It is interesting that mutually exclusive patterns of gene mutations are recognized between TP53 and CTNNB1, or between ARID1A and ARID2. 43 Whole genome analysis by Fujimoto et al46 identified the HCC mutational landscape that can be subclassified into six mutational clusters: cluster 1: ARID2‐PBRM1 (4.9%); cluster 2: ARID1A‐RB1‐APOB‐LRP1B‐PTPRD (47.2%); cluster 3: MACROD2 (4.2%); cluster 4: CTNNB1 (17.1%); cluster 5: CDKN2A (5.2%); and cluster 6: TP53 (21.3%). The gene discussed is ARID1A; the disease is hepatocellular carcinoma.