Relationship Between ABO Blood Group and the Risk of Colorectal Cancer: A Retrospective Multicenter Study.

Background: Colorectal cancer (CRC) is the fourth deadliest cancer, with approximately 900,000 deaths annually. CRC is a multifactorial disease in which a set of factors, including environmental, hereditary, and genetic factors, are integrated into cancer development. Studies have suggested an association between hereditary antigens in the human blood group system and the risk of different cancers.