led to major interest in this receptor and during the subsequent 20 years much has been learnt about the mutational profiles found in bladder cancer, the phenotypes associated with these and the potential of this mutated protein as a target for therapy. Based on mutational and expression data, it is estimated that >80% of non-muscle-invasive bladder cancers (NMIBC) and ∼40% of muscle-invasive bladder cancers (MIBC) have upregulated FGFR3 signalling, and these frequencies are likely to be even higher if alternative splicing of the receptor, expression of ligands and changes in regulatory mechanisms are taken into account. Major efforts by the pharmaceutical industry have led to development of a range of agents targeting FGFR3 and other FGF receptors. Several of these have entered clinical trials, and some have presented very encouraging early results in advanced bladder cancer. Recent reviews have summarised the drugs and related clinical trials in this area. This review will summarise what is known about the effects of FGFR3 and its mutant forms in normal urothelium and bladder tumors, will suggest when and how this protein contributes to urothelial cancer pathogenesis and will highlight areas that may benefit from further study.

The interplay between Epstein-Bar virus (EBV) with the p53 and its homologs during EBV associated malignancies

p53, p63, and p73, the members of the p53 family of proteins, are structurally similar proteins that play central roles regulating cell cycle and apoptotic cell death. Alternative splicing at the carboxyl terminus and the utilization of different promoters further categorizes these proteins as having different isoforms for each. Among such isoforms, TA and ΔN versions of each protein serve as the pro and the anti-apoptotic proteins, respectively. Changes in the expression patterns of these isoforms are noted in many human cancers. Proteins of certain human herpesviruses, like Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), interact with p53 family members and alter their expressions in many malignancies. Upon infections in the B cells and epithelial cells, EBV expresses different lytic or latent proteins during viral replication and latency respectively to preserve viral copy number, chromosomal integrity and viral persistence inside the host. In this review, we have surveyed and summarised the interactions of EBV gene products, known so far, with the p53 family proteins. The interactions between P53 and EBV oncoproteins are observed in stomach cancer, non-Hodgkin's lymphoma (NHL) of the head and neck, Nasopharyngeal Cancer (NPC), Gastric carcinoma (GC) and Burkitt's lymphoma (BL). EBV latent protein EBNA1, EBNA3C, LMP-1, and lytic proteins BZLF-1 can alter p53 expressions in many cancer cell lines. Interactions of p63 with EBNA-1, 2, 5, LMP-2A and BARF-1 have also been investigated in several cancers. Similarly, associations of p73 isoform with EBV latent proteins EBNA3C and LMP-1 have been reported. Methylation and single nucleotide polymorphisms in p53 have also been found to be correlated with EBV infection. Therefore, interactions and altered expression strategies of the isoforms of p53 family proteins in EBV associated cancers propose an important field for further molecular research.

ΔNp63 transcript loss in bladder cancer constitutes an independent molecular predictor of TaT1 patients post-treatment relapse and progression

PURPOSE

Bladder cancer represents a major cause of malignancy-related morbidity and the most expensive per-patient-to-treat cancer, due to the lifelong surveillance of the patients. Accurate disease prognosis is essential in establishing personalized treatment decisions; yet optimum tools for precise risk stratification remain a competing task. In the present study, we have performed the complete evaluation of TP63 clinical significance in improving disease prognosis.

METHODS

The levels of ΔNp63 and TAp63 transcripts of TP63 were quantified in 342 bladder tissue specimens of our screening cohort (n = 182). Hedegaard et al. (Cancer Cell 30:27-42. doi:10.1016/j.ccell.2016.05.004, 2016) (n = 476) and TCGA provisional (n = 413) were used as validation cohorts for NMIBC and MIBC, respectively. Survival analysis was performed using recurrence and progression for NMIBC or mortality for MIBC as endpoint events. Bootstrap analysis was performed for internal validation, while decision curve analysis was used for the evaluation of the clinical net benefit on disease prognosis.

RESULTS

ΔNp63 was significantly expressed in bladder tissues, and was found to be over-expressed in bladder tumors. Interestingly, reduced ΔNp63 levels were correlated with muscle-invasive disease, high-grade tumors and high-EORTC-risk NMIBC patients. Moreover, ΔNp63 loss was independently associated with higher risk for NMIBC relapse (HR = 2.730; p = 0.007) and progression (HR = 7.757; p = 0.016). Hedegaard et al. and TCGA validation cohorts confirmed our findings. Finally, multivariate models combining ΔΝp63 loss with established prognostic markers led to a superior clinical benefit for NMIBC prognosis and risk stratification.

CONCLUSIONS

ΔΝp63 loss is associated with adverse outcome of NMIBC resulting in superior prediction of NMIBC early relapse and progression.

Novel therapeutic interventions for p53-altered tumors through manipulation of its family members, p63 and p73

TP53 is highly mutated in human cancers, thus targeting this tumor suppressor pathway is highly desirable and will impact many cancer patients. (1,2) Therapeutic strategies to reactivate the p53-pathway have been challenging, (3,4) and no effective treatment exists. (5) We utilized the p53-family members, p63 and p73, which are not frequently mutated in cancer, to treat p53-defective cancers. The N-terminal splice variants of p63 and p73 are denoted as the TA and ΔN isoforms. We recently demonstrated that deletion of either ΔNp63 or ΔNp73 in p53-deficient mouse tumors results in tumor regression mediated by metabolic programming. Using this strategy, we identified pramlintide, a synthetic analog of amylin, as an effective treatment for p53 deficient and mutant tumors. Here, we show the utility of using pramlintide, as a potential cancer preventive option for p53-deficient tumors in mouse models. Additionally, we found that in vivo inhibition of both ΔNp63 and ΔNp73 in combination accelerates tumor regression and increases survival of p53-deficient mice. We report that inhibition of both ΔNp63 and ΔNp73 in combination results in upregulation of 3 key metabolic regulators, IAPP, GLS2, and TIGAR resulting in an increase in apoptosis and tumor regression in ΔNp63/ΔNp73/p53 deficient thymic lymphomas. These data highlight the value of generating inhibitors that will simultaneously target ΔNp63 and ΔNp73 to treat cancer patients with alterations in p53.

Replicative study of GWAS TP63C/T, TERTC/T, and SLC14A1C/T with susceptibility to bladder cancer in North Indians

OBJECTIVE

Genome-wide association studies have confirmed association of TP63C/T rs710521, TERTC/T rs2736098, and SLC14A1C/T rs17674580 gene variants with susceptibility to bladder cancer (BC) in European and White population. However, the risk conferred for BC for above gene variants in North Indians is unknown. We therefore, studied the association of TP63C/T, TERTC/T, and SLC14A1C/T single nucleotide polymorphisms (SNPs) with a risk of BC susceptibility in North Indian cohort.

MATERIAL AND METHODS

In histologically confirmed 225 BC cases and 240 healthy controls, 3 SNPs were genotyped by real-time polymerase chain reaction. To evaluate the SNP effects on BC susceptibility, odds ratio (OR) and CI 95% were calculated.

RESULTS

In case of TP63C/T, the variant genotype (TT) showed significant reduced risk for BC (P = 0.045, OR = 0.53). Combining heterozygous and variant genotypes also demonstrated reduced risk for BC (P< 0.001, OR = 0.54). In case of TERTC/T, heterozygous genotype (CT) as well as variant genotype (TT) showed significant risk for BC susceptibility (P = 0.031, OR = 1.77 and P = 0.004, OR = 2.78, respectively) along with T allelic level (P<0.001, OR = 4.19). Furthermore, in case of SLC14A1C/T gene polymorphism, the variant genotype (TT) showed significant high risk for BC susceptibility (P = 0.006; OR = 3.01) along with variant T allelic level (P = 0.003, OR = 1.52). Interestingly, smoking was also found to modulate risks for BC in case of TERT and SLC14A1 variant genotype (TT). Further clinical confounding factor, namely, tumor grade/stage level of cases, supports the genotypic data with TERT and SLC14A1 showing a risk for BC susceptibility.

CONCLUSION

Our results suggested that polymorphism in TERTC/T and SLC14A1C/T confirmed high risk for BC in North Indian population. However, TP63C/T showed reduced risk of BC susceptibility. More replicate studies with large sample size and diverse ethnicity are required to validate these observations.

The expression of p63 in bladder cancer vs. chronic bilharzial bladder

Objective

To investigate the immunohistochemical expression of p63 in bladder cancer and the variation of expression in relation to histological type, grade and stage of the tumour, and whether bilharziasis (endemic in Egypt) has an effect on its expression, in an attempt to better understand the tumour behaviour and the possibility of using p63 as a prognostic marker.

Patients and methods

In a prospective study, biopsies were taken from the bladders of 70 patients, who were divided into three groups; group A comprised 10 with a normal urothelium, group B comprised 20 with chronic cystitis (bilharzial and non-bilharzial) and group C contained 40 with bladder cancer. The biopsies were examined for the expression of p63, using immunohistochemical techniques.

Results

The mean (SD) ages of groups A, B and C were 45.2 (9.5), 50.5 (11.7) and 60.5 (9.9) years, respectively. There was a statistically significant decrease in the expression and immunoreactivity in group C (P < 0.05), and a significant decrease with advancing tumour stage and grade (P < 0.01). In cases of squamous cell carcinoma there was a statistically significant lower immunoreactivity than in transitional cell carcinoma (P < 0.05). There was a tendency for a statistically significant decrease in the immunoreactivity in bilharzial cystitis (P < 0.05), but in the malignant group, bilharziasis had no apparent effect on the pattern of expression.

Conclusion

p63 might be a helpful biomarker and adjunct in predicting the biological behaviour and progression of tumours. Further studies are recommended to elucidate more clearly its role as a prognostic indicator and its utility as a tumour marker.

p63 steps into the limelight: crucial roles in the suppression of tumorigenesis and metastasis

The role of p63 in cancer has been an area of intense debate and controversy. Is TP63 (which encodes p63) a tumour suppressor gene or an oncogene? This debate is partly due to the complexity of the gene. There are several p63 isoforms - some with tumour suppressive functions and others with oncogenic functions. In this Opinion article, we focus on the recent advances in understanding p63 biology and its roles in cancer. In this regard, we discuss the role of p63 in multiple stem cell compartments, ageing, in the response to DNA damage and in DNA repair. Finally, we highlight the importance of understanding the interactions between all three p53 family members and the potential impact of this knowledge on cancer therapy and regenerative medicine.

Cell-cycle control in urothelial carcinoma: large-scale tissue array analysis of tumor tissue from Maine and Vermont

BACKGROUND

Cell-cycle proteins are important predictive markers in urothelial carcinoma but may also exhibit exposure-specific heterogeneity.

METHODS

Tumor tissue from 491 bladder cancer cases enrolled in the Maine and Vermont component of the New England Bladder Cancer Study was assembled as tissue microarrays and examined for aberrant expression of p53, p63, p16, cyclin D1, Rb, and Ki-67. The association between expression and histopathology, demographics, and cigarette smoking was examined using χ(2) tests, multivariable Poisson, and multinomial regression models.

RESULTS

We found that overexpression of p53 and Ki-67 was associated with high-stage/grade tumors [relative risk (RR), 1.26; P(trend) = 0.003; and RR, 3.21; P(trend) < 0.0001, respectively], whereas expression of p63 and p16 was decreased in high-stage/grade tumors (RR, 0.52; P(trend) < 0.0001; and RR, 0.88; P(trend) = 0.04, respectively). No significant aberrations of cell-cycle proteins were identified using various smoking variables and multiple statistical models.

CONCLUSION

The results of this population-based study of histologically confirmed urothelial carcinomas show significant aberration of cell-cycle proteins p53, p63, p16, and Ki-67, but not Rb or cyclin D1. p53 showed the most significant heterogeneity with respect to tumor stage and grade, especially when stratified for different staining intensities using novel digital image analysis techniques. Our findings do not support that smoking modifies expression of cell-cycle proteins.

IMPACT

Our study shows significant heterogeneity in the expression of key cell-cycle proteins that are associated with disease progression in bladder cancer. Further studies may lead to the identification of biomarkers and their multiplexed interactions as useful prognostic and therapeutic targets.

p53 Family: Role of Protein Isoforms in Human Cancer

TP53, TP63, and TP73 genes comprise the p53 family. Each gene produces protein isoforms through multiple mechanisms including extensive alternative mRNA splicing. Accumulating evidence shows that these isoforms play a critical role in the regulation of many biological processes in normal cells. Their abnormal expression contributes to tumorigenesis and has a profound effect on tumor response to curative therapy. This paper is an overview of isoform diversity in the p53 family and its role in cancer.

Distinct expression profiles of p63 variants during urothelial development and bladder cancer progression

The TP63 gene, a member of the TP53 tumor suppressor gene family, can be expressed as at least six isoforms due to alternative promoter use and alternative splicing. The lack of p63 isoform-specific antibodies has limited the analysis of the biological significance of p63. We report a novel set of well-defined antibodies to examine p63 isoforms in mouse and human urothelium during embryogenesis and tumor progression, respectively. We provide evidence that basal and intermediate urothelial cells express p63 isoforms, with the TAp63 variant the first to be detected during development, whereas umbrella cells are characterized by a p63-negative phenotype. Notably, we report that p63-null mice develop a bladder with an abnormal urothelium, constituted by a single layer of cells that express uroplakin II and low molecular weight cytokeratins, consistent with an umbrella cell phenotype. Finally, analysis of 202 human bladder carcinomas revealed a new categorization of invasive tumors into basal-like (positive for ΔNp63 and high molecular weight cytokeratins and negative for low molecular weight cytokeratins) versus luminal-like (negative for ΔNp63 and high molecular weight cytokeratins and positive for low molecular weight cytokeratins) phenotypes, with ΔNp63 expression associated with an aggressive clinical course and poor prognosis. This study highlights the relevance of p63 isoforms in both urothelial development and bladder carcinoma progression, with ΔNp63 acting as an oncogene in certain invasive bladder tumors.

Genetic susceptibility to bladder cancer risk and outcome

Bladder cancer is an excellent model for studying genetic susceptibility and gene-environment interaction in cancer etiology. The candidate gene approach found NAT2 slow acetylator and GSTM1-null genotypes to be bladder cancer susceptibility loci and also demonstrated interactions between these two genotypes and smoking in modulating bladder cancer risk. Recent genome-wide association studies identified at least eight novel genetic susceptibility loci for bladder cancer. Genetic determinants of clinical outcomes have been inconclusive. The future directions are to identify more genetic susceptibility loci for bladder cancer risk and outcome through a genome-wide association study approach, identify the causal genes and variants, study the biological mechanisms underlying the association between the causal variants and bladder cancer risk, detect gene-environment interactions and incorporate genetic knowledge into clinically applicable risk prediction models to benefit patients and public health.

[The role of the pathologist in the diagnosis of metastases from urological malignancies]

Metastases are sometimes the first revelation of urologic cancers. The role of the pathologist in case metastatic disease of unknown origin is to affirm the malignant character of the lesion; provide histological information for possible origins; and to give histological therapeutic arguments. In most of the cases the histological analysis based on cellular morphology is sufficient to suspect a particular origin. In case of poor differentiated carcinoma in addition to the histological analysis, the immunohistochemical study allows the detection of various specific antigens. In this review we approach the various morphological criteria and the interest of the various antibodies to confirm the urologic origin of a metastasis.

Gene expression study of Aurora-A reveals implication during bladder carcinogenesis and increasing values in invasive urothelial cancer

OBJECTIVES

Urothelial carcinoma is a frequent and aggressive cancer. We wanted to gain better insight into the early molecular mechanisms of bladder carcinogenesis by evaluating Aurora-A gene expression, which is implicated in genomic stability and essential for mitosis.

MATERIALS

This study, using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), analyzed the expression levels of three selected genes in dissected tissues from normal bladder, noninvasive cancers, and muscle-invasive bladder carcinomas (n = 49). We compared gene expression levels of three genes (Aurora-A, and as control uroplakin II (UPII) and TBP, respectively) at different stages of bladder cancer. We used multivariate analysis, receiver operating characteristic curves and the nonparametric Mann-Whitney test.

RESULTS

The expression of Aurora-A gene studied was significantly deregulated, with an increasing level in cancer versus normal tissue Aurora-A. This development was linear. Aurora-A was already deregulated in early stages of carcinogenesis (pTa/pT1) (P = 0.0004) and displayed even more deregulation in muscle-invasive stages (pT2 to pT4). Immunohistochemistry performed on the same samples using Aurora-A antibody confirmed results of RT-PCR, with statistically significant values when comparing m-RNA expression and immunohistochemical values (P = 0.0001).

CONCLUSIONS

This study highlights the fact that Aurora-A gene expression is already strongly deregulated in early stages of urothelial carcinoma with abnormal expression, and might be considered a biomarker of tumor aggression. The increase in Aurora-A expression might provide further information regarding the behavior of bladder cancer in daily practice.