Representativity of human mammary tumor cell cultures: DNA-cytophotometry as a method for checking tumour cell characteristics.

Short term cultures (3-6 days) of 40 primary human mammary carcinomas were prepared and compared with the original tumours from which they were derived. As a criterion the nuclear DNA Frequency Distribution Pattern (FDP), cytophotometrically measured, was used. Comparisons were made between the FDPs of smears of freshly-cut tumour surfaces and their cultures. Twenty-nine (73%) cultures showed FDPs identical with the smears. Eleven cultures (27%) showed gross shifts in ratios between different peaks or showed a complete loss of one or more peaks in the FDP and were classified as not representative. Our results show that it is necessary to check primary mammary tumour cultures to determine whether or not they are representative of the original tumour. This is especially so if conclusions are to be drawn from the cultures about the original tumour. Analysis of FDPs in the cell islands of the cultures (migration of cells from attached clumps) resulted in a better understanding of the FDPs found in the smears. We showed that cultures of human mammary tumours either can be composed of cell islands with identical FDPs (diploid or aneuploid) or may show heterogeneity between different cell islands within one tumour.

Feline mammary carcinomas as a model for human breast cancer. I. Sensitivity of mammary tumor cells in culture to cytostatic drugs. A preliminary investigation of a predictive test.

Feline mammary carcinomas were found to maintain well in short-term cultures. Principally the same types of nuclear DNA frequency distribution histograms were recognized in feline mammary carcinomas as in human mammary carcinomas. However, the more abnormal histograms are less frequent in feline than in human mammary carcinomas. Feline mammary carcinomas appeared, at least in vitro, most sensitive to Doxorubicin and 5-fluorouracil. Preliminary, thymidine incorporation studies indicate both cytotoxic and cytostatic effects of Doxorubicin and 5-FU. Methotrexate was found to stimulate thymidine incorporation.