Chronic activation of mTORC1, secondary to inactivating mutations in TSC1 or TSC2, occurs in the syndromic tumors of TSC, as well as various malignancies, including bladder cancer (BLCA), hepatocellular cancer (HCC), renal cell carcinoma (RCC), and malignant perivascular epithelioid cell tumor (PEComa) (10–12). Here, TSC1 is linked to bladder transitional cell carcinoma.