PIK3CA and neoplasm: In patients with intrahepatic cholangiocarcinoma, TP53 was the most common alteration in ctDNA samples (Figure 4C), whereas TP53, ATM, CCND2, KRAS, BRCA2, mutS homolog 6 (MSH6), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), PTPN11, and UGT1A1 were detected in corresponding tumor tissue (Figure 4D).