KRAS and colorectal carcinoma: The importance of tumor mutational profile was uncovered by the PRIME trial (NCT00364013), retrospective subgroup analysis of data from CRYSTAL trial (NCT00154102), and the phase II OPUS trial (NCT00125034).21-23 Pooled analysis of the CRYSTAL and OPUS trials further confirmed benefit of cetuximab plus chemotherapy in the first-line for KRAS wild-type mCRC vs no benefit in KRAS-mutated CRC.24 These trials established KRAS mutational status as a predictive biomarker.