FGFR3 Expression in Primary Invasive Bladder Cancers and Matched Lymph Node Metastases

The roles of FGFR3 and c-MYC in urothelial bladder cancer

Bladder cancer is one of the most frequently occurring cancers worldwide. At diagnosis, 75% of urothelial bladder cancer cases have non-muscle invasive bladder cancer while 25% have muscle invasive or metastatic disease. Aberrantly activated fibroblast growth factor receptor (FGFR)-3 has been implicated in the pathogenesis of bladder cancer. Activating mutations of FGFR3 are observed in around 70% of NMIBC cases and ~ 15% of MIBCs. Activated FGFR3 leads to ligand-independent receptor dimerization and activation of downstream signaling pathways that promote cell proliferation and survival. FGFR3 is an important therapeutic target in bladder cancer, and clinical studies have shown the benefit of FGFR inhibitors in a subset of bladder cancer patients. c-MYC is a well-known major driver of carcinogenesis and is one of the most commonly deregulated oncogenes identified in human cancers. Studies have shown that the antitumor effects of FGFR inhibition in FGFR3 dependent bladder cancer cells and other FGFR dependent cancers may be mediated through c-MYC, a key downstream effector of activated FGFR that is involved tumorigenesis. This review will summarize the current general understanding of FGFR signaling and MYC alterations in cancer, and the role of FGFR3 and MYC dysregulation in the pathogenesis of urothelial bladder cancer with the possible therapeutic implications.

Phase 3 THOR Japanese subgroup analysis: erdafitinib in advanced or metastatic urothelial cancer and fibroblast growth factor receptor alterations

BACKGROUND

In the THOR trial (NCT03390504) Cohort 1, erdafitinib demonstrated significantly prolonged overall survival (OS) (median 12.1 versus 7.8 months) and reduced risk of death by 36% (hazard ratio 0.64, P = 0.005) compared with chemotherapy in metastatic urothelial carcinoma (mUC) patients with FGFR alterations who progressed after ≥ 1 prior treatments, including anti-PD-(L)1. There have been no reports of the Japanese subgroup results yet.

METHODS

THOR Cohort 1 randomized patients to erdafitinib once daily or docetaxel/vinflunine once every 3 weeks. Primary endpoint was OS. Secondary endpoints included progression-free survival (PFS) and objective response rate (ORR). No specific statistical power was set for this Japanese subgroup analysis.

RESULTS

Of 266 patients randomized, 27 (14 erdafitinib; 13 chemotherapy) were Japanese. Baseline characteristics were generally similar between treatments and to the overall population, except for more males, lower body weight, and more upper tract primary tumors among Japanese patients. Compared with chemotherapy, erdafitinib showed improved OS (median 25.4 versus 12.4 months), PFS (median 8.4 versus 2.9 months) and ORR (57.1% versus 15.4%). Any grade treatment-related adverse events (AEs) occurred in all patients from both arms but Grade 3/4 AEs and AEs leading to discontinuation were lower in the erdafitinib arm. No new safety signals were observed in the Japanese subgroup.

CONCLUSION

In the Japanese subgroup, erdafitinib showed improved survival and response compared to chemotherapy, with no new safety concerns. These results support erdafitinib as a treatment option for Japanese mUC patients with FGFR alterations, and early FGFR testing after diagnosis of mUC should be considered.

A phase 1 study of LY3076226, a fibroblast growth factor receptor 3 (FGFR3) antibody-drug conjugate, in patients with advanced or metastatic cancer

Background We report a Phase 1 study of LY3076226, an antibody-drug conjugate composed of human IgG1 monoclonal antibody against the human FGFR3 attached with a cleavable linker to the maytansine derivative DM4 in patients with advanced or metastatic cancer. Methods This study was comprised of two parts: (A) dose escalation in patients with advanced or metastatic cancer and (B) dose expansion in patients with urothelial carcinoma with locally determined FGFR3 alterations. The dose range of LY3076226 tested was 0.2-5.0 mg/kg as an intravenous infusion on Day 1 of each 21-day cycle. The primary objective was to determine a recommended phase 2 dose (RP2D). Results Twenty-five patients were enrolled (Part A: 22, Part B: 3) and received ≥ 1 dose of LY3076226. No dose-limiting toxicities were reported. LY3076226 was generally well tolerated; most of the toxicities were Grade 1 or 2. Two patients experienced treatment-related Grade 3 toxicity (embolism and decreased platelet count). Four patients experienced serious adverse events (not treatment-related), all in Part A. Dose-proportional exposure was observed, with an estimated half-life of 2-7 days. No responses were seen with LY3076226 treatment. Stable disease persisting for > 6 months was observed in 1 patient receiving 3.2 mg/kg of LY3076226. Conclusion The study demonstrates acceptable safety and tolerability of LY3076226 up to the 5.0 mg/kg dose. Recruitment was stopped due to pipeline prioritization. Dose escalation of LY3076226 beyond 5.0 mg/kg in patients with advanced tumors may be possible. The trial was registered on August 19, 2015 under identifier NCT02529553 with ClinicalTrials.gov.

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.

Lower mutant-allele tumor heterogeneity is a biomarker in FGFR3-mutant bladder cancer for better prognosis

Background

Bladder cancer displays a broad mutational spectrum and intratumor heterogeneity (ITH), which results in difference in molecular phenotypes and resistance to therapies. However, there are currently no clinically available measures to predict patient prognosis using ITH. We aimed to establish a clinically relevant biomarker by using ITH for informing predictive of outcomes.

Methods

We used the Bioconductor R package Maftools to efficiently and comprehensively analyze somatic variants of muscle-invasive bladder cancer (MIBC) from The Cancer Genome Atlas (TCGA). We then used a mutant-allele tumor heterogeneity (MATH) algorithm to measure ITH and explored its correlation with clinical parameters as well as mutational subtypes.

Results

We observed a broad range of somatic mutations in MIBC from TCGA. MATH value was higher for the high-grade group than for the low-grade group (p < 0.05). There was a strong correlation between higher MATH value and presence of TP53 mutations (p = 0.008), as well as between lower MATH value and presence of FGFR3 mutations (p = 0.006). Patients with FGFR3 mutation and low MATH value exhibit longer overall survival time than that of all BLCA patients (p = 0.044), which was replicated in another bladder cancer database composed of 109 BLCA patients.

Conclusion

Measures of tumor heterogeneity may be useful biomarkers for identifying patients with bladder cancer. Low MATH value was an independent risk factor that predicted better prognosis for patients with FGFR3 mutation compared to all BLCA patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-020-02084-3.

Optimizing management of advanced urothelial carcinoma: A review of emerging therapies and biomarker-driven patient selection

INTRODUCTION

Advanced urothelial carcinoma has been challenging to treat due to limited treatment options, poor response rates, and poor long-term survival. New treatment options hold the promise of improved outcomes for these patients.

METHODS

A multidisciplinary working group drafted a management algorithm for advanced urothelial carcinoma using "consensus development conference" methodology. A targeted literature search identified new and emerging treatments for inclusion in the management algorithm. Published clinical data were considered during the algorithm development process, as well as the risks and benefits of the treatment options. Biomarkers to guide patient selection in clinical trials for new treatments were incorporated into the algorithm.

RESULTS

The advanced urothelial carcinoma management algorithm includes newly approved first-line anti-programmed death receptor-1 (PD1)/ programmed death-ligand 1 (PD-L1) therapies, a newly approved anti-fibroblast growth factor receptors (FGFR) therapy, and an emerging anti-Nectin 4 therapy, which have had encouraging results in phase 2 trials for second-line and third-line therapy, respectively. This algorithm also incorporates suggestions for biomarker testing of PD-L1 expression and FGFR gene alterations.

CONCLUSIONS

Newly approved and emerging therapies are starting to cover an unmet need for more treatment options, better response rates, and improved overall survival in advanced urothelial carcinoma. The management algorithm provides guidance on how to incorporate these new options, and their associated biomarkers, into clinical practice.

The future of bladder cancer therapy: Optimizing the inhibition of the fibroblast growth factor receptor

Therapeutic options for metastatic bladder cancer (BC) have seen minimal evolution over the past 30 years, with platinum-based chemotherapy remaining the mainstay of standard of care for metastatic BC. Recently, five immune checkpoint inhibitors (ICIs) have been approved by the FDA as second-line therapy, and two ICIs are approved as first-line treatment in selected patients. Molecular alterations of muscle-invasive bladder cancer (MIBC) have been reported by The Cancer Genome Atlas. About 15% of patients with MIBC have molecular alterations in the fibroblast growth factor (FGF) axis. Several ongoing trials are testing novel FGF receptor (FGFR) inhibitors in patients with FGFR genomic aberrations. Recently, erdafitinib, a pan-FGFR inhibitor, was approved by the FDA in patients with metastatic BC who have progressed on platinum-based chemotherapy. We reviewed the literature over the last decade and provide a summary of current knowledge of FGF signaling, and the prognosis associated with FGFR mutations in BC. We cover the role of FGFR inhibition with non-selective and selective tyrosine kinase inhibitors as well as novel agents in metastatic BC. Efficacy and safety data including insights from mechanism-based toxicity are reported for selected populations of metastatic BC with FGFR aberrations. Current strategies to managing resistance to anti-FGFR agents is addressed, and the importance of developing reliable biomarkers as the therapeutic landscape moves towards an individualized therapeutic approach.

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.

Small Peptide Modulation of Fibroblast Growth Factor Receptor 3-Dependent Postnatal Lymphangiogenesis

BACKGROUND

The fibroblast growth factor receptor (FGFR) family includes transmembrane receptors involved in a wide range of developmental and postdevelopmental biologic processes as well as a wide range of human diseases. In particular, FGFR3 has been implicated in the mechanism by which 9-cis retinoic acid (9-cisRA) induces lymphangiogenesis and improves lymphedema. The purpose of this study was to validate the efficacy of a novel small peptide FGFR3 inhibitor, peptide P3 (VSPPLTLGQLLS), and to elucidate the role of FGFR3 in 9-cisRA-induced lymphangiogenesis using this peptide.

METHODS AND RESULTS

Peptide P3 effectively inhibited FGFR3 phosphorylation. In vitro, peptide P3-mediated FGFR3 inhibition did not decrease lymphatic endothelial cell (LEC) proliferation, migration, or tubule formation. However, peptide P3-mediated FGFR3 inhibition did block 9-cisRA-stimulated LEC proliferation, migration, and tubule formation. In vivo, peptide P3-mediated FGFR3 inhibition was sufficient to inhibit 9-cisRA-induced tracheal lymphangiogenesis.

CONCLUSION

FGFR3 does not appear to be essential to nonpromoted LEC proliferation, migration, and tubule formation. However, FGFR3 may play a key role in LEC proliferation, migration, tubule formation, and postnatal in vivo lymphangiogenesis when pharmacologically induced by 9-cisRA. P3 may have the potential to be used as a precise regulatory control element for 9-cisRA-mediated lymphangiogenesis.

Discordant molecular subtype classification in the basal-squamous subtype of bladder tumors and matched lymph-node metastases

Molecular subtypes of muscle-invasive bladder tumors have emerged as a promising research tool with potential to stratify patients for neoadjuvant treatment. Prior to radical cystectomy, the utility of molecular classification and biomarkers depend on concordance between tissue from transurethrally resected specimens and disseminated disease. We assess the concordance of molecular subtypes and a large number of potential biomarkers in 67 pairs of muscle-invasive bladder tumors and synchronous lymph-node metastases. Tissue cores were stained for 29 immunohistochemistry markers and immunohistochemistry-based molecular subtype classification was performed. Molecular subtype was determined by mRNA profiling for 57 bladder tumors and 28 matched lymph-node metastases. Full section immunohistochemistry was performed to assess intra-tumor subtype heterogeneity in discordant cases, and exome sequencing was performed for 20 sample pairs. Discordant subtype classification between the bladder tumor and lymph-node metastasis was generally rare (12/67, 18%), but most (7/12, 58%) involved the Basal/Squamous-like subtype. Discordant Basal/Squamous-like tumors showed either Urothelial-like or Genomically Unstable, luminal-like phenotype in the lymph-node metastasis. Full section immunohistochemistry revealed intra-tumor subtype heterogeneity for six discordant cases including four involving the Basal/Squamous-like subtype. Subtype concordance for non- Basal/Squamous-like tumors was 91%. RNA-based classification agreed with immunohistochemistry classification but quantitative assessment is necessary to avoid false detection of subtype shifts. Most high confidence cancer mutations were shared between samples (n = 93, 78%), and bladder tumor private mutations (n = 20, 17%) were more frequent than those private to the lymph-node metastasis (n = 7, 6%). We conclude that bladder tumors and lymph-node metastases have overall similar molecular subtype, biomarker expression, and cancer mutations. The main exception was tumors of the Basal/Squamous-like subtype where most cases showed discordant classification, some with evidence of intra-tumor heterogeneity. The data are of relevance for neoadjuvant treatment stratification and raises questions on the dynamics of molecular subtypes during bladder cancer progression.

Different stages in drug development for muscle-invasive bladder cancer

Muscle-invasive bladder cancer (MIBC) is a highly aggressive disease. Despite optimal therapy, half of the patients will succumb to disease. This prognosis could not be improved over the last three decades. Therefore, MIBC is left behind from other cancers such as prostate, where novel treatment options were discovered and improve patient outcomes. While being aware of the recent emerging evidence of checkpoint inhibition in MIBC, we aim to describe different stages of drug development in MIBC by using three specific targets. On the example of Her2 targeting, we aimed to indicate, that either a target is ineffective in MIBC or that the patient selection is insufficient. The first clinical trials using a pan fibroblast growth factor receptor (panFGFR) inhibitor to target the FGFR pathway showed promising results. Data of further trials are to be awaited before implementing these drugs into daily clinical practice. A large variety of novel agents are investigated in vitro and in vivo. On the example of a malaria protein, we aimed to discuss a treatment paradigm that is not dependent on pathway signaling and the genomic landscape of MIBC. The ultimate question still remains to be answered: How do we select the optimal treatment for the right patient?

An integrated analysis of cancer genes in clear cell renal cell carcinoma

AIM

This study was performed to detect driver genes and implement integrated analyses on these drivers in clear cell renal cell carcinoma (ccRCC).

METHODS

Driver genes and pathways were predicted by OncodriveFM and Dendrix using 39,636 somatic mutations from The Cancer Genome Atlas, followed by DNA methylation, copy number variation, differential expression and survival analyses.

RESULTS

Overall, 342 driver genes and 106 pathways were determined by OncodriveFM, two driver genes by Dendrix. 28 driver genes were found hypomethylated, overexpressed and associated to a poor prognosis. By contrast, 17 driver genes showed decreased expression, hypermethylation and indicated a better outcome in ccRCC.

CONCLUSION

The set of new cancer genes and pathways opens the avenue for developing potential therapeutic targets and prognostic biomarkers in ccRCC.

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.

Tumor heterogeneity of fibroblast growth factor receptor 3 (FGFR3) mutations in invasive bladder cancer: implications for perioperative anti-FGFR3 treatment

BACKGROUND

Fibroblast growth factor receptor 3 (FGFR3) is an actionable target in bladder cancer. Preclinical studies show that anti-FGFR3 treatment slows down tumor growth, suggesting that this tyrosine kinase receptor is a candidate for personalized bladder cancer treatment, particularly in patients with mutated FGFR3. We addressed tumor heterogeneity in a large multicenter, multi-laboratory study, as this may have significant impact on therapeutic response.

PATIENTS AND METHODS

We evaluated possible FGFR3 heterogeneity by the PCR-SNaPshot method in the superficial and deep compartments of tumors obtained by transurethral resection (TUR, n = 61) and in radical cystectomy (RC, n = 614) specimens and corresponding cancer-positive lymph nodes (LN+, n = 201).

RESULTS

We found FGFR3 mutations in 13/34 (38%) T1 and 8/27 (30%) ≥T2-TUR samples, with 100% concordance between superficial and deeper parts in T1-TUR samples. Of eight FGFR3 mutant ≥T2-TUR samples, only 4 (50%) displayed the mutation in the deeper part. We found 67/614 (11%) FGFR3 mutations in RC specimens. FGFR3 mutation was associated with pN0 (P < 0.001) at RC. In 10/201 (5%) LN+, an FGFR3 mutation was found, all concordant with the corresponding RC specimen. In the remaining 191 cases, RC and LN+ were both wild type.

CONCLUSIONS

FGFR3 mutation status seems promising to guide decision-making on adjuvant anti-FGFR3 therapy as it appeared homogeneous in RC and LN+. Based on the results of TUR, the deep part of the tumor needs to be assessed if neoadjuvant anti-FGFR3 treatment is considered. We conclude that studies on the heterogeneity of actionable molecular targets should precede clinical trials with these drugs in the perioperative setting.

Inhibition of fibroblast growth factor receptor 3-dependent lung adenocarcinoma with a human monoclonal antibody

Activating mutations in fibroblast growth factor receptor 3 (FGFR3) have been identified in multiple types of human cancer and in congenital birth defects. In human lung cancer, fibroblast growth factor 9 (FGF9), a high-affinity ligand for FGFR3, is overexpressed in 10% of primary resected non-small cell lung cancer (NSCLC) specimens. Furthermore, in a mouse model where FGF9 can be induced in lung epithelial cells, epithelial proliferation and ensuing tumorigenesis is dependent on FGFR3. To develop new customized therapies for cancers that are dependent on FGFR3 activation, we have used this mouse model to evaluate a human monoclonal antibody (D11) with specificity for the extracellular ligand-binding domain of FGFR3, that recognizes both human and mouse forms of the receptor. Here, we show that D11 effectively inhibits signaling through FGFR3 in vitro, inhibits the growth of FGFR3-dependent FGF9-induced lung adenocarcinoma in mice, and reduces tumor-associated morbidity. Given the potency of FGF9 in this mouse model and the absolute requirement for signaling through FGFR3, this study validates the D11 antibody as a potentially useful and effective reagent for treating human cancers or other pathologies that are dependent on activation of FGFR3.

Summary: This study validates the FGF9 lung adenocarcinoma mouse model as a tool to screen and evaluate potential therapeutics that are designed to inhibit FGF9 or its target receptor, FGFR3.

FGFR3 promotes angiogenesis-dependent metastasis of hepatocellular carcinoma via facilitating MCP-1-mediated vascular formation

The biological role of fibroblast growth factor receptor 3 (FGFR3) in tumor angiogenesis of hepatocellular carcinoma (HCC) has not been discussed before. Our previous work had indicated FGFR3 was overexpressed in HCC, and silencing FGFR3 in Hu7 cells could regulate tumorigenesis via down-regulating the phosphorylation level of key members of classic signaling pathways including ERK and AKT. In the present work, we explored the role of FGFR3 in angiogenesis-dependent metastasis by using SMMC-7721 and QGY-7703 stable cell lines. Our results indicated FGFR3 could regulate in vitro cell migration ability and in vivo lung metastasis ability of HCC, which was in accordance with increased angiogenesis ability in vitro and in vivo. Using the supernatant from SMMC-7721/FGFR3 cells, we conducted a human angiogenesis protein microarray including 43 angiogenesis factors and found that FGFR3 modulated angiogenesis and metastasis of HCC mainly by promoting the protein level of monocyte chemotactic protein 1 (MCP-1). Silencing FGFR3 by short hairpin RNA (shRNA) could reduce MCP-1 level in lysates and supernatant of QGY-7703 cells and SMMC-7721 cells. Silencing MCP-1 in QGY-7703 or SMMC-7721 cells could induce similar phenotypes compared with silencing FGFR3. Our results suggested FGFR3 promoted metastasis potential of HCC, at least partially if not all, via facilitating MCP-1-mediated angiogenesis, in addition to previously found cell growth and metastasis. MCP-1, a key medium between HCC cells and HUVECs, might be a novel anti-vascular target in HCC.

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.

Fibroblast Growth Factor (FGF) Receptor/FGF Inhibitors: Novel Targets and Strategies for Optimization of Response of Solid Tumors

The fibroblast growth factor receptor (FGFR) pathway plays a major role in several biological processes, from organogenesis to metabolism homeostasis and angiogenesis. Several aberrations, including gene amplifications, point mutations, and chromosomal translocations have been described across solid tumors. Most of these molecular alterations promote multiple steps of carcinogenesis in FGFR oncogene-addicted cells, increasing cell proliferation, angiogenesis, and drug resistance. Data suggest that upregulation of FGFR signaling is a common event in many cancer types. The FGFR pathway thus arises as a potential promising target for cancer treatment. Several FGFR inhibitors are currently under development. Initial preclinical results have translated into limited successful clinical responses when first-generation, nonspecific FGFR inhibitors were evaluated in patients. The future development of selective and unselective FGFR inhibitors will rely on a better understanding of the tissue-specific role of FGFR signaling and identification of biomarkers to select those patients who will benefit the most from these drugs. Further studies are warranted to establish the predictive significance of the different FGFR-aberrations and to incorporate them into clinical algorithms, now that second-generation, selective FGFR inhibitors exist.

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.

Development and Characterization of Bladder Cancer Patient-Derived Xenografts for Molecularly Guided Targeted Therapy

BACKGROUND

The overarching goal of this project is to establish a patient-derived bladder cancer xenograft (PDX) platform, annotated with deep sequencing and patient clinical information, to accelerate the development of new treatment options for bladder cancer patients. Herein, we describe the creation, initial characterization and use of the platform for this purpose.

METHODS AND FINDINGS

Twenty-two PDXs with annotated clinical information were established from uncultured unselected clinical bladder cancer specimens in immunodeficient NSG mice. The morphological fidelity was maintained in PDXs. Whole exome sequencing revealed that PDXs and parental patient cancers shared 92-97% of genetic aberrations, including multiple druggable targets. For drug repurposing, an EGFR/HER2 dual inhibitor lapatinib was effective in PDX BL0440 (progression-free survival or PFS of 25.4 days versus 18.4 days in the control, p = 0.007), but not in PDX BL0269 (12 days versus 13 days in the control, p = 0.16) although both expressed HER2. To screen for the most effective MTT, we evaluated three drugs (lapatinib, ponatinib, and BEZ235) matched with aberrations in PDX BL0269; but only a PIK3CA inhibitor BEZ235 was effective (p<0.0001). To study the mechanisms of secondary resistance, a fibroblast growth factor receptor 3 inhibitor BGJ398 prolonged PFS of PDX BL0293 from 9.5 days of the control to 18.5 days (p<0.0001), and serial biopsies revealed that the MAPK/ERK and PIK3CA-AKT pathways were activated upon resistance. Inhibition of these pathways significantly prolonged PFS from 12 day of the control to 22 days (p = 0.001). To screen for effective chemotherapeutic drugs, four of the first six PDXs were sensitive to the cisplatin/gemcitabine combination, and chemoresistance to one drug could be overcome by the other drug.

CONCLUSION

The PDX models described here show good correlation with the patient at the genomic level and known patient response to treatment. This supports further evaluation of the PDXs for their ability to accurately predict a patient's response to new targeted and combination strategies for bladder cancer.

FGFR3 Down-Regulation is Involved in bacillus Calmette-Guérin Induced Bladder Tumor Growth Inhibition

PURPOSE

Bacillus Calmette-Guérin is the standard treatment for patients with nonmuscle invasive high histological grade bladder cancer. Previously we found that bacillus Calmette-Guérin induces murine bladder cancer MB49 cell death in vitro and in vivo, generating tissue remodeling, which involves the release of fibroblast growth factor (FGF)-2.

MATERIALS AND METHODS

We studied the effect of bacillus Calmette-Guérin treatment on FGF-2 and FGF receptor (FGFR) expression in bladder cancer.

RESULTS

In vitro FGF-2 increased MB49 cell proliferation but did not reverse bacillus Calmette-Guérin induced cell death. Increased FGF-2 expression was detected after bacillus Calmette-Guérin treatment. Moreover MB49 cells expressed high FGFR3 levels, which decreased after treatment. Similar results were observed in human T24 bladder cancer cells. In vivo MB49 tumors expressed higher FGFR3 levels than normal urothelium. Tumor FGFR3 decreased after treatment and correlated with tumor growth inhibition in response to bacillus Calmette-Guérin. In a pilot bioassay using 11 human bladder tumors treated ex vivo with bacillus Calmette-Guérin we found a subgroup of 41% of patients in whom FGFR3 was decreased after treatment.

CONCLUSIONS

Based on bladder cancer murine model results we infer that down-regulation of FGFR3 is a predictive marker of a good response to bacillus Calmette-Guérin therapy. The decrease in FGFR3 in response to bacillus Calmette-Guérin occurred not only in a murine model but also in a human bladder cancer cell line and in some patient samples. More patients and increased followup are needed to establish the predictive role of FGFR3 as a marker in human bladder cancer.

Risk based neoadjuvant chemotherapy in muscle invasive bladder cancer

Muscle invasive bladder cancer (MIBC) is an aggressive disease that frequently requires radical cystectomy (RC) to achieve durable cure rates. Surgery is most effective when performed in organ-confined disease, with the best outcomes for those patients with a pT0 result. The goals of neoadjuvant chemotherapy (NC) are to optimize surgical outcomes for a malignancy with limited adjuvant therapies and a lack of effective salvage treatments. Despite level 1 evidence demonstrating a survival benefit, the utilization of NC has been hampered by several issues, including, the inability to predict responders and the perception that NC may delay curative surgery. In this article, we review the current efforts to identify patients that are most likely to derive a benefit from NC, in order to create a risk-adapted paradigm that reserves NC for those who need it.