FOXO1 and hepatocellular carcinoma: In fact, interleukin 15 (IL15) produced in the hepatic microenvironment downregulates forkhead box O1 (FOXO1) in CD8 T cells, enabling them to acquire a resident character by upregulating CXCR6, leading to steatohepatitis (MASH), fibrosis, and facilitating HCC development [88].