Eriksen AC, et al. - Researchers used a true population-based cohort of patients with stage II colon cancer (CC) in order to assess the prognostic value of programmed death ligand-1 (PD-L1). They assessed PD-L1 expression on tumor cells via immunohistochemistry in 572 colon cancers, and analyzed whole sections from tumor blocks representing the deepest invasive front of the primary tumor. They dichotomized the data by using a cut-off of 5% positivity, and Cox proportional hazards models were utilized in order to determine the prognostic significance for recurrence-free survival and overall survival. A full 6% of tumors were classified as high PD-L1. Factors associated with high PD-L1 were female sex, high malignancy grade, right side localization, and microsatellite instability. Overall, there was no prognostic impact of PD-L1 expression in tumor cells of stage II CC in the entire population-based cohort or in the group of MSI patients.