US scientists have developed a genetic test to predict early stages of lung cancer by looking for genetic changes in the cells of a smoker’s airways.
The results of the study are published online in the journal Nature Medicine.
Dr Avrum Spira from the Pulmonary Center at Boston University, Massachusetts, and fellow researchers took tissue samples from smokers who were tested for lung cancer and compared the genetic structure of those who were given the all clear against those who went on to develop the disease.
Cigarette smoke passes into the lungs via the airways, and creates a “field of injury” as the scientists called it. They had a hunch that this field of injury might give genetic clues for early stage lung cancer.
In effect this is what they found. First, in a preliminary study they identified an 80-gene biomarker that can distinguish smokers with and without lung cancer.
They did this by comparing the genes from large-airway cells taken during bronchoscopy examinations of 77 smokers suspected of having lung cancer and comparing them to a commercially available gene profiler, in this case the Affymetrix HG-U133A microarray. This holds the gene pattern for 14,500 well-characterized human genes and is used by scientists to explore human biology and disease.
The next stage was to test the method’s reliability.
So they tested the biomarker on samples from large-airway cells from another independent 87 patients with suspected lung cancer and found that across all subjects their biomarker method had an overall sensitivity for stage 1 cancer of 90 per cent.
Combining this large-airway biomarker method with a cytological method that examines the cell abnormalities of lower airway cells nearer the lungs also taken at bronchoscopy improved the predictive power of the combined method to 95 per cent.
The scientists concluded that this study has shown that it might be possible to diagnose early stage lung cancer by looking for particular genetic level changes in large-airway cells that might otherwise appear to be normal.
Lung cancer is the leading cause of death from cancer in the US and the rest of the world. It has a high rate of mortality with between 80 and 85 per cent of patients dying within 5 years.
The high death rate is partly due to the lack of effective tools to diagnose the cancer in its early stages. This study is a step toward developing an effective early diagnostic tool for lung cancer.
“Airway epithelial gene expression in the diagnostic evaluation of smokers with suspect lung cancer.”
Avrum Spira, Jennifer E Beane, Vishal Shah, Katrina Steiling, Gang Liu, Frank Schembri, Sean Gilman, Yves-Martine Dumas, Paul Calner, Paola Sebastiani, Sriram Sridhar, John Beamis, Carla Lamb, Timothy Anderson, Norman Gerry, Joseph Keane, Marc E Lenburg and Jerome S Brody.
Nature Medicine, Published online: 04 March 2007
doi:10.1038/nm1556.
Written by: Catharine Paddock
Writer: Medical News Today