ARID1B and intrahepatic cholangiocarcinoma: The Cancer Genome Atlas performed a comprehensive genomic analysis of liver fluke‐negative and hepatitis‐negative ICC, and reported the presence of inactivating mutations in tumour suppressor genes ARID1A, ARID1B, TP53 and PTEN, and functional mutations in oncogenes IDH1/2, BRAF and KRAS.45