FGFR3 Mutations in Urothelial Carcinoma: A Single-Center Study Using Next-Generation Sequencing.

Background: Mutations of fibroblast growth factor receptor 3 (FGFR3) are associated with urothelial carcinoma (UC) oncogenesis and are considered an important therapeutic target. Therefore, we evaluated the FGFR3 mutation rate and its clinical significance in urothelial carcinoma (UC) using next-generation sequencing. Methods: A total of 123 patients with UC who were treated at Chonnam National University Hospital (Gwang-ju, Korea) from January 2018 to December 2020 were enrolled. We performed NGS using the Oncomine panel with tumor specimens and blood samples corresponding to each specimen. We analyzed the FGFR3 mutation results according to the type of UC and the effects on early recurrence and progression. Results: The mean age of the patients was 71.39 ± 9.33 years, and 103 patients (83.7%) were male. Overall, the FGFR3 mutation rate was 30.1% (37 patients). The FGFR3 mutation rate was the highest in the non-muscle-invasive bladder cancer (NMIBC) group (45.1%), followed by the muscle-invasive bladder cancer (22.7%) and upper tract UC (UTUC) (14.3%) groups. Patients with FGFR3 mutations had a significantly lower disease stage (p = 0.019) but a high-risk of NMIBC (p < 0.001). Conclusions: Our results revealed that FGFR3 mutations were more prevalent in patients with NMIBC and lower stage UC and associated with a high-risk of NMIBC. Large multicenter studies are needed to clarify the clinical significance of FGFR3 mutations in UC.

Somatic Mutation of the Non-Muscle-Invasive Bladder Cancer Associated with Early Recurrence.

Next-generation sequencing (NGS) is widely used in muscle-invasive bladder cancer but has limited use in non-muscle-invasive bladder cancer (NMIBC) due to significant heterogeneity and high cancer-specific survival. Therefore, we evaluated the genomic information of NMIBC and identified molecular alterations associated with tumour recurrence. A total of 43 patients with NMIBC who underwent transurethral resection of the bladder were enrolled. We performed NGS using an Oncomine panel of tumour specimens and blood samples corresponding to each specimen. The somatic mutation results were analysed by pairwise comparison and logistic regression according to the recurrence of bladder tumours within 1 year. The median incidence of genetic variations in 43 tumour samples was 56 variations per sample, and a high tumour mutation burden (TMB) was associated with tumour recurrence (median variation 33 vs. 64, p = 0.023). The most mutated gene was adipose tissue macrophages (ATM) (79%), followed by neurofibromatosis-1 (NF1) (79%), and neurogenic locus notch homolog protein 1 (NOTCH1) (79%). In multivariable analysis, mutation of epidermal growth factor receptor (EGFR) (odds ratio [OR], 9.95; 95% confidence interval [CI], 1.40-70.96; p = 0.022) and telomerase reverse transcriptase (TERT) (OR, 7.92; 95% CI, 1.22-51.51; p = 0.030) were significant factors associated with the recurrence of bladder tumour within 1 year. Our results revealed that high TMB, EGFR mutation, and TERT mutation had a significant association with tumour recurrence in NMIBC. In addition, somatic mutations in EGFR and TERT could be useful prognostic biomarkers in NMIBC.