Hormone effects on human mammary cancer in organ cultures.

Specimens of human breast cancers and fibrosarcomas were incubated for 4 to 72 hours as organ cultures. The effect of various concentrations of testosterone, progesterone, and 17-beta-estradiol on cell survival and multiplication was measured as changes in incorporation of H3-TdR into DNA. Both types of tumor reacted to the hormones; both stimulations and inhibitions were recorded. Statistical analysis of data demonstrated possible influence of factors other than hormone treatment. The specificity of hormone sensitivity assays in vitro is questioned.