Comprehensive genome-wide association study into multiple recurrence and progression risk in non-muscle invasive bladder cancer

ABSTRACT Background Patients with non-muscle invasive bladder cancer (NMIBC) frequently experience recurrence and may progress to muscle-invasive disease. Although several common germline variants associated with bladder cancer risk have been identified, their prognostic value in NMIBC remains unclear. We performed an updated genome-wide association study (GWAS), incorporating additional cohorts and analysing multiple NMIBC recurrences, to identify germline genetic variants associated with recurrence and progression. Methods We analysed eight cohorts (N = 5,009) from the Netherlands, UK, Canada, and Spain. Cohort-specific GWAS were conducted using Cox regression for recurrence-free survival (RFS) and progression-free survival (PFS), including recurrent-event analysis and gene-based analyses. Analyses included chromosome X and were stratified by sex and Bacillus Calmette-Guérin (BCG) treatment. Previously reported variants for bladder cancer risk and prognosis were also evaluated. Results We observed 4,237 recurrences, of which 2,145 were first recurrences, and 742 cases of progression in stage and/or grade. No genome-wide significant associations were identified in the overall population, chromosome X, or sex-stratified analyses. In BCG-treated patients, two loci reached genome-wide significance for RFS, with the strongest signal for rs72744118, an intron variant in DISP-1 (HR = 0.43; 95% CI (0.32, 0.56), p = 5.8 × 10 -10 ). Gene prioritization identified 101 candidate genes from SNP associations (p < 1 × 10 -6 ) and colocalization analyses, of which 16 genes showed nominally significant association between gene expression and NMIBC outcome in UROMOL. Conclusions In the largest GWAS of NMIBC prognosis to date, we prioritized a set of 16 genes. Future research should independently validate the prognostic and functional roles of identified genes.