In the 17 acinar cell carcinomas, 4 tumors harbored somatic mutations in SMAD4; 3 in JAK1, RB1, and TP53; 2 in APC, ARID1A, GNAS, MLL3, PTEN, FAT4, and CTNNB1; and 1 in BRAF, ATM, BAP1, BRCA2, PALB2, RNF43, FAT2, TSC2, and MSH2. Some of the protein products of these mutated genes are druggable, which may pave the way for the development of specific drugs for acinar cell carcinoma. The gene discussed is ARID1A; the disease is acinar cell carcinoma.