ABO Blood Groups and Cancer

Summary

Problems noted in the methods used to study differences in the distribution of ABO blood groups in persons with various malignant diseases were examined. Attention to these problems might result in more consistent confirmation of such work. Diagnostically confirmed cases of cancer of the breast, cervix, pancreas, colon, stomach, and leukemia were obtained from the Charity Hospital of Louisiana Tumor Registry, and their ABO blood group distribution was compared to a sample 5000 individuals who voluntarily donated blood to the same hospital. For the comparison group, there were no differences in ABO distribution between the sexes, whereas blacks had a greater frequency of type B and a lesser frequency of type A than whites. No excess risk for cancer of the breast, cervix, or colon was associated with blood group A. A relationship between blood group A and cancer of the stomach was found among blacks as well as whites. Previous reports of blood group A associated with cancer of the pancreas were also supported. An increased risk of leukemia with blood group A was found among black males and white females, but its interpretation is open to question.