KRAS and colorectal carcinoma: For instance, low expression of CDX2 is a predictive marker for chemosensitivity,8 mutations in PTPRT serve as a potential predictive marker for metastatic CRC,7 mutations in BRAF V600E is a prognostic factor for stage II microsatellite stable (MSS) CRC,9 and mutations in KRAS or BRAF are associated with worse outcomes for patients with stage III MSS CRC.10, 11