Relationship Between ABO Blood Group and Microsatellite Instability in Colorectal Cancer: A Retrospective single-center Study

Abstract Background Colorectal cancer (CRC) is the second most common cancer in both women and men. Microsatellite instabil (MSI-H) CRC is a molecular subgroup and has distinct clinical and pathologic features from non-MSI-H CRC. Studies have suggested an association between hereditary antigens in the human blood group system and the risk of developing various cancers but the relationship between blood groups and MSI-H colorectal carcinoma has not been investigated. This study aimed to investigate the relationship between microsatellite instability and ABO blood group in patients with MSI-H colorectal carcinoma. Methods A total of 144 patients operated for non-metastatic colorectal cancer including 72 patients with MSI-H and 72 patients with non-MSI-H colorectal cancer as the control group, were included in the study. Demographic and clinicopathological features, blood groups and microsatellite status were examined among two groups. Microsatellit instability was examined by immunhistochemistery(IHC). Results Among all patients, the median age was 59.65 (range 24–89) and 57.6% were male. MSI-H and non-MSI-H groups were similar in terms of age, gender distribution and comorbidities. Patients with MSI-H CRC had significantly common O-blood-group than non-MSI-H group (44.4% vs 18.1%, p:0.001). Also patients with MSI-H colorectal cancer were found to have significantly more right-sided (73.6% vs 36.1%, p < 0.001), mucinous (30.4% vs 9.7%, p: 0.003), high-grade tumors and earlier stage disease. Conclusions MSI-H colorectal cancers are an important subgroup in colon cancer with different molecular and clinicopathological features. This study is the first to examine blood group distribution in MSI-H colorectal cancers, and it was observed that O-blood group was more common in MSI-H colorectal cancers than in non-MSI-H patients.