SIRT1 and urinary bladder cancer: SIRT1 and SIRT3 may be up- or downregulated depending on the cancer type, acting either as oncogenes (e.g., colorectal or oral cancer) [10,11], or tumor suppressors (e.g., SIRT1 in bladder cancer, SIRT1 and SIRT3 in breast and prostate cancer) [12,13].