Zhang et al. showed that PCK1 is down-regulated by P53 in hepatocellular carcinoma and CRC cells, and that mutation of P53 directly activates expression of the NAD+-dependent histone deacetylase, sirtuin 6 (SIRT6), leading to FoxO1 deacetylation and decreased PCK1 [26]. Here, FOXO1 is linked to hepatocellular carcinoma.