Sputum Test May Help Diagnose Lung Cancer in Patients with Lung Nodules

For immediate release: January 15, 2015

University of Maryland researchers identify biomarkers to distinguish early-stage lung cancers from non-cancerous nodules

A simple sputum test may help to diagnose early stage lung cancer in patients with lung nodules, according to a study led by University of Maryland School of Medicine researchers and published in Clinical Cancer Research, a journal of the American Association for Cancer Research.

The test has the potential to improve lung cancer screening practices by reducing the need for invasive diagnostic procedures. Currently, patients who are at high risk for lung cancer receive a chest CT scan to look for abnormalities in the lungs. However, there is a high-false positive rate for CT scans, and invasive procedures, like biopsy, are often required for a definitive diagnosis.

“With lung cancer screening rates on the rise, there is a critical need for a reliable and noninvasive method for diagnosing the disease,” explains Feng Jiang, MD, PhD, associate professor in the Department of Pathology at the University of Maryland School of Medicine and a researcher at the UM Marlene and Stewart Greenebaum Cancer Center. “Our work may help address this important clinical challenge by identifying biomarkers of lung cancer found in sputum.”

In the study, researchers developed a panel of three microRNA, miR-21, miR-31 and miR-210, which are present in the sputum of patients with lung cancer. They then tested the panel in a group of 122 patients who were found to have a lung nodule through a chest CT scan, 60 of whom were diagnosed with cancer through invasive testing. When compared with these definitive findings, the sputum panel showed a positive test for cancer in 82.93 percent of patients who had cancer and a negative test result in 87.85 percent of the patients who didn’t have cancer. The test was also administered in two independent groups of 136 and 155 patients with a lung nodule, with similar results.

While the findings show that sputum miRNA serve as biomarkers for lung cancer, Dr. Jiang says the panel will need to be expanded before it can be used clinically to provide a definitive cancer diagnosis.

“We need the test to be close to 100 percent accurate in diagnosing and ruling out cancer,” Jiang explains. “We are now applying new technologies to identify additional miRNA sputum biomarkers of lung cancer with the goal of expanding our biomarker panel to generate a test with high efficiency that can be practically used in clinical settings for lung cancer early detection.”

The study builds on earlier research conducted by Dr. Jiang and a University of Maryland research team, which looked at whether genes believed to be tumor-activators occurring in cells were found in sputum.