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. Here, CYC1 is linked to urinary bladder cancer.