Potential and problems with growth of breast cancer in a human tumor cloning system.

A human tumor cloning system has been utilized to culture 431 patients' breast cancer specimens. Overall, 288 or 67% of the specimens formed colonies in soft agar. Of the primary lesions 188/260 (72%) formed colonies and 100/171 (58%) of the metastatic lesions formed colonies. The median number of colonies per 500,000 nucleated cells plated was 47 for the primary lesions and 30 for the metastatic lesions. Growth from a variety of metastatic sites ranged from 22% for intradermal lesions to 77% for solid visceral metastases. Methods to increase the number of colonies from a specimen are reported including increasing the number of nucleated cells plated and making a variety of changes in the growth media. None of these methods has had a major impact on colony growth. The antitumor activity of standard anticancer agents such as adriamycin and medroxyprogesterone in the assay is presented. In addition, in vitro results with two new anthracene derivatives demonstrate good antitumor activity for the derivatives. The cloning assay represents a new model for both the basic and clinical studies of human breast cancer.