PIK3CA and neoplasm: After bioinformatic analyses using the established mutation caller (see Section 4), 13/61 (21.31%) tumor mutations were found in plasma that were also present in the corresponding tumors; 7 mutations in the TP53 gene (53.84%) and 3 in PIK3CA (23.07%) as the most frequently mutated genes (Figure 2 and Figure S4; Table 2 and Table S3).