Association of type-O blood with neuroendocrine tumors in multiple endocrine neoplasia type 1

Context: The ABO blood type system describes the expression of human blood group antigens found on both erythrocytes and normal tissue throughout the body. We recently reported an association between O blood type and the manifestation of pancreatic neuroendocrine tumors in a cohort of patients with Von Hippel-Lindau syndrome. Objective: The aim of the study was to determine whether there is an association of ABO blood type with the development of neuroendocrine tumors in patients with multiple endocrine neoplasia, type 1 (MEN-1). Design: Aretrospective analysis of 105 patients with MEN-1 was performed. Demographic, clinical, and biochemical data were analyzed by ABO blood type. Fisher's exact test was used to determine association between ABO blood type and manifestation of neuroendocrine tumor. Results: Demographic and clinical characteristics were similar amongst blood type cohorts. We found an association between O blood type and the manifestation of a primary neuroendocrine tumor of the gastrointestinal tract, lung, pancreas, and thymus in patients with MEN-1 (P = 0.01). Sixteen of 17 (94%) metastatic tumors had type-O blood, compared to 32 of 43 (74%) with a benign tumor who had non-O blood type. Conclusions: Our findings suggest an association between O blood type and the manifestation of a primary neuroendocrine tumor in patients with MEN-1. Prospective clinical studies are warranted to see whether patient blood type status may be a useful addition to current screening and surveillance practices.