Each tumor accumulates numerous damaging mutations, therefore, three major groups of associated alterations, including the CTNNB1 cluster (CTNNB1, TERT, KMT2D, ARID2, APOB, NFE2L2), the AXIN1 cluster (AXIN1, ARID1A, RPS6KA3) and the tumour protein p53 (TP53) cluster (TP53, KEAP1, CCND1, TSC2) were identified by exome sequencing of HCC20. The gene discussed is ARID1A; the disease is neoplasm.