Hope of Lung Cancer Therapy Boost

[Christine]

http://news.bbc.co.uk/1/hi/health/6160245.stm

It may be possible to save more lives by reversing drug resistance in lung cancer patients, scientists say.

Most lung cancer deaths are the result of the tumour adapting to block the effects of chemotherapy drugs.

Scientists have now pinpointed the chemistry which one type of the disease - small cell lung cancer - uses to achieve this effect.

The Cancer Research UK study, which appeared in the EMBO Journal, raises hopes of sabotaging this process.

The researchers have identified a number of key proteins, which they believe might play a key role in the development of resistance, not only of small cell lung cancer, but other forms of cancer too.

The majority of small cell lung cancer patients can only be treated with chemotherapy because most are undetected until the disease is at an advanced stage when it is too late for surgery.

Tumours with a protein called FGF-2 are known to be less likely to respond to treatment.

The latest study proves that this is because the protein plays an active role in the development of drug resistance.

Second Target

However, the researchers also pinpointed the key role of a second protein, called S6K2.

They found higher levels of this protein in drug-resistant cancer samples.

They also found that patients who had relapsed after treatment had higher levels of S6K2 in their tumours.

Researcher Dr Julian Downward said: "This suggested that chemotherapy initially killed lots of cancer cells, but cells with S6K2 were able to survive and pass on their resistance.

"New cancer cells therefore also had increased levels of S6K2 and the tumour became increasingly resistant to treatment."

Professor Michael Seckl, who also worked on the study, said drugs were already in development that can block the action of FGF-2.

However, he said there was a risk of side effects because the protein also plays important functions in healthy cells.

He said: "S6K2 has fewer functions in healthy cells, so if we can develop new drugs that stop it working, it may be a better way to reverse drug resistance."

Professor John Toy, Cancer Research UK's medical director, said: "This research increases our understanding of how some lung cancer cells survive chemotherapy.

"If this kind of drug resistance could be overcome, it would be a major step forward in the treatment of lung cancer, which has proved so difficult to beat with existing chemotherapy drugs."