Cell culture media of the 28 CRC cell lines (BRAF-mut = 12; KRAS-mut = 9; PI3K-mut = 13; PTEN-loss = 12, Table 1 and Supplementary Table 1) were analyzed by ELISA assay under standardized culture conditions (see Methods) (Fig. 1a). Here, KRAS is linked to colorectal carcinoma.