SynopsisWe review information highlighting the multiple roles of both steroidal (primarily oestrogen) and polypeptide regulators of mammary epithelial cell growth, emphasising the work of our laboratory. Effects of both classes of hormones are complex and involve multiple interactions with non-tumour, host tissue. Oestrogen may induce growth regulatory polypeptide growth factors and interact with them in hormone dependent breast cancer. Progression of hormone-dependent breast cancer to hormone independence may involve multiple genetic mechanisms of oncogene activation, loss of the oestrogen receptor, or loss of hormone responsivity of other gene products. Initial carcinogenesis and progression of mammary epithelium to cancer probably also requires both proliferative stimuli (oestrogen, polypeptide growth factors) and genetic damage, leading to qualitatively different hormonal responses (hormone responsive cancer). Future therapies should be designed to block hormonal stimulation better and to interfere with necessary activated or induced components of malignant progression such as oncogenes or polypeptide growth factors receptor systems.
Cloning of partial cDNA encoding differentiation and tumor-associated mucin glycoproteins expressed by human mammary epithelium.