Lung cancer is the leading cause of death from cancer globally. Diagnosing lung cancer is a huge problem because the currently available tests are only able to detect it once the tumor has progressed beyond normal limits. That is why a test that determines the presence of cancer at its earliest stage is important because it gives doctors time to treat the cancer.

Researchers from the Boston University School of Medicine say that by observing the patters of "gene expression" of the cells from the airways of the smokers can determine whether the subject is suffering from lung cancer.

Says Dr Avrum Spira, who was the lead researcher of the study along with Dr Jerome Brody, "Our study has identified an airway gene-expression biomarker that will impact the diagnostic evaluation of smokers with suspect lung cancer. Our data also suggests that this method could improve the diagnostic sensitivity of the overall bronchoscopy procedure from 53 to 90 per cent."

Bronchoscopy is a process in which a tube is inserted into the airways of a patient. The researchers believe that this method is 90 percent sensitive in the identification of lung cancer is stage one itself, which will make the treatment of the patient easier.

According to figures, over 3 million people die due to lung cancer annually with over 90 percent of patients contracting the disease due to smoking. In UK alone over 37,100 people were diagnosed with lung cancer in 2003, with just 20 percent of those diagnosed living past the year.