Ahtiainen M, et al. - Given the significance of CD274 (programmed cell death ligand-1, PD-L1)/PDCD1 (programmed cell death-1, PD-1) pathway as the suppressor of the cytotoxic immune response, researchers ascertained differences in immune microenvironment and expression of checkpoint proteins (CD274/PDCD1) in DNA mismatch repair-proficient, mismatch repair-deficient, and hereditary Lynch syndrome-associated colorectal cancer, and assessed the prognostic value of these factors and their combinations. They analyzed 94 mismatch repair-deficient colorectal cancers, 100 age, sex, and AJCC/UICC stage-matched mismatch repair-proficient colorectal cancers, and 48 Lynch syndrome-associated colorectal cancers. Findings revealed that immune cell score, PDCD1, and CD274 had an independent but moderate influence on immune cells. The immunoprofile parameter combining the above three factors seemed to be a strong independent prognostic factor for disease-specific survival and overall survival and had a suggestive impact on disease-free survival. These findings support the utility of immune cell score analysis together with PDCD1 and CD274 detection to enhance the prognostic evaluation of colorectal cancer patients. Particularly, this study supports the analyses from whole tissue sections for reliable and cell-specific analyses of CD274 expression.