Risk factors for development of esophageal cancer and patients at risk have not been well understood
yet. In this study we evaluated the association of ABO blood groups with incidence and clinicopathologic
features of esophageal squamus cell carcinoma (SCC) in 375 cases treated in the referral cancer institute during
five years period (2001-2006). Overall, the most prevalent blood group both in SCC and the general population
was A. In the SCC group, the frequencies of blood groups B and AB were more than and frequencies of blood
groups A and O were less than control group (P value = 0.027). In comparison of individuals with B antigen
(blood groups B and AB) and without B antigen (blood groups A and O), this difference became more
prominent (P value = 0.004) (Odds ratio=1.45, 95% confidence interval: 1.12-1.86). There was no statistically
significant association between ABO and Rh blood groups with age, gender, site and size of tumor, lymph node
involvement, distant metastasis, degree of differentiation, presence of vascular, lymphatic and perineural
invasion and presence of simultaneous multiple cancers. We found presence of B antigen as a possible risk
factor for esophageal SCC. This association was more pronounced in male patients.