PIK3CA and colorectal cancer: Colorectal cancer risk is attributable to rare germline and or somatic mutations in a variety of tumor suppressor genes, that include APC [3, 4], TP53 [5]; proto-oncogenes, KRAS, BRAF, CTNNB1/beta-catenin, PIK3CA, SRC [4]; cell cycle regulatory genes FBXW7 [4]; DNA mismatch repair genes MLH1, MSH2, MSH6, PMS2 [6], DNA base excision repair genes OGG1 [7], MUTYH [8]; and many other common, low-penetrant genetic variants, which together may be associated with colorectal cancer development [9].