SIRT1 and hepatocellular carcinoma: Regarding the association between follow-up time and prognosis, high SIRT1 expression was associated with poor HCC prognosis both in studies with follow-up time <100 months (HR=2.03, 95%CI: 1.55-2.66, P<0.00001) and in studies with follow-up time≥100 months (HR=1.63, 95%CI: 1.20-2.22, P<0.002); no significant difference was observed (P=0.39).