PIK3CA and urinary bladder cancer: Twenty-four genes showed statistically significant levels of recurrent somatic mutation by analysis using MutSig (q < 0.1; Methods) (Additional file 13: Table S1), which included six well-known bladder cancer-related genes: TP53 44%, KMT2D 25%, PIK3CA 19%, ARID1A 17%, RB1 5%, and ELF3 4%.