ARID2 and cholangiocarcinoma: reported that mutations of TERT and TP53 are the most frequently detected mutations in LEL-CC, whereas gene alterations typically associated with cholangiocarcinoma, such as IDH1, IDH2, ARID1A, ARID2, and BAP1 mutations, as well as FGFR2 fusions, have not been described in LEL-CC (15).