Milk-like fluid in a mammary adenocarcinoma: biochemical characterization.

The milk-like accumulation in the R3230AC mammary adenocarcinoma that follows treatment with estrogen contains lactose, fatty acids, and proteins with electrophoretic properties similar to those of casein and whey of rat milk. This mammary tumor retains the biochemical capacity of the mammary gland in its lactational response to administration of hormone.