Milk proteins and mammary cancer: a review.

Milk proteins are of potential value in characterizing mammary carcinoma from a functional point of view. The major milk proteins are described with special reference to human milk. The caseins, whey proteins and membrane structures in the milk are discussed in terms of their chemical, biological and immunological properties. In vitro culture systems help to define the hormone dependency of normal mammary tissues and mammary carcinomas. The control of proliferation and milk protein production are partially independent, and this becomes especially evident in experimental tumours. Clinical samples of human tumours and plasma from patients with mammary carcinoma show differences in the level of certain milk proteins. These appear to relate to tumour spread, state of differentiation and the presence of hormone receptors.