The consensus molecular subtypes of colorectal cancer as a predictive factor for chemotherapies against metastatic colorectal cancer.

736Background: Since treatment options of chemotherapy for metastatic colorectal cancer (mCRC) have been diversified, biomarkers which could predict efficacy of chemotherapies are needed for optimal treatment. In this study, we analyzed the association of the treatment outcomes by several chemotherapies and the consensus molecular subtypes (CMS), which was developed from large-scale comprehensive gene expression analysis of colorectal cancer (Guinney J et al. Nat Med 21:1350-6, 2015). Methods: A total of 193 patients with previously treated mCRC were classified in 4 subtypes, CMS1 to CMS4 by using the microarrays data of primary tumors and the “CMS classifier” package for the R software. Then the association between the subtypes and the treatment outcomes was analyzed retrospectively. Results: The193 cases were classified into 21 CMS1, 53 CMS2, 69 CMS3 and 50 CMS4. The molecular characteristics of each subtype such as mutation status of KRAS and BRAF genes, and DNA methylation status were consistent with ...