Scientists have identified a molecular 'flag' in women with breast cancer who do not respond or have become resistant to the hormone drug tamoxifen.
Tamoxifen - used alongside traditional chemotherapy and radiotherapy - blocks the female hormone oestrogen that, in certain breast cancers, is required by the tumour to grow; it has been shown to improve cancer survival rates by up to one third.
However, about one third of patients with the appropriate type of breast cancer - known as oestrogen receptor positive breast cancer - do not respond to tamoxifen or develop resistance to the drug. Oestrogen receptor positive breast cancer is the most common form of the disease accounting for 70% of cases.
Now, a team from the University of Manchester's Paterson Institute for Cancer Research has identified a molecular flag or biomarker that will help doctors predict which patients will respond best to complementary (adjuvant) hormone therapy with tamoxifen.
"The identification of molecular flags to classify subgroups of breast cancer and so determine the best treatment for each patient is of increasing importance in cancer therapy," said study lead Professor G-ran Landberg.
"Tamoxifen has been shown to be highly effective in some breast cancer patients when used alongside traditional cancer therapies but, in a third of cases, the result has not been what we would hope. If we can predict which patients will respond to tamoxifen, and those who won't, then this is clearly advantageous as it means the correct treatment is provided instantly which will improve disease outcomes."