Diabetes drug may prevent lung cancer due to smoking: US researchers

The present study was initiated by a team of researchers headed by Dr Philip Dennis from the National Cancer Institute, a part of the National Institute of Health.

According to the investigators, metformin switches on an enzyme that blocks mTOR, a protein that helps growth of lung tumors caused due to smoking. Nicotine-derived nitrosamine ketone (NNK) is the main cancer-causing agent in tobacco.

“Although smoking cessation is the most important step for current smokers, over half of lung cancer cases are diagnosed in former smokers, raising the importance of identifying those at highest risk and identifying effective preventive treatments," informed Dr Philip Dennis, lead-author of the study.

Adding to this, Dr Michael Pollak of McGill University in Montreal said, “This important laboratory study, together with prior laboratory and epidemiology research, suggests that metformin may be useful in cancer prevention and treatment.”

Study Details
For the study, scientists conducted laboratory trials of the drug on mice. The rodents were divided in two groups and while the first group was given oral dose of the drug, it was injected in the second group.

They found that mice that had been given oral doses of the metformin drug had 40 to 50 percent fewer tumors and those injected with the drug had 72 percent fewer tumors.

Because of the major use of the drug and because of the promise it shows in preventing lung cancer, the researchers are keen on conducting human trials with smokers.

Past studies have found that the diabetes drug reduces the chances of development of pancreatic and breast cancers in the patients suffering from diabetes.

"This important laboratory study, together with prior laboratory and epidemiology research, suggests that metformin may be useful in cancer prevention and treatment," Dr Michael Pollak, who writes a supportive article on the study, said.

The findings of the present study have been detailed in the September issue of the journal 'Cancer Prevention Research' and Dr Pollak’s article also features in the same issue.

Smoking stats
According to the World Health Organization (WHO), tobacco is one of the key causes of deaths across the world and more than 5 million people, suffering from heart disease, cancer, and lung disorders die due to it, annually.

20 percent of the US adult population is estimated to indulge in smoking, as per the data of the US Centers for Disease Control and Prevention.