HAP1 and neoplasm: This analysis revealed three distinct tumor groups with respect to APOBEC3 signature mutations: 1) a group that showed similarity to A3A-expressing HAP1-TK-M9 clones, 2) a group that showed similarity to A3B-expressing HAP1-TK-M9 clones, and 3) a group that showed little to no significant APOBEC3 mutation signature (Fig 5).