CD274 and colorectal carcinoma: The aims of this retrospective cohort study were to (i) compare the clinicopathological features of CRC among young and old groups, (ii) compare the mismatch repair (MMR) protein status between these two groups, and (iii) compare expression of certain immunohistochemical stains between the two groups, including p53, beta catenin, BRAF, Ki67, and PD-L1.