Out of the 20 most commonly mutated genes in CCA reported in the literature [18], only six genes were altered in biliary ITPN: TP53 at a very low frequency, BRAF (non-V600E), and chromatin remodeling genes (ARID1A, ARID2, KTM2C, and BAP1). The gene discussed is ARID1A; the disease is cholangiocarcinoma.