Men have a slightly higher risk of developing multiple myeloma than women do. However, in a study conducted by the American Association for Cancer Research, scientists found more women than men with multiple myeloma developed lesions; scientists believe the reason for this is based on genetics. For classification purposes only, researchers have noted men are more likely than women to have hyperdiploidy (a higher chromosome count). Women are more likely to have immunoglobulin, natural antibodies plasma cells produce. Although these differences are significant, researchers are unsure of their relationship to multiple myeloma. In both the number of the new cases of multiple myeloma and in deaths, men slightly outnumber women.