Microarray Diagnoses Lung Cancer

Using microarray technology and T7 phage display libraries, the scientists tested more than 4,000 proteins by comparing samples from healthy people and patients with NSCLC. Eventually, they identified seven proteins that were significantly different between patient and healthy groups. They then selected the five most predictive and combined them on a single diagnostic chip.

When tested against a separate group of healthy participants and cancer patients, the five markers combined showed a diagnostic accuracy of 89.9%, which is greater than even the best of single marker tests. The false-positive rate was only 5%. To make the test easier, the research team used samples from patients with advanced NSCLC who should be more likely to express a wider variety and higher levels of antibodies, and from healthy subjects who were at high risk for lung cancer.

"Much emphasis has been placed on the discovery and characterization of unique tumor markers,” noted Li Zhong, Ph.D., of the University of Kentucky's Chandler Medical Center (Lexington, USA). However, to date, nobody has been able to show that a single biomarker can be used reliably to diagnose the disease in its early stages, when it is most easily cured, he observed.

The team wants to extend the research to include patients with early-stage disease and matched-control subjects. They say it is possible that the five markers they found could be replaced or extended by others. The work of Dr. Zhong and his colleagues was reported in the November 15, 2005, issue of the American Journal of Respiratory and Critical Care Medicine.




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