FGFR3 and p53 protein expressions in patients with pTa and pT1 urothelial bladder cancer

FGFR3 immunohistochemistry as a surrogate biomarker for FGFR3 alterations in urothelial carcinoma

FGFR3 alterations are common in urothelial carcinoma (UC) and have implications both in prognosis and treatment. FGFR3 analysis is the current gold standard, but limitations as cost, turnaround time or accessibility may exist. FGFR3 immunohistochemistry (IHC) could provide a faster and more cost-effective identification of FGFR3 alterations. The aim of this study was to establish the accuracy of FGFR3 IHC as a surrogate biomarker for FGFR3 variants in UC. We retrospectively reviewed 41 UC patients from an institutional database selected by stratified random sampling based on presence of muscle invasion and FGFR3 variants. FGFR3 genetic analysis had been stablished through quantitative polymerase chain reaction. FGFR3 IHC was performed using a FGFR3 mouse monoclonal antibody and blindly evaluated by three independent pathologists. Results were dichotomised into positive (membrane and cytoplasm positivity even in small foci of cells) or negative categories. The cohort included 37 patients with bladder cancer and four with upper tract urinary carcinoma (UTUC). Twenty-two patients had muscle-invasive tumours (11 without and 11 with FGFR3 variants), while the other 19 had non-muscle-invasive disease (10 without and 9 with FGFR3 variants). FGFR3 IHC exhibited 80 % sensitivity, 95 % specificity, 94 % PPV and 83 % NPV to detect FGFR3 variants. There was concordance among the three pathologists in 78 % of samples, which traduces a substantial agreement with a Fleiss' kappa statistic of 0.7. Our study suggests that FGFR3 IHC is feasible and could potentially eliminate the need for genetic testing in patients with positive immunohistochemical results. Our findings support a dichotomic evaluation for FGFR3 IHC, which has the potential to enhance reproducibility compared to more complex scoring systems. Still, further research is needed to validate this proposed diagnostic algorithm.

Non-muscle invasive bladder cancer biomarkers beyond morphology

Non-muscle invasive bladder cancer (NMIBC) still represents a challenge in decision-making and clinical management since prognostic and predictive biomarkers of response to treatment are still under investigation. In addition to the risk factors defined by EORTC guidelines, histological features have also been considered key variables able to impact on recurrence and progression in bladder cancer. Conversely, the role of genomic rearrangements or expression of specific proteins at tissue level need further assessment in NMIBC. As with muscle-invasive cancer, NMIBC is a heterogeneous disease, characterized by genomic instability, varying rates of mutation and a wide range of protein tissue expression. In this Review, we summarized the recent evidence on prognostic and predictive tissue biomarkers in NMIBC, beyond morphological parameters, outlining how they could affect tumor biology and consequently its behavior during clinical care. Our aim was to facilitate clinical evaluation of promising biomarkers that may be employed to better stratify patients. We described the most common molecular events and immunohistochemical protein expressions linked to recurrence and progression. Moreover, we discussed the link between available treatments and molecular drivers that could be predictive of clinical response. In conclusion, we foster further investigations with particular focus on immunohistochemical evaluation of tissue biomarkers, a promising and cost-effective tool for daily practice.

Expression of p53 Protein Associates with Anti-PD-L1 Treatment Response on Human-Derived Xenograft Model of GATA3/CR5/6-Negative Recurrent Nonmuscular Invasive Bladder Urothelial Carcinoma

BACKGROUND

The possible involvement of p53 signaling, FGFR3 expression, and FGFR3 mutation rates in the prediction of the NMIBC anti-PD-L1 treatment response needs to be clarified. The main aim of our study was to explore predictive value of p53 expression, FGFR3 expression, and its gene mutation status for the therapeutic success of anti-PD-L1 treatment in the patient-derived murine model of recurrent high-PD-L1(+) GATA3(-)/CR5/6(-) high-grade and low-grade NMIBC.

METHODS

twenty lines of patient-derived xenografts (PDXs) of relapsed high-PD-L1(+) double-negative NMIBC were developed, of which 10 lines represented high-grade tumors and the other ones-low-grade bladder cancer. Acceptors of each grade-related branch received specific anti-PD-L1 antibodies. Animals' survival, tumor-doubling time, and remote metastasis were followed during the post-interventional period. PD-L1, GATA3, CR5/6, and p53 protein expressions in engrafted tumors were assessed by immunohistochemistry. The FGFR3 expression and FGFR3 mutations in codons 248 and 249 were detected by real-time polymerase chain reaction.

RESULTS

The expression of p53 protein is an independent factor affecting the animals' survival time [HR = 0.036, p = 0.031] of anti-PD-L1-treated mice with low-grade high-PD-L1(+) double-negative NMIBC PDX. The FGFR3 expression and FGFR3 mutation rate have no impact on the anti-PD-L1 treatment response in the interventional groups.

CONCLUSIONS

p53 expression may be considered as a prognostic factor for the anti-PD-L1 treatment efficacy of low-grade high-PD-L1-positive GATA3(-)/CR5/6(-)-relapsed noninvasive bladder cancer.

The Prognostic Value of FGFR3 Expression in Patients with T1 Non-Muscle Invasive Bladder Cancer

Purpose

Fibroblast growth factor receptor 3 (FGFR3) alterations are frequent in non-muscle-invasive bladder cancer (NMIBC), although current data regarding the prognostic and therapeutic relevance are inconsistent. We analyzed the prognostic role of FGFR3 mRNA expression in stage T1 NMIBC.

Patients and Methods

The mRNA expression of FGFR3 and cyclin-dependent kinase inhibitor 2A (CDKN2A) was measured by RT-qPCR in 80 patients with stage T1 NMIBC treated with transurethral resection of the bladder and correlated with clinical data and KRT5 and KRT20 expression, used as surrogate markers for basal and luminal subtypes, respectively.

Results

FGFR3 and CDKN2A transcript levels were not correlated. FGFR3 expression was associated with the expression of KRT5 (p=0.002) and KRT20 (p < 0.001). CDKN2A expression was negatively correlated with KRT5 (p=0.030). In Kaplan–Meier analysis and univariable Cox regression analysis, high FGFR3 expression was associated with significantly reduced recurrence-free survival (RFS) (HR=3.78; p < 0.001) and improved overall survival (OS) (HR=0.50; p=0.043), while high CDKN2A expression was associated with reduced OS (HR=2.34; p=0.034). Patient age was the only clinicopathological parameter associated with reduced OS (HR=2.29; p=0.022). No parameter was an independent prognostic factor in multivariable analysis. Next, we stratified the patients depending on their lineage differentiation. In univariable analysis, the prognostic effect of FGFR3 and CDKN2A was observed primarily in patients demonstrating high expression of KRT5 or KRT20, whereas high FGFR3 expression was associated with significantly reduced RFS, irrespective of instillation therapy.

Conclusion

Stage T1 NMIBC patients with high FGFR3 expression show shorter RFS but better OS than patients with low FGFR3 expression.

Treating Bladder Cancer: Engineering of Current and Next Generation Antibody-, Fusion Protein-, mRNA-, Cell- and Viral-Based Therapeutics

Bladder cancer is a frequent malignancy and has a clinical need for new therapeutic approaches. Antibody and protein technologies came a long way in recent years and new engineering approaches were applied to generate innovative therapeutic entities with novel mechanisms of action. Furthermore, mRNA-based pharmaceuticals recently reached the market and CAR-T cells and viral-based gene therapy remain a major focus of biomedical research. This review focuses on the engineering of biologics, particularly therapeutic antibodies and their application in preclinical development and clinical trials, as well as approved monoclonal antibodies for the treatment of bladder cancer. Besides, newly emerging entities in the realm of bladder cancer like mRNA, gene therapy or cell-based therapeutics are discussed and evaluated. As many discussed molecules exhibit unique mechanisms of action based on innovative protein engineering, they reflect the next generation of cancer drugs. This review will shed light on the engineering strategies applied to develop these next generation treatments and provides deeper insights into their preclinical profiles, clinical stages, and ongoing trials. Furthermore, the distribution and expression of the targeted antigens and the intended mechanisms of action are elucidated.

Fibroblast growth factor receptor: A systematic review and meta-analysis of prognostic value and therapeutic options in patients with urothelial bladder carcinoma

To evaluate the oncologic prognostic value of fibroblast growth factor receptor (FGFR) and to assess the safety and efficacy of its inhibitors in patients with urothelial bladder carcinoma. A literature search using PubMed, Scopus, and Cochrane Library was conducted on June 2020 to identify relevant studies according to the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. The pooled recurrence-free survival (RFS), progression-free survival (PFS), and cancer-specific survival (CSS) were calculated using a fixed or random effects model in patients with nonmuscle invasive bladder cancer (NMIBC). Overall, 62 studies comprising 9,229 patients were eligible and included in this systematic review and meta-analysis. Both FGFR3 mutation and protein overexpression were significantly associated with RFS, PFS, CSS, and overall survival. FGFR3 mutation was associated with worse RFS and better PFS (pooled hazard ratio: 1.30; 95% confidence interval: 1.08-1.57, and pooled hazard ratio: 0.62; 95% confidence interval: 0.42-0.92, respectively) in patients with NMIBC. In 11 studies reporting on the response to FGFR inhibitors, complete response rates, disease control rates, and overall response rate of 0% to 8%, 59.3% to 64.2%, and 40% were reported for dovitinib, infigratinib, and erdafitinib, respectively. Based on this study, FGFR3 mutation is a statistically significant prognostic factor for RFS in NMIBC. FGFR inhibitors have measurable benefit in patients with advanced and metastatic urothelial carcinoma. However, the results of ongoing RCTs and future well-designed studies are awaited to capture the differential biologic and clinical behavior of tumors harboring FGFR while helping to identify those who are most likely to benefit from FGFR inhibitors.

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.

Fibroblast Growth Factor Receptor 3 Mutation as a Prognostic Indicator in Patients with Urothelial Carcinoma: A Systematic Review and Meta-analysis

Background

Fibroblast growth factor receptor 3 (FGFR3) mutations have been implicated in urothelial tumorigenesis. FGFR3 inhibitors are being explored in clinical trials.

Objective

We aimed to study the association between FGFR3 mutations and survival in urothelial carcinoma.

Design, setting, and participants

We performed a systematic literature search of PubMed, Cochrane, Ovid, and Web of Science from January 1985 to October 2018. The search terms were as follows: targeted therapies, FGFR and its subtypes, urothelial, bladder, and cancer. We included case-control or cohort studies of FGFR3 mutations in urothelial carcinoma. We included studies reporting hazard ratios (HRs) and 95% confidence intervals (CIs) for outcomes comparing FGFR3 mutations with FGFR3 wild type. Two reviewers performed article selection.

Outcome measurements and statistical analysis

We assessed heterogeneity among study-specific HRs using I² statistic. We used a random effect model to obtain HR and 95% CI for event-free survival (EFS), composed of recurrence-free and progression-free survival. Statistical tests were two sided.

Results and limitations

Eleven studies (seven retrospective and four prospective) comprising 2162 patients were included. Analysis was performed for two groups. The first group included 1651 patients with non–muscle-invasive (NMI) urothelial carcinomas (886 [53.6%] had FGFR3 mutations). Compared with FGFR3 wild type, FGFR3 mutation did not influence EFS (HR = 0.99, CI = 0.77–1.28, p =  0.96). There was no significant heterogeneity (I² = 25%). The second group included 511 patients with NMI and muscle-invasive (MI) urothelial carcinomas (151 [30%] had FGFR3 mutations). FGFR3 mutation was not prognostic (HR = 1.54, CI = 0.41–5.81, p =  0.52). There was heterogeneity (I² = 91%).

Conclusions

There is no association between FGFR3 mutation and EFS in NMI urothelial carcinoma, and in NMI and MI urothelial carcinoma groups.

Patient summary

Fibroblast growth factor receptor 3 (FGFR3) mutation is not associated with a worse survival outcome in urothelial carcinoma. This is important as FGFR inhibitors are emerging as a new treatment option.

Role of tyrosine kinases in bladder cancer progression: an overview

Background

Bladder cancer (BCa) is a frequent urothelial malignancy with a high ratio of morbidity and mortality. Various genetic and environmental factors are involved in BCa progression. Since, majority of BCa cases are diagnosed after macroscopic clinical symptoms, it is required to find efficient markers for the early detection. Receptor tyrosine-kinases (RTKs) and non-receptor tyrosine-kinases (nRTKs) have pivotal roles in various cellular processes such as growth, migration, differentiation, and metabolism through different signaling pathways. Tyrosine-kinase deregulations are observed during tumor progressions via mutations, amplification, and chromosomal abnormalities which introduces these factors as important candidates of anti-cancer therapies.

Main body

For the first time in present review we have summarized all of the reported tyrosine-kinases which have been significantly associated with the clinicopathological features of BCa patients.

Conclusions

This review highlights the importance of tyrosine-kinases as critical markers in early detection and therapeutic purposes among BCa patients and clarifies the molecular biology of tyrosine-kinases during BCa progression and metastasis.

FGFR3 signaling and function in triple negative breast cancer

Background

Triple negative breast cancer (TNBC) accounts for 16% of breast cancers and represents an aggressive subtype that lacks targeted therapeutic options. In this study, mass spectrometry (MS)-based tyrosine phosphorylation profiling identified aberrant FGFR3 activation in a subset of TNBC cell lines. This kinase was therefore evaluated as a potential therapeutic target.

Methods

MS-based tyrosine phosphorylation profiling was undertaken across a panel of 24 TNBC cell lines. Immunoprecipitation and Western blot were used to further characterize FGFR3 phosphorylation. Indirect immunofluorescence and confocal microscopy were used to determine FGFR3 localization. The selective FGFR1–3 inhibitor, PD173074 and siRNA knockdowns were used to characterize the functional role of FGFR3 in vitro. The TCGA and Metabric breast cancer datasets were interrogated to identify FGFR3 alterations and how they relate to breast cancer subtype and overall patient survival.

Results

High FGFR3 expression and phosphorylation were detected in SUM185PE cells, which harbor a FGFR3-TACC3 gene fusion. Low FGFR3 phosphorylation was detected in CAL51, MFM-223 and MDA-MB-231 cells. In SUM185PE cells, the FGFR3-TACC3 fusion protein contributed the majority of phosphorylated FGFR3, and largely localized to the cytoplasm and plasma membrane, with staining at the mitotic spindle in a small subset of cells. Knockdown of the FGFR3-TACC3 fusion and wildtype FGFR3 in SUM185PE cells decreased FRS2, AKT and ERK phosphorylation, and induced cell death. Knockdown of wildtype FGFR3 resulted in only a trend for decreased proliferation. PD173074 significantly decreased FRS2, AKT and ERK activation, and reduced SUM185PE cell proliferation. Cyclin A and pRb were also decreased in the presence of PD173074, while cleaved PARP was increased, indicating cell cycle arrest in G1 phase and apoptosis. Knockdown of FGFR3 in CAL51, MFM-223 and MDA-MB-231 cells had no significant effect on cell proliferation. Interrogation of public datasets revealed that increased FGFR3 expression in breast cancer was significantly associated with reduced overall survival, and that potentially oncogenic FGFR3 alterations (eg mutation and amplification) occur in the TNBC/basal, luminal A and luminal B subtypes, but are rare.

Conclusions

These results indicate that targeting FGFR3 may represent a therapeutic option for TNBC, but only for patients with oncogenic FGFR3 alterations, such as the FGFR3-TACC3 fusion.

Video abstract.

Role of FGFR3 in Urothelial Carcinoma

BACKGROUND AND OBJECTIVE

This study was undertaken to analyze the immunohistochemical expression of fibroblast growth factor receptor (FGFR3) in urothelial carcinoma and correlate its expression with the pathological stage, recurrence and other clinicopathological parameters.

MATERIAL AND METHODS

A retrospective study was undertaken on paraffin blocks of 55consecutiveurothelial carcinoma specimens in 28 months received in Sri Ramachandra Medical College, Chennai, India. Blocks with the sections containing the tumor and adjacent normal epithelium were chosen for the immunohistochemical (IHC) study of FGFR3.

RESULTS

IHC expression of FGFR3 in high grade (HG) invasive urothelial carcinoma was positive in 18% cases, 66.7% of HG non-invasive urothelial and 82.6% of low grade (LG) non-invasive urothelial carcinomas. The FGFR3 expression was presented in 78.1% of non-invasive carcinoma. In case of invasive urothelial carcinoma, the FGFR3 positivity was observed in 18.2% of tumors (P<0.05).FGFR3 expression in LG tumors was positive in 82.6 % of the cases whereas 32.3% of HG cases were positive for FGFR3 (P<0.05).FGFR3 was expressed in 14.3 % of HG invasive tumors which recurred. HG non-invasive tumors were positive for FGFR3 in 80% of the cases. LG non-invasive tumors were positive for FGFR3 in 72.7% of cases (P<0.05).

CONCLUSION

The expression of FGFR3 is higher in low grade, non-invasive tumors and recurrent non-invasive tumors. The targeted therapy for FGFR3 may be used as one of the modes of treatment for urothelial carcinoma. It can also be used as a marker to determine the grade in difficult cases and the risk of recurrence.

Low Frequency of Intratumor Heterogeneity in Bladder Cancer Tissue Microarrays

Background

Intratumoral heterogeneity (ITH) is associated with clinical challenges such as possible differences in response to treatment and difficulties in classifying the tumor. Previously, ITH has been described in bladder cancer using detailed genetic analyses. However, in this disease, it is not known to what extent ITH actually occurs, or if it involves molecular subtyping, when assessment is achieved by immunohistochemistry (IHC) on the protein level using tissue microarrays (TMAs), the method most widely applied when analyzing large sample numbers.

Objective

We aimed to investigate ITH by IHC in bladder cancer TMAs.

Methods

Staining for eleven immunohistochemical markers (CK5, Cyclin D1, E-Cadherin, EGFR, FGFR, GATA3, HER2, p16, p63, P-Cadherin and RB1) was performed, and differences in staining patterns were assessed both within 1981 individual tissue-cores and by comparing two cores from the same tumor in 948 cases according to our pre-specified criteria. Presence of ITH was associated with clinicopathological data such as stage, grade, molecular subtype and survival.

Results

Intracore ITH in one or several markers was associated with grade 3, stage T1 and the genomically unstable molecular subtype. ITH in three or more markers was found in 5% between cores (intercore heterogeneity) and in 2% within cores (intracore heterogeneity). No association with survival was found for any of the ITH groups.

Conclusions

We observed ITH in a small proportion of the tumors, suggesting that ITH has only a limited impact on TMA bladder cancer studies.

Progressive tissue biomarker profiling in non-muscle-invasive bladder cancer

INTRODUCTION

The recurrence rate of non-muscle-invasive bladder cancer (NMIBC) is up to 60% within the first year of therapy. Accurate risk stratification is necessary for patient counselling, follow-up scheduling and individualized therapeutic decision making. Current prognostic models rely on clinicopathologic features, but their discrimination remains limited when in external cohorts. Despite intense efforts regarding the value of biomarkers in prognosticating outcomes in NMIBC, clinical utility remains suboptimal. It is clear that a single biomarker is not enough for the prediction of disease recurrence. Therefore, panels of non-redundant biomarkers have been created and integrated in clinical prognostic model further research relying on high throughput technologies is required. Areas covered: We performed a systematic research of the English-language literature on tissue biomarkers for prediction of NMIBC outcomes up to December 2017. Expert commentary: Despite the essential milestones achieved in our knowledge and understanding of the molecular biology underlying NMIBC, no biomarker has been implemented together with clinical feature in clinical practice. Integration of such biomarkers into predictive and prognostic model could, however, improve our accuracy, thereby paving the way for personalized medicine in the management of NMIBC.

Urinary Bladder Cancer: Biomarkers and Target Therapy, New Era for More Attention

Currently, bladder cancer (BCa) evaluation depends mainly on traditional clinicopathological parameters encompassing tumor stage and grade, which will not reflect the behavior of the disease. Diverse molecular alterations are responsible for the heterogeneous course. The differences in molecular pathogenesis between non-invasive BCa and invasive BCa have been recognized. Molecular biomarkers are promising to predict progression and survival. The management of advanced BCa remains somewhat primitive in comparison with other more common malignancies. This topic will discuss the molecular pathways, biomarkers and potential targets that may improve the outcome in BCa.

A place for precision medicine in bladder cancer: targeting the FGFRs

Bladder tumors show diverse molecular features and clinical outcome. Muscle-invasive bladder cancer has poor prognosis and novel approaches to systemic therapy are urgently required. Non-muscle-invasive bladder cancer has good prognosis, but high recurrence rate and the requirement for life-long disease monitoring places a major burden on patients and healthcare providers. Studies of tumor tissues from both disease groups have identified frequent alterations of FGFRs, including mutations of FGFR3 and dysregulated expression of FGFR1 and FGFR3 that suggest that these may be valid therapeutic targets. We summarize current understanding of the molecular alterations affecting these receptors in bladder tumors, preclinical studies validating them as therapeutic targets, available FGFR-targeted agents and results from early clinical trials in bladder cancer patients.

Fibroblast growth factor receptor 3 protein is overexpressed in oral and oropharyngeal squamous cell carcinoma

Fibroblast growth factor receptor 3 (FGFR3) is a member of the fibroblast growth factor receptor tyrosine kinase family. It has been identified as a promising therapeutic target in multiple types of cancer. We have investigated FGFR3 protein expression and FGFR3 gene copy‐numbers in a single well‐documented cohort of oral and oropharyngeal squamous cell carcinoma. Tissue microarray sets containing 452 formalin‐fixed paraffin‐embedded tissues were immunohistochemically stained with an anti‐FGFR3 antibody and hybridized with a FGFR3 fluorescence in situ hybridization probe. FGFR3 protein expression was correlated with clinicopathological and survival data, which were retrieved from electronic medical records. FGFR3 mRNA data of 522 head and neck squamous cell carcinoma (HNSCC) were retrieved from The Cancer Genome Atlas (TCGA). Fibroblast growth factor receptor 3 (FGFR3) protein was overexpressed in 48% (89/185) of oral and 59% (124/211) of oropharyngeal squamous cell carcinoma. Overexpression of FGFR3 protein was not related to overall survival or disease‐free survival in oral (HR[hazard ratio]: 0.94; 95% CI: 0.64–1.39; P = 0.77, HR: 0.94; 95% CI: 0.65–1.36; P = 0.75) and oropharyngeal squamous cell carcinoma (HR: 1.21; 95% CI: 0.81–1.80; P = 0.36, HR: 0.42; 95% CI: 0.79–1.77; P = 0.42). FGFR3 mRNA was upregulated in 3% (18/522) of HNSCC from the TCGA. The FGFR3 gene was gained in 0.6% (1/179) of oral squamous cell carcinoma but no amplification was found in oral and oropharyngeal squamous cell carcinoma. In conclusion, FGFR3 protein is frequently overexpressed in oral and oropharyngeal squamous cell carcinoma. Therefore, it may serve as a potential therapeutic target for FGFR3‐directed therapies in oral and oropharyngeal squamous cell carcinoma.

Positive fibroblast growth factor receptor 3 immunoreactivity is associated with low-grade non-invasive urothelial bladder cancer

In addition to conventional clinicopathological parameters, molecular markers are also required in order to predict the course of disease in patients with urothelial bladder cancer (BC). Little is known about fibroblast growth factor receptor 3 (FGFR3) immunoreactivity and the clinical significance it may possess with regard to BC. The present study aimed to investigate the immunoreactivity of FGFR3 in primary urothelial bladder tumours, with regard to clinicopathological features and FGFR3 mutation status. Tissue microarrays were used to immunohistochemically analyse FGFR3 expression in 255 primary, unselected patients with BC. FGFR3 mutations were detected using SNaPshot analysis. Positive FGFR3 immunoreactivity was identified in 113/207 analysable cases (54.6%), and was significantly associated with FGFR3 mutation (P<0.001), low tumour stage (P<0.001), low histological grade (P<0.001) and a papillary growth pattern (P<0.001). Positive FGFR3 immunostaining (P=0.002) and FGFR3 mutation (P=0.002) were found to be significantly associated with increased disease-specific survival following univariate analysis, demonstrating a median follow-up period of 75 months. Using multivariate analyses, FGFR3 immunoreactivity was found not to be independent of classical pathological parameters. Immunohistochemical expression of FGFR3 is an early occurrence during the carcinogenesis of papillary non-invasive BC. The presence of FGFR3 immunoreactivity in non-invasive papillary urothelial carcinomas may be utilised as an indicator of tumours possessing low-grade features and good prognosis.

Increased angiogenesis and FGFR protein expression indicate a favourable prognosis in bladder cancer

Compared to other members of the fibroblast growth factor receptor (FGFR) family, only few studies investigate FGFR3 in tumour angiogenesis. We investigated the connection between angiogenesis and FGF/FGFR expression including FGFR3 mutation status in urothelial carcinomas. Immunohistochemistry was performed in invasive and non-invasive urothelial cancers of 61 patients. Protein expression of CD31, factor VIII (FVIII), FGF-1/2, FGFR1, FGFR3 and FGFR4 and FGFR3 mutation status were evaluated. Morphometric assessment of angiogenesis including microvessel count (MVC) and vascular surface area (VSA) was analysed. Correlation and survival analyses (overall survival (OS) and disease-free survival (DFS)) with univariate and multivariate analyses were performed. CD31 values (MVC and VSA) significantly correlated with OS and DFS. OS and DFS were significantly better in patients with FGFR3 overexpression. Multivariate analysis revealed FGFR3 protein expression and tumour grading (WHO classification 2004) as independent prognostic factors of OS and VSA of CD31 and FGFR3 protein expression of DFS. FGFR3 mutation status was correlated with VSA measured by FVIII. FGFR3 may be able to induce a pro-angiogenic phenotype in urothelial carcinomas and significantly influence prognosis. Consequently, FGFR3 is a potential therapeutic target also from the angiogenesis perspective.

Dovitinib: rationale, preclinical and early clinical data in urothelial carcinoma of the bladder

INTRODUCTION

Bladder cancer (BC) is the third and fifth cancer in men in terms of incidence and mortality in the US. Overexpression and mutations of fibroblast growth factor receptor 3 (FGFR3) are frequently found in BC and can represent a very interesting therapeutic target. Different FGFR3-targeted strategies have been investigated through in vitro and in vivo settings, including FGFR3 tyrosine kinase inhibitors such as dovitinib .

AREAS COVERED

The authors review the data that provide a scientific rationale for FGFR3-targeted therapy in BC. They also provide an evaluation of the currently available in vitro and in vivo data on the use of dovitinib in BC patients.

EXPERT OPINION

The development and progression of BC rely on a very complex signaling network that involves many different receptors aside from FGFR3 and VEGFR2. The involved signaling network can also be very different from one BC to the other, and can also evolve through time in the same patient. Inhibiting only one single target may thus not be sufficient to achieve a complete downstream oncogenic signaling blockage. Additionally, in vitro data on the use of neutralizing monoclonal antibodies targeting FGFR3 show that it can be a more efficient strategy to reach the same goal, with the potential advantage of less toxicity.

FGFR3 overexpression is prognostic of adverse outcome for muscle-invasive bladder carcinoma treated with adjuvant chemotherapy

BACKGROUND

Alterations in fibroblast growth factor receptor 3 (FGFR3) have been implicated in the pathogenesis of urothelial carcinoma. However, its clinicopathological significance has not been clearly established, especially in muscle-invasive bladder cancer (MIBC).

OBJECTIVES

The aim of our study was to investigate the mutation and overexpression of FGFR3 in MIBC cases from radical cystectomy and to analyze the prognostic and predictive significance in the groups with or without adjuvant chemotherapy.

METHODS AND MATERIALS

Study cohorts included 72 cases of MIBC including 42 patients who were treated with adjuvant chemotherapy. The mutation status of FGFR3 exons 7, 10, and 15 was investigated and protein expression was evaluated. The findings were analyzed for the association with relevant clinicopathological findings.

RESULTS

FGFR3 mutations were found in 7 patients (9.7%) and were correlated with a pattern of papillary growth, moderate histologic grade (G2 vs. G3), and moderately advanced TNM stage (II-III vs. IV). FGFR3 protein overexpression was detected in 33 cases (45.8%) but was not associated with the relevant clinicopathological parameters. In patients treated with adjuvant chemotherapy, FGFR3 overexpression was correlated with shorter disease-free survival (P = 0.067, 95% confidence interval: 14.8-29.6, marginal significance) and overall survival (P = 0.035), remaining as a significant independent prognostic factor for disease-free survival and overall survival in multivariate analysis using Cox proportional hazards model. In patients without adjuvant chemotherapy, FGFR3 mutation or overexpression did not have prognostic significance in multivariate analysis.

CONCLUSION

We report the FGFR3 alterations in MIBCs, and discuss their biological implication in subsets of patients. FGFR3 overexpression was predictive of adverse outcome in patients with adjuvant cisplatin-based chemotherapy after radical cystectomy. The utility of FGFR3 as a therapeutic target is suggested.

FGFR3 expression in primary and metastatic urothelial carcinoma of the bladder

While fibroblast growth factor receptor 3 (FGFR3) is frequently mutated or overexpressed in nonmuscle-invasive urothelial carcinoma (UC), the prevalence of FGFR3 protein expression and mutation remains unknown in muscle-invasive disease. FGFR3 protein and mRNA expression, mutational status, and copy number variation were retrospectively analyzed in 231 patients with formalin-fixed paraffin-embedded primary UCs, 33 metastases, and 14 paired primary and metastatic tumors using the following methods: immunohistochemistry, NanoString nCounterTM, OncoMap or Affymetrix OncoScanTM array, and Gain and Loss of Analysis of DNA and Genomic Identification of Significant Targets in Cancer software. FGFR3 immunohistochemistry staining was present in 29% of primary UCs and 49% of metastases and did not impact overall survival (P = 0.89, primary tumors; P = 0.78, metastases). FGFR3 mutations were observed in 2% of primary tumors and 9% of metastases. Mutant tumors expressed higher levels of FGFR3 mRNA than wild-type tumors (P < 0.001). FGFR3 copy number gain and loss were rare events in primary and metastatic tumors (0.8% each; 3.0% and 12.3%, respectively). FGFR3 immunohistochemistry staining is present in one third of primary muscle-invasive UCs and half of metastases, while FGFR3 mutations and copy number changes are relatively uncommon.

Prognostic significance of the co-overexpression of fibroblast growth factor receptors 1, 2 and 4 in gastric cancer

The overexpression of fibroblast growth factor receptor (FGFR) 2 is an established prognostic factor and treatment target in gastric cancer. However, the roles of other FGFRs have not been fully elucidated. In this study, we investigated the correlations of the expression of FGFR1-4 with clinicopathological characteristics and outcomes in gastric cancer. Tumor samples were obtained from 222 patients with gastric adenocarcinoma who underwent gastrectomy between 2003 and 2007. The expression of each FGFR was measured in the tumors by immunohistochemical analysis. The overexpression of FGFR1, FGFR2 or FGFR4 was found to be significantly associated with tumor progression, including depth of invasion, lymph node metastasis, pathological stage and distant metastasis or recurrent disease. Patients exhibiting overexpression of FGFR1, FGFR2 or FGFR4 had a significantly poorer disease-specific survival (DSS; P<0.001, P=0.008 and P<0.001, respectively). Moreover, the co-overexpression of all three FGFRs was significantly associated with a poorer DSS compared to the expression of none or only one of the FGFRs (P<0.001 and P=0.001, respectively) and it was found to be an independent prognostic factor (HR=1.71, 95% CI: 1.02-2.85, P=0.041). In conclusion, high expression of FGFR1, FGFR2 or FGFR4 was associated with tumor progression and poor survival in patients with gastric cancer. Similar to FGFR2, FGFR1 and FGFR4 may be considered as prognostic factors and treatment targets in gastric cancer.

microRNA-99a inhibiting cell proliferation, migration and invasion by targeting fibroblast growth factor receptor 3 in bladder cancer

The expression of microRNA-99a (miRNA-99a) has been investigated in a number of human cancers. It has been reported to be downregulated in several types of cancer, including ovarian carcinoma, squamous cell carcinoma of the tongue, squamous cell lung carcinoma, hepatocellular carcinoma, bladder cancer, prostate cancer and childhood adrenocortical tumors. In the present study, the effects of miRNA-99a on bladder cancer cell proliferation, migration and invasion were examined. Following transfection of miRNA-99a, cell viability, cell migration assay, cell invasion, western blot analysis and luciferase assays were conducted in bladder cancer cell lines. It was found that miRNA-99a inhibits cell proliferation, migration and invasion in T24 and EJ cells. Additionally, this study provided the first evidence that miRNA-99a is likely to directly target fibroblast growth factor receptor 3 in bladder cancer. The study provided evidence that miRNA-99a suppresses cell proliferation, migration and invasion by targeting growth factor receptor 3 in bladder cancer cell lines. These results indicated that it could be investigated as a target for therapeutic drugs designed to treat bladder cancer.

FGFR3 has tumor suppressor properties in cells with epithelial phenotype

Background

Due to frequent mutations in certain cancers, FGFR3 gene is considered as an oncogene. However, in some normal tissues, FGFR3 can limit cell growth and promote cell differentiation. Thus, FGFR3 action appears paradoxical.

Results

FGFR3 expression was forced in pancreatic cell lines. The receptor exerted dual effects: it suppressed tumor growth in pancreatic epithelial-like cells and had oncogenic properties in pancreatic mesenchymal-like cells. Distinct exclusive pathways were activated, STATs in epithelial-like cells and MAP Kinases in mesenchymal-like cells. Both FGFR3 splice variants had similar effects and used the same intracellular signaling. In human pancreatic carcinoma tissues, levels of FGFR3 dropped in tumors.

Conclusion

In tumors from epithelial origin, FGFR3 signal can limit tumor growth, explaining why the 4p16.3 locus bearing FGFR3 is frequently lost and why activating mutations of FGFR3 in benign or low grade tumors of epithelial origin are associated with good prognosis. The new hypothesis that FGFR3 can harbor both tumor suppressive and oncogenic properties is crucial in the context of targeted therapies involving specific tyrosine kinase inhibitors (TKIs). TKIs against FGFR3 might result in adverse effects if used in the wrong cell context.

Fibroblast growth factor receptor 3 is a rational therapeutic target in bladder cancer

Activating mutations of fibroblast growth factor receptor-3 (FGFR3) have been described in approximately 75% of low-grade papillary bladder tumors. In muscle-invasive disease, FGFR3 mutations are found in 20% of tumors, but overexpression of FGFR3 is observed in about half of cases. Therefore, FGFR3 is a particularly promising target for therapy in bladder cancer. Up to now, most drugs tested for inhibition of FGFR3 have been small molecule, multityrosine kinase inhibitors. More recently, a specific inhibitory monoclonal antibody targeting FGFR3 (R3Mab) has been described and tested preclinically. In this study, we have evaluated mutation and expression status of FGFR3 in 19 urothelial cancer cell lines and a cohort of 170 American patients with bladder cancer. We have shown inhibitory activity of R3Mab on tumor growth and corresponding cell signaling in three different orthotopic xenografts of bladder cancer. Our results provide the preclinical proof of principle necessary to translate FGFR3 inhibition with R3Mab into clinical trials in patients with bladder cancer.

Fibroblast growth factor receptor-3 in urothelial tumorigenesis

Fibroblast growth factor receptor-3 (FGFR3) is a receptor tyrosine kinase implicated in the tumorigenesis of multiple malignancies, including bladder and other urothelial cancers, multiple myeloma, and cervical cancer. In urothelial carcinoma (UC), constitutive receptor activation occurs most commonly through substitution of a wild-type residue with cysteine in the extracellular domain of FGFR3, thereby resulting in dimerization (through disulfide bridge formation) and subsequent stimulation of tyrosine kinase activity. Activating mutations of FGFR3 have been observed in up to 70% of non-muscle-invasive bladder tumors, while overexpression of a wild-type receptor, found in approximately 40% of tumors, has been correlated with more invasive disease. The identification of FGFR3 mutations in UC has sparked substantial interest in the therapeutic exploitation of these aberrations, and in vitro studies have provided evidence that such alterations may represent driver oncogenic lesions. In this review, we discuss the biologic and prognostic impact of FGFR3 mutations in UC as well as FGFR3 as a potential target for novel therapeutics.

Expression of regulatory proteins and proliferative activity in relation to phenotypic characteristics of upper urothelial carcinoma

BACKGROUND/AIM

Deregulation of the normal cell cycle is common in upper urothelial carcinoma (UUC). The aim of this study was to investigate the expression of regulatory proteins of the cell cycle (p53, p16, cyclin D1, HER-2) and proliferative Ki-67 activity in UUC, and to determine their interaction and influence on the phenotypic characteristics of UUC.

METHODS

In 44 patients with UUC, histopathological and immunohistochemical analyses (p53, p16, cyclin D1, HER-2, and Ki-67) of tumors were done.

RESULTS

Overexpression/altered expression of p53, p16, cyclin D1 or HER-2 was detected in 20%, 57%, 64%, and 57% of tumors, respectively. Eleven (25%) UUC had a high proliferative Ki-67 index. Forty patients (91%) had at least one marker altered, while four (9%) tumors had a wild-type status. Analysis of relationship between expressions of molecular markers showed that only high expression of p53 was significantly associated with altered p16 activity (p < 0.05). High Ki-67 index was associated with the high stage (p < 0.005), solid growth (p < 0.01), high grade (p < 0.05), and multifocality p < 0.05) of UUC, while high expression of p53 was associated with the solid growth (p < 0.05). In regression models that included all molecular markers and phenotypic characteristics, only Ki-67 correlated with the growth (p < 0.0001), stage (p < 0.01), grade (p < 0.05) and multifocality (p < 0.05) of UCC; (Ki-67 and HER-2 expression correlated with the lymphovascular invasion (p < 0.05).

CONCLUSIONS

This investigation showed that only negative regulatory proteins of the cell cycle, p53 and p16, were significantly associated in UUC, while proliferative marker Ki-67 was in relation to the key phenotypic characteristics of UUC in the best way.

Molecular markers in transitional cell carcinoma of the bladder: New insights into mechanisms and prognosis

Urothelial carcinoma is potentially life-threatening and expensive to treat since for many patients, the diagnosis entails a lifetime of surveillance to detect recurrent disease. Advancements in technology have provided an understanding of the molecular mechanisms of carcinogenesis and defined distinct pathways in tumorigenesis and progression. At the molecular level, urothelial carcinoma is being seen as a disease with distinct pathways of carcinogenesis and progression and thus markers of these processes should be used as both diagnostics and predictors of progression and patient outcome. Herein we present a selective overview of the molecular underpinning of urothelial carcinogenesis and progression and discuss the potential for proteins involved in these processes to serve as biomarkers. The discovery of biomarkers has enabled the elucidation of targets for novel therapeutic agents to disrupt the deregulation underlying the development and progression of urothelial carcinogenesis.

Can tissue microarray-based analysis of protein expression predict recurrence of stage Ta bladder cancer?

OBJECTIVE

Being able to predict the recurrence or progression of non-muscle-invasive bladder cancer would facilitate effective planning of treatments and follow-up. Biomarkers are needed that can supply prognostic information beyond that provided by clinical and pathological parameters. Tissue microarray (TMA)-based analysis of Ta bladder tumours was used to investigate the prognostic value of expression of several proteins involved in bladder carcinogenesis.

MATERIAL AND METHODS

Tumour tissue from 52 patients with Ta bladder cancer was investigated. At least three 0.6 mm punch cores from each tumour were placed in a paraffin array block. Tumour expression of tumour protein 53 (TP53), CDH1 (E-cadherin), proliferating cell nuclear antigen (PCNA), cyclooxygenase-2 (COX2), fibroblast growth factor receptor-3 (FGFR3) and epidermal growth factor receptor (EGFR) was quantified by immunohistochemistry (IHC) and correlated with time to recurrence. Median follow-up time was 3.1 years. Whole-section IHC analysis was performed to validate significant findings.

RESULTS

Of all patients, 69% (36/52) experienced recurrence. In univariate analysis, recurrence was associated with multifocality, number of earlier recurrences and a low quantity score for EGFR. In a multivariate model, a low EGFR quantity score was correlated with early recurrence (hazard ratio = 5.5, p = 0.003). However, whole-section IHC results for EGFR differed markedly from the TMA findings (κ = 0.07) and no association with time to recurrence was found (p = 0.65).

CONCLUSIONS

Expression of EGFR measured by TMA-IHC, but not by whole-section IHC, was associated with early recurrence. The results suggest that the proteins assessed have no predictive value for recurrences. Concerns are raised regarding the methodology and generalization of results obtained with TMA-IHC.

Novel targeted agents for the treatment of bladder cancer: translating laboratory advances into clinical application

Bladder cancer is a common and frequently lethal cancer. Natural history studies indicate two distinct clinical and molecular entities corresponding to invasive and non-muscle invasive disease. The high frequency of recurrence of noninvasive bladder cancer and poor survival rate of invasive bladder cancer emphasizes the need for novel therapeutic approaches. These mechanisms of tumor development and promotion in bladder cancer are strongly associated with several growth factor pathways including the fibroblast, epidermal, and the vascular endothelial growth factor pathways. In this review, efforts to translate the growing body of basic science research of novel treatments into clinical applications will be explored.

Bladder cancer or bladder cancers? Genetically distinct malignant conditions of the urothelium

Despite the fact that the current histopathologic classification for bladder cancer has led to improved concepts for the clinical management of the disease, key questions with regard to assessment of risk for recurrence and/or progression to invasive disease remain. In addition, response to specific therapies cannot be predicted accurately. Bladder tumors comprise a heterogeneous group with respect to both histopathology and clinical behavior. Thus, it is anticipated that a thorough knowledge and interpretation of the molecular alterations involved in tumor development and progression will lead to greater prognostic and predictive power. This may not only lead to better comprehension of the biology of the disease, but may also lead to the development of novel individualized therapies. Novel means of stratification are urgently needed to provide a new subclassification of urothelial lesions. This review discusses and summarizes the genetic alterations that have been reported in bladder cancer and relates these to the current 2-pathway model for tumor development. The molecular pathogenesis of high-grade noninvasive papillary tumors and of T1 tumors is not yet clear, and possibilities are discussed.

Biomarkers in bladder cancer

Cancer biomarkers provide an opportunity to diagnose tumours earlier and with greater accuracy. They can also identify those patients most at risk of disease recurrence and predict which tumours will respond to different therapeutic approaches. Such biomarkers will be especially useful in the diagnosis and management of bladder cancer. At present, bladder tumours are diagnosed and followed-up using a combination of cystoscopic examination, cytology and histology. These are not only expensive, but also highly subjective investigations and reveal little about the underlying molecular characteristics of the tumour. In recent years numerous diagnostic and prognostic biomarkers of bladder cancer have been identified. Two separate approaches to biomarker discovery have been employed. The first is hypothesis-driven and focuses upon proteins involved in molecular pathways known to be implicated in tumorigenesis. An alternative approach has been to study the global expression of genes (so-called 'genomics') looking for characteristic signatures associated with disease outcomes. In this review we summarize the current state of biomarker development in this field, and examine why so few have made the successful transition into the clinic. Finally, we introduce a novel approach to biomarker development utilizing components of the DNA replication licensing machinery.

FGFR3 mutational status and protein expression in patients with bladder cancer in a Jordanian population

Bladder cancer accounts for nearly 5% of all newly diagnosed cancers in Jordan, with a much higher frequency in males. Recent studies have shown that activating mutations in FGFR3 are the most common findings in non-invasive low grade bladder tumors. In this study, we, retrospectively, investigated a cohort of 121 bladder cancer patients with various grades and stages of the tumor for molecular changes in FGFR3. Overexpression of FGFR3 was observed in 49%, 34%, 15%, and 2% of pTa, pT1, pT2, and pT3 cases, respectively. Further, FGFR3 expression was positive in 45%, 26%, and 30% of G1, G2 and G3 cases, respectively. Mutational analysis of exons 7, 10 and 15 of FGFR3 identified four previously reported mutations, namely R248C (n=4; 10%), S249C (n=23; 59%), Y375C (n=7; 18%), G382R (n=4; 10%), and one novel mutation, G382E (n=1; 3%). Our results indicate that both mutations and overexpression of FGFR3 are correlated together, and are more prevalent in early stage (pTa and pT1) and low grade (G1 and G2) bladder tumors. Survival analysis showed no contribution of changes in FGFR3 on the patient's survival. Multivariate Cox proportional hazards model analysis of overall survival for the following variables: age, gender, stage and grade of tumor, and FGFR3 (expression and mutation) revealed that age, stage and grade of tumor are independent predictors of overall survival in patients with bladder cancer. Our work is the first to address the molecular status of FGFR3 in Jordanian patients with bladder cancer, and provides further support for FGFR3 as a key player in the initiation of bladder tumors.

Molecular genesis of non-muscle-invasive urothelial carcinoma (NMIUC)

Urothelial carcinoma (UC) is the most common type of bladder cancer in Western nations. Most patients present with the non-muscle-invasive (NMIUC) form of the disease, while up to a third harbour the invasive form (MIUC). Specifically, the aetiology of NMIUC appears to be multifactorial and very different from that of MIUC. Loss of specific tumour suppressor genes as well as gain-of-function mutations in proteins within defined cellular signalling pathways have been implicated in NMIUC aetiology. The regions of chromosome 9 that harbour CDKN2A, CDKN2B, TSC1, PTCH1 and DBC1 are frequently mutated in NMIUC, resulting in functional loss; in addition, HRAS and FGFR3, which are both proto-oncogenes encoding components of the Ras-MAPK signalling pathway, have been found to harbour activating mutations in a large number of NMIUCs. Interestingly, some of these molecular events are mutually exclusive, suggesting functional equivalence. Since several of these driving changes are amenable to therapeutic targeting, understanding the signalling events in NMIUC may offer novel approaches to manage the recurrence and progression of this disease.

Fibroblast growth factor receptor 3-IIIc mediates colorectal cancer growth and migration

Background:

Deregulation of fibroblast growth factor receptor 3 (FGFR3) is involved in several malignancies. Its role in colorectal cancer has not been assessed before.

Methods:

Expression of FGFR3 in human colorectal tumour specimens was analysed using splice variant-specific real-time reverse transcriptase PCR assays. To analyse the impact of FGFR3-IIIc expression on tumour cell biology, colon cancer cell models overexpressing wild-type (WT-3b and WT3c) or dominant-negative FGFR3 variants (KD3c and KD3b) were generated by either plasmid transfection or adenoviral transduction.

Results:

Although FGFR3 mRNA expression is downregulated in colorectal cancer, alterations mainly affected the FGFR3-IIIb splice variant, resulting in an increased IIIc/IIIb ratio predominantly in a subgroup of advanced tumours. Overexpression of WT3c increased proliferation, survival and colony formation in all colon cancer cell models tested, whereas WT3b had little activity. In addition, it conferred sensitivity to autocrine FGF18-mediated growth and migration signals in SW480 cells with low endogenous FGFR3-IIIc expression. Disruption of FGFR3-IIIc-dependent signalling by dominant-negative FGFR3-IIIc or small interfering RNA-mediated FGFR3-IIIc knockdown resulted in inhibition of cell growth and induction of apoptosis, which could not be observed when FGFR3-IIIb was blocked. In addition, KD3c expression blocked colony formation and migration and distinctly attenuated tumour growth in SCID mouse xenograft models.

Conclusion:

Our data show that FGFR3-IIIc exerts oncogenic functions by mediating FGF18 effects in colorectal cancer and may constitute a promising new target for therapeutic interventions.

Expression of fibroblast growth factor receptor 3 in the recurrence of non-muscle-invasive urothelial carcinoma of the bladder

Purpose

The fibroblast growth factor receptor 3 (FGFR3) gene is known to be frequently mutated in noninvasive urothelial carcinomas of the bladder. In this study, we investigated the expression of FGFR3, Ki-67, and p53 in bladder cancers and the effects of expression on tumor recurrence.

Materials and Methods

Fifty-five cases of primary bladder cancer were examined by immunohistochemistry. The relationship of these markers with various clinicopathological factors, including recurrence, was assessed.

Results

Positivity for cytoplasmic FGFR3 (FGFR3-c) was associated with a lower cancer grade (p=0.022) and stage (p=0.011). Recurrence was more frequent in patients with a higher stage, negative FGFR3-c, and high Ki-67 expression. According to univariate analysis, predictors of recurrence-free survival included the following: age, stage, FGFR-c, Ki-67, and p53. However, none of these was independent from the other parameters in multivariate studies.

Conclusions

The immunohistochemical expression of FGFR3 is not only one of the characteristic features of lower-grade and lower-stage urothelial carcinoma but also a possible marker in predicting disease recurrence.

Biomarkers in bladder cancer

Detailed molecular insights into bladder cancer biology might allow more detailed prognostication and optimization of treatment with the objective of improving patient outcome and quality of life. However, in bladder cancer research the search for biomarkers has been called into question and has even obtained notoriety. It is unlikely that any single marker will be able to improve prognostication for patients with bladder cancer above and beyond grade and stage, but a combination of multiple independent markers might more precisely predict the outcome. From a previous review, we identified seven biomarkers to study within the setting of the Bladder Cancer Prognosis Programme (BCPP), a 5-year multicentre programme of research based at the University of Birmingham and funded by Cancer Research UK, investigating their effectiveness in predicting recurrence and progression. As part of the ongoing quality-assurance process for BCPP we present an updated review of our selected biomarkers, as well as highlighting other recent important developments in bladder cancer research.

Utility of diagnostic and prognostic markers in urothelial carcinoma of the bladder

Urothelial carcinoma (UCC) of the bladder demonstrates diverse morphologic features, often leading to diagnostic challenges in the discrimination between UCC and benign mimickers of neoplasia, and between primary UCC and secondary neoplasms involving the bladder. In situ lesions also provide diagnostic difficulty in some instances, most prominently in the distinction between normal, reactive urothelium and flat urothelial carcinoma in situ. The use of ancillary techniques, including panels of immunohistochemical markers, in distinguishing these entities has aided not only in the diagnosis of UCC, but has also provided insight into the molecular pathogenesis and prognostic value of numerous molecular pathways in UCC. This review focuses on some of the more commonly encountered biomarkers in UCC and their role in addressing key diagnostic and prognostic issues in this disease process.

Strong immunohistochemical expression of fibroblast growth factor receptor 3, superficial staining pattern of cytokeratin 20, and low proliferative activity define those papillary urothelial neoplasms of low malignant potential that do not recur

BACKGROUND

Papillary urothelial neoplasm of low malignant potential (PUNLMP) is a clinically significant lesion because recurrence occurs in approximately 35% of patients. To date, it is not possible to identify those cases that will recur based on conventional histopathologic assessment. The objective of the current study was to evaluate immunohistochemically tissue expression of fibroblast growth factor receptor 3 (FGFR3), cytokeratin 20 (CK20), and MIB-1 in nonrecurrent and recurrent PUNLMP.

METHODS

FGFR3, CK20, and MIB-1 were investigated by immunohistochemistry (IHC) in 80 PUNLMP cases (41 nonrecurrent and 39 recurrent), in 4 cases of normal urothelium (NU), and in 5 cases of muscle invasive pT2 urothelial carcinoma (UC). Statistics included discriminant analysis.

RESULTS

NU demonstrated a weak to moderate FRFG3 staining intensity, a superficial pattern of CK20 staining, and low proliferative activity. UC was found to have FGFR3 staining similar to NU, an abnormal CK20 expression, and high proliferative activity. The nonrecurrent PUNLMP group demonstrated strong FGFR3 intensity in 80.5% of the cases (vs 56.4% of the recurrent cases), a superficial CK20 staining pattern in 53.7% of the cases (vs 28.2% of the recurrent cases), and a percentage of MIB-1-positive nuclei below the median value of all the PUNLMP cases in 61% of the cases (35.9% in the recurrent cases). The differences were statistically significant. Discriminant analysis based on these 3 features demonstrated that 67.5% of cross-validated grouped PUNLMP cases were correctly allocated, with 73.2% of the nonrecurrent and 61.5% of the nonrecurrent cases being correctly classified. The specificity and sensitivity were 73.1% and 61.5%, respectively.

CONCLUSIONS

Strong immunohistochemical expression of FGFR3, a superficial staining pattern of CK20, and a low proliferative activity define those papillary urothelial neoplasms of low malignant potential that do not recur.

Novel therapeutic targets in bladder cancer: mutation and expression of FGF receptors

Bladder cancer presents several challenges in clinical management. For the large group of noninvasive tumors, key problems are the development of multiple recurrences that require long-term surveillance and a lack of effective therapies to prevent recurrence. For the smaller group of poor prognosis patients with invasive disease, novel therapies are urgently needed. The identification of mutations of FGF receptor 3 (FGFR3) in most noninvasive bladder tumors and the recent finding of overexpression of this receptor not only in superficial tumors but also in many invasive bladder cancers has generated optimism that therapies targeting this receptor tyrosine kinase may have major application in the treatment of urothelial cancers. There is little information on the other members of this receptor family apart from FGFR2, which is implicated as a tumor suppressor. Recent preclinical evaluations of FGFR3 as a therapeutic target have provided a strong impetus for the development of targeted agents for clinical use.

Role of FGFR3 in urothelial cell carcinoma: biomarker and potential therapeutic target

Although non-invasive bladder tumours (pTa) are the most common group of bladder tumours at presentation, there has until recently been relatively little information on their molecular biology. Thus it was of great interest when mutations in the FGF receptor 3 (FGFR3) were identified in bladder tumours and it became apparent that these were most common in tumours of low grade and stage. Since the initial description of activating mutations of FGFR3, there have been numerous studies confirming the frequency and spectrum of these mutations in bladder cancers of all grades and stages. Mutation screening techniques have evolved and improved. FGFR3 mutation has been assessed as a predictive biomarker in tumour tissues and as a diagnostic biomarker in urine. Efforts have been made to understand the function of FGFR3 in urothelial and other cells. Although our understanding of FGFR3 function is incomplete, it is already apparent that this may represent an important therapeutic target not only in non-invasive bladder cancer but also in a significant number of invasive tumours. This review summarises the current state of knowledge of this interesting receptor in urothelial carcinoma (UC).

Involvement of MET/TWIST/APC combination or the potential role of ossification factors in pediatric high-grade osteosarcoma oncogenesis

Dysregulated cell growth or differentiation due to misexpression of developmental critical factors seems to be a decisive event in oncogenesis. As osteosarcomas are histologically defined by malignant osteoblasts producing an osteoid component, we prospected in pediatric osteosarcomas treated with OS94 protocol the genomic status of several genes implied in ossification processes. In 91 osteosarcoma cases, we focused on the analysis of the fibroblast growth factor receptors (FGFRs) TWIST, APC, and MET by allelotyping, real-time quantitative polymerase chain reaction, gene sequencing, and protein polymorphism study. Our study supports the frequent role of TWIST, APC, and MET as osteosarcoma markers (50%, 62%, and 50%, respectively). TWIST and MET were mainly found to be deleted, and no additional APC mutation was identified. Surprisingly, FGFRs are abnormal in only < 30%. Most of these factors and their abnormalities seem to be linked more or less to one clinical subgroup, but the most significant correlation is the link of MET, TWIST, and APC abnormalities to a worse outcome and their combination within abnormal tumors. A wider cohort is mandatory to define more robust molecular conclusions, but these results are to be considered as the beginning of a more accurate basis for diagnosis, in search of targeted therapies, and to further characterize prognostic markers.

FGFR3 protein expression and its relationship to mutation status and prognostic variables in bladder cancer

FGFR3 is frequently activated by mutation in urothelial carcinoma (UC) and represents a potential target for therapy. In multiple myeloma, both over-expression and mutation of FGFR3 contribute to tumour development. To define the population of UC patients who may benefit from FGFR-targeted therapy, we assessed both mutation and receptor over-expression in primary UCs from a population of new patients. Manual or laser capture microdissection was used to isolate pure tumour cell populations. Where present, non-invasive and invasive components in the same section were microdissected. A screen of the region of the highest tumour stage in each sample yielded a mutation frequency of 42%. Mutations comprised 61 single and five double mutations, all in hotspot codons previously identified in UC. There was a significant association of mutation with low tumour grade and stage. Subsequently, non-invasive areas from the 43 tumours with both non-invasive and invasive components were analysed separately; 18 of these had mutation in at least one region, including nine with mutation in all regions examined, eight with mutation in only the non-invasive component and one with different mutations in different regions. Of the eight with mutation in only the non-invasive component, six were predicted to represent a single tumour and two showed morphological dissimilarity of fragments within the block, indicating the possible presence of distinct tumour clones. Immunohistochemistry showed over-expression of FGFR3 protein in many tumours compared to normal bladder and ureteric controls. Increased expression was associated with mutation (85% of mutant tumours showed high-level expression). Overall, 42% of tumours with no detectable mutation showed over-expression, including many muscle-invasive tumours. This may represent a non-mutant subset of tumours in which FGFR3 signalling contributes to the transformed phenotype and which may benefit from FGFR-targeted therapies.

Knockdown by shRNA identifies S249C mutant FGFR3 as a potential therapeutic target in bladder cancer

More than 60% of low-grade non-invasive papillary urothelial cell carcinomas contain activating point mutations of fibroblast growth factor receptor 3 (FGFR3). The phenotypic consequences of constitutive activation of FGFR3 in bladder cancer have not been elucidated and further studies are required to confirm the consequences of inhibiting receptor activity in urothelial cells. We measured FGFR3 transcript levels and demonstrated that transcript levels were significantly more abundant in low-stage and grade tumours. We identified a tumour cell line, 97-7, expressing the most common FGFR3 mutation (S249C) at similar FGFR3 transcript levels to low-stage and grade tumours. In these cells, S249C FGFR3 protein formed stable homodimers and was constitutively phosphorylated. We used retrovirus-mediated delivery of shRNA to knockdown S249C FGFR3. This induced cell flattening, decreased cell proliferation and reduced clonogenicity on plastic and in soft agar. However, no effects of knockdown of wild-type FGFR3 were observed in telomerase immortalized normal human urothelial cells, indicating possible dependence of the tumour cell line on mutant FGFR3. Re-expression of S249C FGFR3 in shRNA-expressing 97-7 cells resulted in a reversal of phenotypic changes, confirming the specificity of the shRNA. These results indicate that targeted inhibition of S249C FGFR3 may represent a useful therapeutic approach in superficial bladder cancer.