PIK3CA and cancer: Based on their high fN*_CSS and fN*_CAS values (Supplementary file 3), the most vulnerable cancer genes include the tumor suppressors TP53, PTEN, CDKN2A, FBXW7, APC and PIK3R1, as well as proto-oncogenes IDH1, GNAS, PIK3CA and NFE2L2.