Prognostic Value and Clinical Significance of FGFR Genomic Alterations (GAs) in Metastatic Urothelial Cancer Patients

Development and deployment of a histopathology-based deep learning algorithm for patient prescreening in a clinical trial

Accurate identification of genetic alterations in tumors, such as Fibroblast Growth Factor Receptor, is crucial for treating with targeted therapies; however, molecular testing can delay patient care due to the time and tissue required. Successful development, validation, and deployment of an AI-based, biomarker-detection algorithm could reduce screening cost and accelerate patient recruitment. Here, we develop a deep-learning algorithm using >3000 H&E-stained whole slide images from patients with advanced urothelial cancers, optimized for high sensitivity to avoid ruling out trial-eligible patients. The algorithm is validated on a dataset of 350 patients, achieving an area under the curve of 0.75, specificity of 31.8% at 88.7% sensitivity, and projected 28.7% reduction in molecular testing. We successfully deploy the system in a non-interventional study comprising 89 global study clinical sites and demonstrate its potential to prioritize/deprioritize molecular testing resources and provide substantial cost savings in the drug development and clinical settings.

Do Fibroblast Growth Factor Receptor (FGFR) 2 and 3 Proteins Play a Role in Prognosis of Invasive Urothelial Bladder Carcinoma?

Background & Objective

Bladder carcinoma ranks second in prevalence among males in Egypt. As a family of tyrosine kinases, fibroblast growth factor receptor (FGFR) dysregulation has been linked to some malignancies in humans. The aim of this study is to analyze the clinicopathological data of patients while investigating FGFR2 and FGFR3 immunohistochemical expression in invasive urothelial bladder carcinoma.

Methods

This retrospective cross-sectional study included 60 invasive urothelial carcinoma (UC) cases in the Pathology department, Faculty of Medicine, Menoufia University, from 2009 to 2020. All biopsies were stained for FGFR2 and FGFR3 antibodies. Complete clinical data were available for 44 patients treated and followed in clinical oncology and nuclear medicine departments.

Results

Advanced stage and high grade are significantly correlated with FGFR2 positivity (P=0.048 and 0.044, respectively). Cases presented with Perineural invasion showed a higher percentage of FGFR2 (P=0.023). There is a significant indirect linear correlation between FGFR3 expression and lymph node positivity (r= -0.265, P=0.041).

Conclusion

A high FGFR2 expression could be associated with poor prognostic parameters, while high FGFR3 expression would be associated with good prognostic parameters. These findings might highlight the importance of FGFR-targeted therapy as a FGFR2 antagonist and FGFR3 agonist for the treatment of urothelial carcinoma patients.

Urothelial Bladder Cancer: Genomic Alterations in Fibroblast Growth Factor Receptor

BACKGROUND AND OBJECTIVE

Genomic alterations in fibroblast growth factor receptor (FGFR) genes have been linked to a reduced response to immune checkpoint inhibitors. Some of the immune microenvironment of urothelial bladder cancer (UBC) could be distorted because of the inhibition of interferon signaling pathways. We present a landscape of FGFR genomic alterations in distorted UBC to evaluate the immunogenomic mechanisms of resistance and response.

METHODS

There were 4035 UBCs that underwent hybrid, capture-based comprehensive genomic profiling. Tumor mutational burden was determined in up to 1.1 Mbp of sequenced DNA and microsatellite instability was determined in 114 loci. Programmed death ligand expression in tumor cells was assessed by immunohistochemistry (Dako 22C3).

RESULTS

The FGFR tyrosine kinases were altered in 894 (22%) UBCs. The highest frequency of alterations was in FGFR genomic alterations with FGFR3 at 17.4% followed by FGFR1 at 3.7% and FGFR2 at 1.1%. No FGFR4 genomic alterations were identified. The age and sex distribution were similar in all groups. Urothelial bladder cancers that featured FGFR3 genomic alterations were associated with lower driver genomic alterations/tumors. 14.7% of the FGFR3 genomic alterations were FGFR3 fusions. Other findings included a significantly higher frequency of ERBB2 amplification in FGFR1/2-altered UBCs compared with FGFR3-altered UBCs. Urothelial bladder cancers with FGFR3 genomic alterations also had the highest frequency of the activating mTOR pathway. FGFR3-altered UBCs also featured significantly higher frequencies of biomarkers associated with a lack of response to immune checkpoint inhibitors including a lower tumor mutational burden, lower programmed death-ligand 1 expression, and higher frequencies of genomic alterations in MDM2. Also linked to IO drug resistance, CDKN2A/B loss and MTAP loss were observed at a higher frequency in FGFR3-driven UBC.

CONCLUSIONS

An increased frequency of genomic alterations is observed in UBC FGFR. These have been linked to immune checkpoint inhibitor resistance. Clinical trials are needed to evaluate UBC FGFR-based biomarkers prognostic of an immune checkpoint inhibitor response. Only then can we successfully incorporate novel therapeutic strategies into the evolving landscape of UBC treatment.

Stellettin B Induces Cell Death in Bladder Cancer Via Activating the Autophagy/DAPK2/Apoptosis Signaling Cascade

Bladder cancer (BC) is one of the most prevalent cancers worldwide. However, the recurrence rate and five-year survival rate have not been significantly improved in advanced BC, and new therapeutic strategies are urgently needed. The anticancer activity of stellettin B (SP-2), a triterpene isolated from the marine sponge Rhabdastrella sp., was evaluated with the MTT assay as well as PI and Annexin V/7-AAD staining. Detailed mechanisms were elucidated through an NGS analysis, protein arrays, and Western blotting. SP-2 suppressed the viability of BC cells without severe toxicity towards normal uroepithelial cells, and it increased apoptosis with the activation of caspase 3/8/9, PARP, and γH2AX. The phosphorylation of FGFR3 and its downstream targets were downregulated by SP-2. Meanwhile, it induced autophagy in BC cells as evidenced by LC3-II formation and p62 downregulation. The inhibition of autophagy using pharmacological inhibitors or through an ATG5-knockout protected RT-112 cells from SP-2-induced cell viability suppression and apoptosis. In addition, the upregulation of DAPK2 mRNA and protein expression also contributed to SP-2-induced cytotoxicity and apoptosis. In RT-112 cells, an FGFR3-TACC3-knockout caused the downregulation of DAPK2, autophagy, and apoptosis. In conclusion, this is the first study demonstrating that SP-2 exhibits potent anti-BC activity by suppressing the FGFR3-TACC3/Akt/mTOR pathway, which further activates a novel autophagy/DAPK2/apoptosis signaling cascade.

Correlation between fibroblast growth factor receptor mutation, programmed death ligand-1 expression and survival in urinary bladder cancer based on real-world data

Background: Programmed cell death (PD)-1/PD-ligand 1 (PD-L1) inhibitors have made a breakthrough in the therapy of advanced urothelial bladder cancer (UBC). The impact of Fibroblast Growth Factor Receptor 3 (FGFR3) mutation on the effectiveness of PD-L1 treatment remains still unclear. Objective: Our study aimed to investigate the frequency of FGFR mutations at different tumor stages, and their relation to PD-L1 status and survival. Methods: 310 patients with urothelial bladder cancer and subsequent radical cystectomy were included in a retrospective study over a 10-year study period at the University of Szeged, Hungary. FGFR3 mutations from the most infiltrative areas of the tumor were analyzed by targeted next-generation sequencing and PD-L1 (28-8 DAKO) tests (tumor positive score -TPS and combined positives score-CPS). In T0 cases FGFR3 mutations were analyzed from the earlier resection samples. Survival and oncological treatment data were collected from the National Health Insurance Fund (NHIF). Neoadjuvant, adjuvant and palliative conventional chemotherapies were allowed; immunotherapies were not. The relationship between the covariates was tested using chi-square tests, and survival analysis was performed using the Kaplan-Meier model and Cox proportional hazards regression. Results: PD-L1 and FGFR could be tested successfully in 215 of the 310 UBC samples [pT0_cyst 19 (8.8%); St.0-I 43 (20%); St.II 41 (19%); St.III-IV 112 (52%)]. Significant pairwise dependency was found between tumor stage, FGFR3 mutation status and PD-L1 expression (p < 0.01). Samples with FGFR mutation were more common in less advanced stages and were also less likely to demonstrate PD-L1 expression. The effect of all investigated factors on survival was found to correlate with tumor stage. Conclusion: FGFR alteration frequency varied between the different stages of cancer. Higher positivity rates were observed at early stages, but lower levels of PD-L1 expression were detected in patients with FGFR mutations across at all stages of the disease.

Patient Selection Approaches in FGFR Inhibitor Trials-Many Paths to the Same End?

Inhibitors of fibroblast growth factor receptor (FGFR) signaling have been investigated in various human cancer diseases. Recently, the first compounds received FDA approval in biomarker-selected patient populations. Different approaches and technologies have been applied in clinical trials, ranging from protein (immunohistochemistry) to mRNA expression (e.g., RNA in situ hybridization) and to detection of various DNA alterations (e.g., copy number variations, mutations, gene fusions). We review, here, the advantages and limitations of the different technologies and discuss the importance of tissue and disease context in identifying the best predictive biomarker for FGFR targeting therapies.