PIK3CA and colorectal carcinoma: To summarise, genetic alterations in the following genes seem to predict non-response; alterations in or directly influencing the WNT pathway, alterations directly influencing chromatin remodelling, alterations in EGFR, components of EGFR or other receptor tyrosine kinases or alterations in PIK3CA. These mutations possibly bypass the MAPK pathway in BRAFV600E mutant CRC.