ERBB2 and colorectal carcinoma: More recently, additional negative predictive biomarkers of response to anti-EGFR treatments in mCRC patients, such as HER2 and MET amplifications, PTEN loss, and right-sided primary CRC, have been identified and summarised in the latest guidelines of the National Comprehensive Cancer Network (NCCN) [155,156,157,158,159,160].