Flow cytometric DNA analyses of benign breast lesions detected by screening mammography.

There is little information regarding flow cytometric DNA analyses of benign breast lesions. This prospective study consists of mammographic and pathological correlation of DNA flow cytometric analyses of specimen mammography-guided fine-needle aspirates (FNAs) of 189 consecutive benign breast lesions and 114 FNAs of adjacent normal tissue as a control. Clinical follow-up was also performed. Aneuploidy was detected in 14 of 189 (7%) benign lesion specimen mammography-guided FNAs and in only 1 of 114 (0.9%) FNAs of adjacent normal tissue (P = 0.01). Aneuploidy was detected in two (33%) benign intramammary lymph nodes compared with four (12%) benign lesions with atypia, one benign lesion (3%) with hyperplasia, four benign lesions (10%) with adenosis, and three (4%) other benign lesions (P = 0.01). There were no significant associations between DNA content and S-phase percentage and patient age, mammographic appearance, or extent. During a median follow-up of 40 months (range, 6-84 months), 2 of 13 (15%) patients with aneuploid benign lesions developed ipsilateral breast carcinoma compared with 5 of 175 (3%) patients with diploid benign lesions (odds ratio, 6.18; 95% confidence interval, 1.08-35.56). Our data suggest that aneuploidy, which is detected in a variety of benign breast lesions, may be associated with a higher risk of development of breast carcinoma. The combined techniques of specimen mammography-guided fine-needle aspiration and flow cytometry provide a practical translational research method for the study of benign breast disease.