Live or let die: oestrogen regulation of survival signalling in endocrine response

Alison J Butt, Robert L Sutherland, Elizabeth A Musgrove

The growth of both normal and neoplastic tissues is determined by a balance between cell proliferation and cell death. Thus, understanding how these processes not only drive tumour growth dynamics but also influence therapeutic responsiveness may aid in the development of more effective cancer treatments. Oestrogen is a major aetiological factor in the development and progression of breast cancer, and its effects in driving breast cancer cell proliferation have been extensively studied. What is less well understood is how oestrogen's role as a survival factor influences breast tumour growth and response to therapy. Recent gene expression profiling studies in breast cancer cohorts have suggested that aberrant apoptotic signalling may play a role in responsiveness to endocrine therapies. Thus, further elucidation of this process may lead to identification of clinically relevant end-points to determine and delineate therapeutic response in breast cancer patients.