Progression of mammary adenocarcinomas as reflected by nuclear DNA content.

In 18 breast cancer patients the DNA histograms observed in the primary tumor at the date of diagnosis were compared with those found in the corresponding local and distant metastases at autopsy up to more than 12 yr later. All patients, except one, exhibited the same type of DNA histogram in both the primary tumor and its metastases. In one patient the DNA histogram changed from an euploid type in the primary breast carcinoma to an aneuploid type in the metastases. The results are interpreted as indicating that mammary adenocarcinoma in general exhibit a high degree of stability of the nuclear DNA content during the history of the disease. It is suggested that in breast cancer progression of the tumor disease is more likely due to a net increase and/or dissemination of tumor cells exhibiting similar genetic properties and malignancy potential than to a progressive dedifferentiation and increase of malignancy of the tumor cells.