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

Fibroblast growth factor receptor 3 gene (FGFR3) mutations in high-grade muscle-invasive urothelial bladder cancer in a Brazilian population: evaluation and prevalence

Objective

To understand the feasibility of FGFR3 tests in the Brazilian public health context, and to sample the mutational burden of this receptor in high-grade muscle invasive bladder cancer.

Methods

A total of 31 patients with high-grade muscle-invasive bladder cancer were included in the present study. Either transurethral resection of bladder tumor or radical cystectomy specimens were analyzed. Formalin-fixed paraffin-embedded tissue blocks were sectioned, hematoxylin and eosin stained, and histologic sections were reviewed. Total RNA was extracted using the RNeasy DSP formalin-fixed paraffin-embedded kit. Qualitative results were displayed in Rotor-Gene AssayManager software.

Results

Six patients were excluded. From the samples analyzed, four (16.7%) were considered inadequate and could not have their RNA extracted. Two patients presented FGFR3 mutations, accounting for 9.5% of material available for adequate analysis. The two mutations detected included a Y373C mutation in a male patient and a S249C mutation in a female patient.

Conclusion

FGFR3 mutations could be analyzed in 84% of our cohort and occurred in 9.5% of patients with high-grade muscle invasive bladder cancer in this Brazilian population. FGFR3 gene mutations are targets for therapeutic drugs in muscle-invasive bladder cancer. For this reason, know the frequency of these mutations can have a significant impact on public health policies and costs provisioning.

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.

Molecular and Clinical Insights in Malignant Brenner Tumor of the Testis With Liver Metastases:A Case Report

Malignant Brenner Tumor (mBT) is extremely rare. Although BT are almost exclusive ovarian neoplasms, they may constitute a highly unusual tumor of the testis; in fact, only seven fully documented cases have been reported to date. Because of their rarity, the pathogenesis of these tumors has not been clarified and there is no standard therapeutic approach. We report the first case of epididymal mBT with synchronous, multiple, liver metastases and a very dramatic clinical course. Both primary tumor and metastasis were subjected to mutational analysis of 20 cancer associated genes. Primary tumor showed FGFR3 Tyr375Cys and PIK3CA His1047Arg missense mutations. Both mutations are reported as pathogenic in ClinVar database. The same FGFR3 mutation was present in liver metastasis. Based on these results we believe that the FGFR pathway could be an ideal candidate for personalized treatment, offering hope to a subset of patients with mBT. Personalized approach, including mutational analysis and molecular testing should be required in patients with rare tumors in order to clarify diagnosis and improve therapeutic strategies.

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.

MKP-1 overexpression is associated with chemoresistance in bladder cancer via the MAPK pathway

Mitogen activated protein kinase phosphatase-1 (MKP-1) has been revealed to be overexpressed in bladder cancer, particularly in non-muscle invasive bladder cancer. MKP-1 may also be associated with chemotherapy resistance. However, the underlying mechanism is yet to be elucidated. The current study investigated the expression of MKP-1 by performing immunohistochemistry in surgically resected specimens obtained from primary and recurrent patients with bladder cancer. The results revealed that MKP-1 expression increased in recurrent patients. Additionally, a 3D model of the human bladder cancer cell line, RT112, was established to determine the role of MKP-1 in drug resistance. The results demonstrated that MKP-1 overexpression protected bladder cancer cells against cell death. Contrarily, MKP-1 knockdown was revealed to sensitize cells to death. In addition, the application of MAPK inhibitors effectively increased RT112 cell sensitivity to pirarubicin. In conclusion, the results of the current study indicated that MKP-1 treatment resulted in bladder cancer cell chemoresistance via JNK, ERK and p38 pathways. MKP-1 may also serve as a potential therapeutic target for chemoresistance in patients with bladder cancer.

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.

Upregulation of FGFR3 and HIF-1α expression in muscle invasive bladder cancer

BACKGROUND The major risks in patients diagnosed with non-muscle invasive bladder cancer (NMIBC)are recurrence, progression of muscle invasive bladder cancer (MIBC), and metastasis. Biological markers such as fibroblast growth factor receptor-3 (FGFR3) and hypoxia-inducible factor-1α (HIF-1α) are related to muscle invasiveness of bladder cancer. This study was aimed to analyze the expression of FGFR3 and HIF-1α to predict muscle invasiveness in bladder cancer patients.METHODS This was an observational study with a case-control design. Sixty patients with bladder cancer, who underwent histopathology examinations at the Department of Pathology, Faculty of Medicine, Universitas Sumatera Utara/H. Adam Malik Hospital from January 2012 to December 2015, were included in this study. Samples were then classified into 30 NMIBC and 30 MIBC groups. All samples were analyzed with an immunohistochemistry assay for FGFR3 and HIF-1α. H-scores were used to determine the relationships between each group.RESULTS FGFR3 was expressed in 29 (96.7%) patients of the NMIBC group, and 23 (76.7%) patients of the MIBC group (p=0.026, OR=8.8; 95% CI=1.01–76.96). HIF-1α was expressed in only 1 (3.33%) patient of the NMIBC group, and 15 (50%) patients of the MIBC group (p<0.001, OR=29; 95% CI=3.49–241.13).CONCLUSIONS There was a difference in upregulation of FGFR3 and HIF-1α expression in both the NMIBC and MIBC groups.

Molecular investigation of FGFR3 gene mutation and its correlation with clinicopathological findings in Indian bladder cancer patients

BACKGROUND

Molecular alteration of FGFR3 gene is the most common genetic event currently known in bladder cancer. Notably, FGFR3 mutation has emerged as a promising molecular biomarker for recurrence, prognosis, and therapeutic target in bladder cancer.

AIM

The present study explored the frequency and distribution pattern of FGFR3 mutation in 100 Indian bladder cancer patients.

METHODS AND RESULTS

Exons 7, 10, and 15 were subjected to nested PCR followed by bidirectional sequencing of the PCR products. Overall, FGFR3 gene mutations were identified in 19 bladder cancer patients (19%, 19 of 100). Most of the mutations were noted in exon 7 (15%), followed by exon 10 (4%). All mutations detected were missense in nature affecting amino acids at codons 248, 249, and 373. The S249C mutations were the most recurrent mutation seen in exon 7, while Y373C was commonly observed in exon 10. In contrast to exons 7 and 10, no mutations were seen in exon 15 in this study. Females and older age patients tend to show increased frequency of FGFR3 mutations. Furthermore, FGFR3 mutations were more common in low pathological stage (6/20 pTa and 13/71 pT1) and low-grade tumors (13/46). This predominance in low-grade tumors were significantly high in comparison to high-grade tumor (P = .04). Likewise, FGFR3 mutations were significantly higher in well-differentiated tumors (32.6%, 14/43) in comparison to moderately differentiated tumors (11.3%, 5/44), and poorly differentiated tumor (0%, 0/13) (P = .007). No other association of FGFR3 with tumor size, necrosis, and variant histology was noted.

CONCLUSIONS

The current study highlights the spectrum of FGFR3 mutation in Indian patients, and the data presented here are similar to those reported from across the globe.

Fibroblast growth factor receptor (FGFR) alterations in squamous differentiated bladder cancer: a putative therapeutic target for a small subgroup

Although drugable fibroblast growth factor receptor (FGFR) alterations in squamous cell carcinomas (SCC) of various entities are well known, little is known about FGFR modifications in squamous differentiated bladder cancer. Therefore, our study evaluated FGFR1-3 alterations as a putative therapeutic target in this subgroup. We analyzed 73 squamous differentiated bladder cancers (n = 10 pT2, n = 55 pT3, n = 8 pT4) for FGFR1-3 protein expression, FGFR1-3 copy number variations, FGFR3 chromosomal rearrangements (fluorescence in situ hybridization (FISH)) and FGFR3 mutations (SNapShot analysis). Only single cases displayed enhanced protein expression, most frequently FGFR3 overexpression (9.4% (6/64)). FISH showed no amplifications of FGFR1, 2 or 3. Break apart events were only slightly above the cut off in 12.1% (8/66) of cases and no FGFR3-TACC3 rearrangements could be proven by qPCR. FGFR3 mutations (p.S249C) were found in 8.5% (6/71) of tumors and were significantly associated with FGFR3 protein overexpression (p < 0.001), and unfavourable clinical outcome (p = 0.001). Our findings are consistent with the results of the TCGA data set for the “squamous-like” subtype of bladder cancer (n = 85), which revealed reduced overall expression of FGFR1 and FGFR2 in tumors compared to normal tissue, while expression of FGFR3 remained high. In the TCGA “squamous-like” subtype FGFR3 mutations were found in 4.9% and correlated with high FGFR3 RNA expression. Mutations of FGFR1 and FGFR2 were less frequent (2.4% and 1.2%). Hence, our comprehensive study provides novel insights into a subgroup of squamous differentiated bladder tumors that hold clues for novel therapeutic regimens and may benefit from FGFR3-targeted therapies.

Evaluation of FGFR3 as a Therapeutic Target in Head and Neck Squamous Cell Carcinoma

BACKGROUND

Although head and neck squamous cell carcinoma (HNSCC) is the sixth most common tumour entity worldwide, it remains a clinical challenge. Large-scale explorative genomic projects have identified several genes as potential targets for therapy, including fibroblast growth factor receptor 3 (FGFR3).

AIMS

The aim of this study was to investigate the biological significance of wild-type and mutated FGFR3 to evaluate its potential as a novel therapeutic target in HNSCC.

METHODS

FGFR3 protein expression was analysed in a large HNSCC tissue cohort (n = 536) and FGFR3 mRNA expression from The Cancer Genome Atlas (TCGA; n = 520). Moreover, FGFR3 wild-type and mutant versions were overexpressed in vitro, and both proliferation and migration was assessed with and without BGJ398 (a specific FGFR1-3 inhibitor) treatment.

RESULTS

Although FGFR3 expression for both cohorts decreased during tumour progression, high FGFR3 expression levels were observed in a small subset of patients. In vitro, FGFR3 overexpression led to increased proliferation, whereas migration was not altered. Moreover, FGFR3-overexpressing cells were more sensitive to BGJ398. Cells overexpressing FGFR3 mutant versions showed increased proliferation compared to wild-type FGFR3 under serum-reduced conditions and were largely as sensitive as the wild-type protein to BGJ398.

CONCLUSIONS

Taken together, the results of this study demonstrate that although FGFR3 expression decreases during HNSSC progression, it plays an important role in tumour cell proliferation and thus may be a potential target for therapy in selected patients suffering from this dismal tumour entity.

Expression of FGFR3 Protein and Gene Amplification in Urinary Bladder Lesions in Relation to Schistosomiasis

BACKGROUND:

Bladder cancer represents the fifth most common malignancy worldwide and a major cause of cancer-related morbidity and death. Incidence and mortality rates have remained relatively constant over the past four decades. Urothelial bladder cancers have identified multiple risk factors.

AIM:

We aimed at evaluating the expression of the FGFR3 protein and gene amplification in the urothelial cells of neoplastic and non-neoplastic urothelial lesions of the urinary bladder, and correlation with tumour grade, stage and associated bilharziasis.

MATERIAL AND METHODS:

One hundred and five different urinary bladder lesions were studied, including 15 cystitis cases (9 bilharzial and 6 non-bilharzial cystitides), 75 urothelial carcinoma cases (18 bilharzial associated and 57 non-bilharzial associated) and 15 squamous cell carcinoma associated with bilharziasis, beside 5 control cases. Data concerning age, sex, tumour grade, stage, and associated bilharziasis were obtained. Each case was studied for FGFR3 expression, and FISH technique was applied on forty malignant cases that show high protein expression.

RESULTS:

The highest incidence of cystitis was in the fourth decade while of bladder cancer was in the seventh decade. Tumour grade was correlated significantly with tumour stage. FGFR3 correlates significantly with tumour grade, stage and with a bilharzial infestation. FGFR3 gene amplification was reported mainly in low grade and NNMBIC tumours.

CONCLUSIONS:

FGFR3 overexpression in malignant cases was significantly higher than in chronic cystitis. FGFR3 gene amplification was reported mainly in low grade and NNMBIC tumours. FGFR3 may be further studied as a subject for target therapy of bladder cancer.

Spectrum of genomic alterations in FGFR3: current appraisal of the potential role of FGFR3 in advanced urothelial carcinoma

Molecular analysis has identified subsets of urothelial carcinoma (UC) expressing distinct genetic signatures. Genomic alterations in the oncogenic fibroblast growth factor receptor 3 (FGFR3) pathway are among the most well described in UC and have led to extensive and ongoing investigation of FGFR3-targeted therapies in this disease, although no new drugs have yet been approved. Given the unmet need for effective treatments in advanced and metastatic UC, a better understanding of the known molecular alterations of FGFR3 and of the previous and ongoing clinical investigations of this promising target in UC deserves attention. The objective of the present review is to describe the landscape of alterations and biology of FGFR3 in UC, comprehensively summarize the current state of UC clinical trials of FGFR3 inhibitors, and discuss future therapeutic applications. Using the Pubmed and Clinicaltrials.gov databases, articles describing the spectrum and biological activity of FGFR3 genomic alterations and trials of FGFR3 inhibitors in UC were identified. Search terms included 'FGFR3 genomic alterations' and 'urothelial cancer' or 'bladder cancer'. Genomic alterations, including translocations and activating mutations, are increasingly described in advanced and metastatic UC. The majority of clinical trials have been performed in unselected populations; however, recent studies have reported encouraging preliminary data. We argue that routine use of molecular genomic tumour analysis in UC may inform selection of patients for appropriate trials and we further investigate the potential of FGFR3 as a meaningful clinical target for this difficult disease.

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.

TERT promoter mutations and TERT mRNA but not FGFR3 mutations are urinary biomarkers in Han Chinese patients with urothelial bladder cancer

The TERT promoter and FGFR3 gene mutations are two of the most common genetic events in urothelial bladder cancer (UBC), and these mutation assays in patient urine have been shown to be promising biomarkers for UBC diagnosis and surveillance. These results were obtained mainly from studies of patients with UBC in Western countries, and little is known about such information in Han Chinese patients with UBC. In the present study, we addressed this issue by analyzing tumors from 182 Han Chinese patients with UBC and urine samples from 102 patients for mutations in the TERT promoter and FGFR3 and TERT mRNA expression in tumors and/or urine. TERT promoter and FGFR3 mutations were identified in 87 of 182 (47.8%) and 7 of 102 (6.7%) UBC cases, respectively. In 46 urine samples from patients with TERT promoter mutation-carrying tumors, the mutant promoter was detected in 24 (52%) prior to operation and disappeared in most examined urine samples (80%) taken 1 week after operation. TERT mRNA was detected in urine derived from 46 of 49 patients (94%) that was analyzed before operation independently of the presence of TERT promoter mutations. Collectively, FGFR3 mutations occur at a very low rate in Han Chinese UBC and cannot serve as diagnostic markers for Chinese patients. Han Chinese patients with UBC have relatively low TERT promoter mutation frequency compared with patients in Western countries, and simultaneous detection of both mutant TERT promoter and TERT mRNA improves sensitivity and specificity of urine-based diagnosis.

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 mutations, but not FGFR3 expression and FGFR3 copy-number variations, are associated with favourable non-muscle invasive bladder cancer

The fibroblast growth factor receptor 3 (FGFR3) is a tyrosine kinase receptor frequently activated by point mutations in bladder cancer (BC). These mutations are associated with genetically stable, Ta and low-grade BC, representing the favourable BC pathway. Conversely, FGFR3 over-expression was recently found in 40 % of muscle invasive BC. We examined FGFR3 mutation status and protein expression in patients originally diagnosed as T1. We also investigated copy-number variations in FGFR3 as a possible alternative mechanism to activate FGFR3. We included 84 patients with T1 BC as their initial diagnosis. A uropathologist reviewed the slides for grade and (sub)stage. The FGFR3 mutation status was examined by PCR-SNaPshot and FGFR3 protein expression by standard immuno-histochemistry (FGFR3-B9). Copy-number status was determined in 69/84 cases with nine probes covering nine exons of the FGFR3 gene (MLPA). Of 27 BC with FGFR3 mutations, 26 (96 %) showed FGFR3 over-expression. Of the 57 wild-type BC, 27 (47 %) BC showed over-expression. Pathological parameters significantly differed (p < 0.01) between mutant and wild-type tumours with the FGFR3 mutation pointing to more favourable BC. However, if the BC exhibited wild-type FGFR3, FGFR3 protein status had no influence on grade and (sub)stage. We found six tumours with more than or equal to three copies of FGFR3. Only 1 of 22 wild-type tumours with over-expression of FGFR3 had more than or equal to three gene copies. In initially diagnosed T1 BC, only the FGFR3 mutation was significantly associated with favourable BC disease characteristics. In addition to almost all FGFR3 mutant BC, 47 % of wild-type BC displayed FGFR3 over-expression, suggesting an alternative mechanism to activate FGFR3. Increased FGFR3 copy number was a rare event and did not account for this mechanism. Nevertheless, FGFR3 wild-type tumours with over-expression of the protein may still represent a subset that might potentially benefit from FGFR3-targeted therapy.

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.

Expression of FGFR3 and FGFR4 and clinical risk factors associated with progression-free survival in synovial sarcoma

Although rare, synovial sarcoma (SS) is one of the most common soft tissue sarcomas affecting young adults. To investigate potential tumor markers related to synovial sarcoma prognosis, we carried out a single-institution retrospective analysis of 103 patients diagnosed with SS between 1980 and 2009. Clinical outcome data were obtained from medical records, and archived tissue samples were used to evaluate the relationship between progression-free survival (PFS) and several prognostic factors, including tumor expression of FGFR3 and FGFR4. No associations were found between PFS and gender, body mass index, tumor site, SS18-SSX translocation, or FGFR4 expression. As seen in previous studies, age at diagnosis (<35, 63% versus ≥35 years, 31% 10-year PFS; P = .033), histologic subtype (biphasic, 75% versus monophasic 34% 10-year PFS; P = .034), and tumor size (≤5 cm, 70% versus >5 cm, 22% 10-year PFS; P < .0001) were associated with PFS in SS patients. In addition, in a subset of patients with available archived tumor samples taken prior to chemotherapy or radiation (n = 34), higher FGFR3 expression was associated with improved PFS (P = .030). To the best of our knowledge, this is the largest study of SS to date to suggest a potential clinical role for FGFR3. While small numbers make this investigation somewhat exploratory, the findings merit future investigation on a larger scale.

A Decade of FGF Receptor Research in Bladder Cancer: Past, Present, and Future Challenges

Fibroblast growth factors (FGFs) orchestrate a variety of cellular functions by binding to their transmembrane tyrosine-kinase receptors (FGFRs) and activating downstream signalling pathways, including RAS/MAPK, PLCγ1, PI3K, and STATs. In the last ten years, it has become clear that FGF signalling is altered in a high proportion of bladder tumours. Activating mutations and/or overexpression of FGFR3 are common in urothelial tumours with low malignant potential and low-stage and -grade urothelial carcinomas (UCs) and are associated with a lower risk of progression and better survival in some subgroups. FGFR1 is not mutated in UC, but overexpression is frequent in all grades and stages and recent data indicate a role in urothelial epithelial-mesenchymal transition. In vitro and in vivo studies have shown that FGFR inhibition has cytotoxic and/or cytostatic effects in FGFR-dependent bladder cancer cells and FGFR-targeted agents are currently being investigated in clinical studies for the treatment of UC. Urine-based tests detecting common FGFR3 mutations are also under development for surveillance of low-grade and -stage tumours and for general population screening. Overall, FGFRs hold promise as therapeutic targets, diagnostic and prognostic markers, and screening tools for early detection and clinical management of UC.