FGFR3 expression in primary invasive bladder cancers and matched lymph node metastases.

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapeutics

Background:

• Fibroblast growth factor receptor 3 (FGFR3) is a promising therapeutic target in bladder cancer.
• The concordance of FGFR3 status between primary bladder tumors and metastases is not well-established.
• Understanding this concordance is crucial for guiding systemic FGFR-targeted therapies.

Purpose of the Study:

• To assess the concordance of FGFR3 protein expression between primary bladder tumors and matched nodal metastases.
• To determine if primary tumor FGFR3 status can serve as a surrogate for metastatic lesions.
• To evaluate the potential of FGFR3 status in guiding FGFR-targeted therapy selection.

Main Methods:

• Analysis of matched primary tumor and nodal metastasis samples from 150 bladder cancer patients (N0M0 stage).
• Tissue microarray construction with four samples per patient.
• Immunohistochemistry used to assess FGFR3 protein expression.
• Statistical analysis including Fisher exact test and Kaplan-Meier survival analysis.

Main Results:

• High concordance (OR 8.6-16.7, p <0.001) was observed between FGFR3 expression in primary tumors and matched lymph node metastases.
• FGFR3 protein expression levels did not significantly differ between primary and metastatic lesions (p = 0.78).
• While generally concordant, a subset of patients showed discordant FGFR3 expression in either the primary tumor or metastases alone.

Conclusions:

• FGFR3 expression in matched primary and metastatic bladder cancer specimens demonstrates good, though not absolute, concordance.
• Primary tumor FGFR3 status is a reliable indicator for selecting FGFR-targeted therapies in the majority of bladder cancer patients.
• These findings support the use of primary tumor biopsy data for treatment decisions in advanced bladder cancer.