In a subgroupanalysis of cohort A, higher response rates were observed among patients withhigher HER2 expression (ORR for IHC 3+ versus IHC 2+: 57.5versus 7.7%).118 The NCCN guidelines for CRC recommend testing for HER2amplifications for patients with mCRC unless RAS/BRAF mutationshave already been confirmed as HER2 amplification is rare inthis subgroup of patients.102,105. The gene discussed is BRAF; the disease is colorectal carcinoma.