RB1 and hepatocellular carcinoma: CDKN2A regulates the p16-CDK4/Cyclin/Rb pathway and is characterized above (Figure 2).[21] The CDKN2A A102P mutation has not been characterized, but it is likely to be inactivating.[45] Overall, CDKN2A mutations has been reported in 8% of HCC.[7] ARID1A encodes the AT-rich interactive domain-containing protein 1A, a member of the SWI/SNF chromatin remodeling complex.