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.