ARID1A and cholangiocarcinoma: (16)] have failed to find CCA harboring both ARID1A and KRAS mutations (another frequently mutated gene in CCA), whereas these tumors had lost ARID1A expression suggesting that loss of ARID1A expression might represent an alternative (to ARID1A genomic variations) mechanism for ARID1A-driven carcinogenesis in CCA, and this could also be an alternative to KRAS mutations-driven CCA development.