TOP1 and urinary bladder carcinoma: For instances, SDHA and TBP in human bladder cancers [30], CYC1 and TOP1 in human brains [31], and TRAP1, FPGS and DECR1 in human PBMC samples [32], were identified as tissue HKGs that could be used as endogenous control genes, but none of them is with stable expression in corresponding tissues or cells analyzed in this study.