ABO blood group and risk of cutaneous malignant melanoma.

Although, for several decades, the role of ABO blood group antigens has been suspected in the development of cancer, to our knowledge, the association between ABO blood group and the risk of malignant melanoma has not been evaluated yet. We, therefore, examined the relationship between ABO blood group and risk of developing cutaneous malignant melanoma. We retrospectively reviewed 445 patients with a histological diagnosis of malignant melanoma. Blood groups were obtained from medical records. The control group was represented by 38 321 patients. We evaluated the data by investigation with statistical analysis to show a statistically significant increased risk of developing a malignant melanoma in the O Rh-negative group (odds ratio = 1.4). We suggest focus on the melanoma cases belonging to the blood groups O Rh-negative in future studies, because all the clues of this study seem to show a correlation between blood groups and the risk of malignant melanoma among these groups.