PIK3CA and neoplasm: In the study by Kidess-Sigal et al [50], the authors compared KRAS, BRAF, and PIK3CA status between circulating tumor cells, ctDNA, and tissue samples of 15 mCRC patients using a 4-gene NGS panel, and in the 3 patients with both ctDNA and primary tumor samples available, the calculated concordance rate for KRAS was 66.7% (2/3), with 1 false-positive case.