Genetic changes in the cells lining the inside of the nose might someday help doctors diagnose lung cancer, a recent study suggests.
"The idea that you don't have to sample the disease tissue but can diagnose presence of disease using relatively accessible cells that are far from the tumor . . . is a paradigm that can impact many cancers," Dr. Avrum Spira from Boston University School of Medicine, a member of the study team, told Reuters Health by email.
The layer of cells that covers the surfaces of the body and lines the cavities is known as the epithelium. Researchers found that distinctive changes in gene activity in the nasal epithelium of lung cancer patients closely parallel the changes seen in lung epithelium and can distinguish between benign lung disease and cancer.
"I think the most interesting finding was the genomic changes in the nasal epithelium of lung cancer patients mirror so closely those found in the lower airway," Spira said.
The researchers thought the nose would be "a reasonable surrogate for the 'field of injury' in the bronchial airway," he added, but the surprisingly strong concordance between the nose and lower airway gave them the encouragement to develop a nasal biomarker for lung cancer detection.
"Pulmonary nodules represent a growing diagnostic dilemma in the U.S. as we have started to screen for lung cancer," Spira said. "A nasal swab that is highly sensitive for lung cancer in this setting would enable physicians to avoid unnecessary invasive biopsies in nodule patients who are unlikely to have lung cancer."
Past research has found that gene expression profiles from normal bronchial epithelial cells can distinguish smokers and former smokers with lung cancer from individuals with benign lung disease, and that nasal and bronchial epithelium respond similarly to tobacco smoke.
Spira's team sought to determine whether cancer-associated gene expression in the nasal epithelium might be useful for detecting lung cancer in current and former smokers.
They identified 535 genes that had different activity patterns in the nasal epithelium of patients with lung cancer versus those with benign disease.
Cancer-associated gene changes correlated significantly between nasal epithelium and bronchial epithelium samples, and the genes that were more active in nasal epithelium of patients with lung cancer were among the genes whose activity was most increased in bronchial epithelium of patients with cancer.
When researchers compared models doctors might use to determine the likelihood of lung cancer, nasal gene activity was more accurate than clinical risk factors alone for diagnosing lung cancer, according to the Journal of the National Cancer Institute report.
The combination of clinical factors and gene activity score accurately predicted cancer 91 percent of the time, compared to 79 percent for the model based on risk factors. The combined model also had 85 percent accuracy differentiating lung cancer from benign disease, compared to 73 percent.
"One of the big-picture messages for physicians is that molecular tests like this one are emerging as part of precision medicine approaches for early cancer detection," Spira said.