Scientists may have found a way to determine which smokers are at highest risk of developing lung cancer, by measuring a telltale genetic change inside their windpipes.
Researchers have identified a group of genes that are especially active not only in lung cancer patients but also in those on the verge of developing cancer.
The team believes that a gene test now being developed could help detect these cancers, and find them in the earliest, most treatable, stages.
What's more, the researchers are also working on an experimental treatment that could help to halt the precancerous changes.
For the research, study senior author Dr. Avrum Spira, a critical care physician at Boston Medical Center, and his team collected epithelial cells -- the cells lining the respiratory tract -- from the windpipes of 129 current and former smokers during a bronchoscopy.
A bronchoscopy uses a camera that is snaked down the throat to look for signs of cancer. But in this case, the researchers were looking for cancer-predicting cells higher up in the respiratory tract, in the trachea.
The researchers used so-called "microarray genetic analysis" to measure gene activity in the windpipe cells they collected.
They found a huge amount of gene activity in the PI3K pathway among the smokers diagnosed with lung cancer, compared to those without the disease.
That wasn't altogether a surprise, since PI3K gene has long been suspected as key player in lung cancer. It affects a pathway of other genes. When PI3K-related genes are overactive, too much cell growth can occur, leading to tumours.
But the researchers also found that patients with precancerous lesions in their lungs, called dysplasia, had active PI3K genes in their trachea cells as well, they report in the latest issue of Science Translational Medicine.
This is a key finding since precancerous cells act as a sort of canary in the coal mine, indicating that cancer is about to develop further.
Catching lung cancer early is key, but there is currently no good way to screen for it in early stages. Most people are diagnosed in late stages, when it's too late for treatments to be effective. That's in part why lung cancer is still the leading cancer killer in both men and women in Canada.
The researchers note that it's still not clear whether all lung cancers involve the PI3K pathway, or whether smokers who test negatively for the genes will not develop cancer.
But a company that Spira helped found, called Allegro Diagnostics Inc., is beginning a study of up to 800 current and former smokers. They want to see how well a gene test they created based on the research performs.
Researchers are also working on promising treatments to fight PI3K activation. One compound, called myo-inositol, has already been tested in nine smokers with precancerous lesions. In them, six of the patients saw their lesions improve.
Spira's team went back and checked those study participants' cells and found those who had responded to the compound also saw their PI3K activity drop.
The researchers have patented their findings through the universities.
Myo-inositol supplements are already freely available; it's also found naturally in fruits, beans, grains and nuts.
