Mutations in PIK3CA, FGFR3, and ERBB2 highlight the relevance of the receptor tyrosine kinase (RTK)–RAS–PI3K signaling cascade in urothelial cancer pathogenesis, in line with previous studies documenting PI3K pathway alterations in 20–30% of bladder cancers [25]. The gene discussed is PIK3CA; the disease is urinary bladder carcinoma.