ABO blood group and risk of renal cell cancer

Background: The genetic determinants of sporadic renal cell cancer (RCC) are largely unknown. Previous studies have suggested associations between ABO blood group and risk of various cancers. However, its relationship to RCC remains unclear and no prospective data are available. Methods: We prospectively followed up 77,242 women in the Nurses’ Health Study and 30,071 men in the Health Professionals Follow-Up Study from 1996 to 2008. The information on the ABO blood group was collected from participants’ self-reports in 1996. Incidence of pathology-confirmed RCC was compared using hazard ratios (HRs) and 95% confidence intervals (CIs) derived from Cox proportional hazards models. Results: During 12 years of follow-up, 163 cases of incident RCC were documented in women and 88 cases in men. The multivariate HRs between non-O blood group (combined group of A, AB, and B) vs. blood group O were 1.51 (95% CI 1.09–2.09) in women, 1.08 (95% CI 0.70–1.66) in men, and 1.32 (95% CI 0.95–1.82) in the pooled cohorts. The associations between ABO blood group and RCC were consistent across strata of known risk factors for RCC including age, obesity, smoking, and history of hypertension (Pinteraction ≥ 0.32). Conclusions: We found a suggestive non-significant association between non-O blood group and increased risk of RCC in the pooled cohorts of men and women, and this association was significant in women. Our findings need to be replicated by other prospective studies.