Comparison of DNA distributions in primary human breast cancers and their metastases

Quantitative measurements of nuclear DNA in individual cells were performed on fine-needle aspirates from 22 primary breast tumors and their metastases, found either at operation or as much as 126 months afterwards. The DNA distribution patterns of each tumor differed widely. However, the primary tumor and its metastasis always showed similar distribution patterns, irrespective of location or time of occurrence of the metastasis. These results indicate a monoclonal genesis of breast carcinoma. It is suggested that the primary tumor and its metastases are made up of similar cell populations with comparable proliferative activities, which may be information of great importance for diagnosis and treatment of secondary breast malignancies.