Chromosome Fragility of Lymphocytes from Breast Cancer Patients in Relation to Epidemiologic Data

The chromosomal fragility of peripheral blood lymphocytes from 50 women, undergoing operations for breast tumors (47 carcinomas, 2 intraductal papillomatoses and 1 malignant lymphoma) was studied to ascertain the association between chromosome fragility and epidemiologic data, such as a family or personal history of cancer, hormonal status, etc. Under conditions of folic acid and thymidine depletion, the average number of gaps and breaks on the patients' lymphocyte chromosome was 6.02±5.28 and that in the control medium was 2.0±2.0 while those of healthy controls were 5.8±5.5 and 1.36±1.22. These gaps and breaks were mostly seen in group A chromosomes (4.1±2.6) in 24 patients, including the 2 with benign tumors and the 1 with the lymphoma as well as 11 healthy controls. They were frequent in group B (3.0±0) in 3 patients, in group C (4.3±2.9) in 11 patients, and in groups D (2.0±1.0) and E (3.0±1.0) in 3 patients from each. This different distribution of gaps and breaks correlated neither with the patients' age nor with their tumor's histology, but patients having a late menarche were distributed in non‐A groups. There was low inducibility of breaks in patients with a family history of breast cancer and/or relatively rare cancers. The availability of common fragile sites for studying an individual's susceptibility to cancer is discussed. One patient showed a bromodeoxyuridine‐requiring heritable 10q25 fragile site. Another, with triple primary cancers, showed a constitutional translocation of t(5;19)(q15;q13).