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Protein responsible for drug resistance in breast cancer found

By Kieran Ball - 24 May 2011 11:9:0 GMT
Protein responsible for drug resistance in breast cancer found

Scientists at Imperial College London have identified a protein that causes tumours to become resistant to drugs used to treat breast cancer. It is thought that the protein, known as LMTK3, will now become a target for new breast cancer treatments.

Oestrogen is known to be a key promoter of breast cancers, as many tumours have oestrogen receptors on their cell surfaces, which are stimulated by the presence of the hormone. As a result, many treatments will often involve hormone-blocking drugs such as tamoxifen to inhibit the production of oestrogen. However, it has been seen that, over time, these cancers can become resistant to the drugs.

The team of researchers at Imperial managed to isolate a protein known as LMTK3, which appeared to 'enable' oestrogen production in tamoxifen-resistant cancer cells. They noted that breast cancer patients with high levels of the protein had lower survival rates and were less responsive to hormone blocking drugs. Evidence was also found that mutations in the gene responsible for LMTK3 had an impact on the survival rates for women with breast cancer.

The next logical step was to attempt to 'turn off' LMTK3. Using genetic techniques, the scientists were able to block the protein in tamoxifen-resistant cancer tissue in mice. Consequently, the tumours shrank, confirming the team's findings. Professor Justin Stebbin was quoted in the journal Nature Medicine:

''Anti-oestrogen drugs have been very successful at allowing women with breast cancer to live longer, but resistance to these drugs is a common problem. Our results suggest that the action of LMTK3 on the oestrogen receptor has a crucial role in the development of drug resistance.''

''We're now looking for drugs that can block the effects of LMTK3, which we could hopefully give to patients to prevent them from becoming resistant to hormone therapy.''

Clearly, any drugs that can block the effects of LMTK3 will boost the effectiveness of breast cancer therapies.

Unfortunately, the professor believes it will be five to ten years before safe treatments are available for humans.

However, with breast cancer being the one the most common cancers in women, not to mention one of the biggest killers, any new therapies resulting from the research will certainly be welcomed.

Image Credit: © Sven Bahren.