Missing Link In Lung Cancer
The loss of a single type of protein molecule may play a critical role in the development of three quarters of the most common kind of lung cancer - according to research published in today's British Journal of Cancer (BJC).
The US authors of the study conclude that finding a way to restore the proteins could lead to the future development of new treatments for the disease called non-small cell lung cancer.
The proteins are called type 2 receptors for Transforming Growth Factor-b (TGF-b) and they play a key role in the function of TGF-b. The members of the TGF-b family control several normal biological mechanisms, including cell growth, 'cell suicide' and the formation of blood vessels, which can go awry in tumours.
When the scientists compared samples of lung tumour tissue and corresponding healthy lung tissue taken from 46 lung cancer patients, they found that the type 2 TGF-b receptors were almost completely missing or were much reduced in 77 per cent of the tumour samples.
To confirm that loss of the receptors plays a role in the development of lung cancer, the team looked at lung cancer cells injected and grown in mice. Cells carrying the TGF-b receptors formed smaller, less aggressive tumours than cells without the receptors.
Lung cancer remains the leading cause of cancer death in the world with more than 1.2 million new cases diagnosed every year. Despite major advances in the understanding and treatment of the disease, it is still one of the most difficult cancers to treat.
Lead scientist, Professor Pran Datta who is based at Vanderbilt University in Nashville, says: "We've established for the first time that these important molecules are either missing or that their action is reduced in three quarters of all cases of lung cancer.
"When we restored the molecules in lung cancer cells in mice they reduced the ability of the cells to grow as tumours.
"The next step will be to find out how the receptor molecules are lost during the development of lung cancer. Finding a way to intervene could lead to the development of new treatments for the disease.".
Professor John Toy, Medical Director of Cancer Research UK, which owns the BJC, says: "This research gives us another important insight into the abnormalities involved in lung cancer. Unravelling events that lead to the loss of normal molecules in cancer is extremely important in finding new ways to control the disease.
"However, it's important to remember that the vast majority of cases of lung cancer are preventable as they are caused by smoking. The best way to reduce risk is to quit.".