Familial aggregation of nonhematological malignancies in relatives of patients with hematological neoplasms

Familial aggregation of nonhematological malignant disorders (NHMD) was compared in 189 families of patients with hematological neoplasms (HN) with a control group of 36 families of patients with benign hematological disorders and a second group of 33 families of patients with diabetes mellitus. A self-administered questionnaire was used requesting from each family a full list of first- and second-degree relatives, their vital status, current age or age at death, and a list of their chronic diseases, including all malignant disorders. There was no evidence of a significantly increased tendency for developing NHMD among relatives of patients with HN as compared to controls (adjusted odds ratio of 0.88; 95% confidence interval 0.61-1.27). Moreover, in the HN group, no significant difference in the frequency of NHMD was found between the families with and without familial aggregation of HN. Based on the present analysis and our previous observations on familial aggregation of HN, we conclude that the increased aggregation of malignant disorders among relatives of patients with HN is unique to the hematopoietic system and might result from a genetic predisposition to HN in these families.