The effect of estrone-progesterone treatment on cell proliferation kinetics of hormone-dependent GR mouse mammary tumors.

Hormone-dependent mammary tumors were induced in virgin GR mice by treatment with estrone and progesterone. Discontinuation of hormonal treatment was followed by regression of the tumor. This response to hormone treatment was also observed in the first transplant generation in inbred syngeneic hosts, but after several transplantations the tumor growth became hormone independent. The hormone dependence of the primary tumors and tumors after a...