In the present review, we summarized the mutations of epigenetic regulators, including ARID1A, SMARCA2, SMARCA4, KDM6A, KMT2C, KMT2D, and BRD4 in GI cancers—in particular, pancreatic cancer—and found these regulators to be frequently mutated. The gene discussed is ARID1A; the disease is pancreatic neoplasm.