Chromosome anomalies in human breast cancer: Evidence for specific involvement of 1q region in lymphocyte cultures

Constitutional chromosome abnormalities that may predispose a group of individuals to develop certain neoplasms have been reported for some human solid tumors. Deletions of 13q in retinoblastoma, 11p in Wilms' tumor, 1p in neuroblastoma, 3p in renal cell carcinoma, 5q in colorectal carcinoma and 22q in meningioma are examples of such anomalies. In breast carcinoma, a specific cytogenetic defect has not been conclusively identified. We have studied Phytohemagglutinin-stimulated lymphocytes of 76 breast cancer patients, 68 predisposed family members, 40 controls, and 30 additional controls with lung cancer to determine whether nonrandom chromosome defects are present. From each sample 100, G- or Q-banded metaphase spreads were studied for rearrangements. A marked clustering of alterations in the long arm of chromosome no. 1 (q11-22) was seen in breast cancer patients and in some predisposed family members. Alterations in 1q were present in 1% to 3% of metaphases, and included translocations to chromosomes 3, 6, 7, 9,12, 15, 17, 18, 21 and the X; deletion of 1q, or pericentric inversion. Twelve out of 62 (19.3%) familial cases, 3 out of 14 (21.4%) sporadic cases, 9 out of 68 (13.2%) predisposed cases and 2 out of 40 (5%) control cases showed 1q alterations. None of the 30 lung cancer patients showed chromosome 1 anomaly in this region. This is consistent with the reports on primary breast tumor tissues, cell lines and pleural effusions where 1q defects have been reported. We conclude that chromosome 1q rearrangement might be one of the primary lesions specifically associated with the development of breast cancer.