Recent advances in cancer exome sequencing have led to the identification of AT-rich interactive domain-containing protein 1A (Arid1a), a key member of the switch/sucrose nonfermentable (SWI/SNF) chromatin-remodeling complex, as one of the genes that is most frequently mutated in human HCC, present in approximately 10–15% of the patients [31,43]. The gene discussed is ARID1A; the disease is cancer.