Frequent genetic alterations in PLCs, both HCC and CC, include those in the TP53 and cell cycle-related genes, such as CCND1 and CDKN2A, and in the chromatin-remodelling genes ARID1A and ARID2. HCC is further characterised by activating mutations in components of the WNT/CTNNB1 pathway, while CC is frequently altered in the EGFR and KRAS genes.84 The gene discussed is CTNNB1; the disease is cholangiocarcinoma.