We chose to analyze the following four TCGA datasets because PIK3CA is frequently mutated, and PIK3R2 is overexpressed in these tumor types: colorectal cancer (COAD), bladder carcinoma (BLCA), endometrial carcinoma (UCEC), and breast cancer (BRCA) (Fig. S2a). The gene discussed is PIK3CA; the disease is urinary bladder carcinoma.