PIK3CA and neoplasm: In tumor DNA, genes with the most recurrent somatic mutations were TP53 (47.14%), PIK3CA (40.00%), and AKT1 (7.14%), while the most frequently mutated genes of ctDNA were TP53 (41.67%), PIK3CA (27.08%), and DNMT3A (8.33%; Fig. 1A, Fig. S3).