HLA-DRB1 and colorectal carcinoma: Similar to HLA-DRB1, HLA-DRB5 is an MHC class II protein.34 However, unlike HLA-DRB1, HLA-DRB5 is only expressed in a subset of the population.35 This protein is involved in presenting peptides to T-helper cells, aiding in the initiation of an immune response.34 These findings reinforce the importance of immune vigilance/surveillance and its protective effect against CRC development.36 Higher HLA-DRB5 expression may also enhance antigen presentation, resulting in stronger and more specific anti-tumor responses.