Immuno-molecular characterization of colorectal cancer tumors and its clinical implications

We thank Oh, Lee and Lockhart for their well-informed comment. In addition to an accurate summary of our work, it provides a relevant discussion in light of the recent immunotherapy trials in colorectal cancer (CRC). The authors notably cite the work of Le and colleagues who have shown the association between response to Pembrolizumab and the microsatellite-instable (MSI) status of CRC tumors (1). Indeed, the immune contexture of MSI CRC tumors supports PD-1 blockade as a potential immunotherapeutic modality (2). This susceptibility is likely due to the high mutational burden of these tumors, which in turns leads to the expression of many potentially immunogenic peptides. Consistent observations have been reported in lung adenocarcinoma, where mutational burden has been shown to be associated with response to anti-PD1 treatment (3).