Collagen gel culture of rat mammary tumor cells as an assay system for determination of therapeutic efficacy of chemotherapeutic agents.

Collagen gel culture of rat mammary epithelial cells was used as an in vitro assay system for determination of the therapeutic efficacy of three cytotoxic agents commonly used in the treatment of human breast cancer, namely 5-fluorouracil (5-FU), methotrexate, and Adriamyin (ADR). The same three drugs were also evaluated in vivo, and a good correlation was obtained between the results in these two systems. A 9-d culture was shown to be more reliable than a 12-d culture, because nondrug-related cell mortality became a confounding factor after 12 d. Although further experiments are necessary, it is suggested that collagen gel culture may well prove to be a useful assay system for determination of sensitivity of tumor cells to cytotoxic drugs with possible clinical applications in the choice of treatment modality administered to cancer patients.