ARID1A and cholangiocarcinoma: There are two types of ARID1A variants, including mutant and wild type (not mutated, the opposite of mutant type), while a mutant one is defined as loss of ARID1A expression or low expression of ARID1A. In Namjan et al.’s study (37), the authors reported that reduction of ARID1A expression and/or somatic mutation was associated with CCA progression.