Illustration: PEP MONTSERRAT
Sounding the alarm on a silent killer
And City of Hope’s Li Zhong, Ph.D., is on the hunt.
Zhong, an assistant research scientist in the Department of Clinical and Molecular Pharmacology, is developing an investigational test that may detect lung cancer early by looking for certain antibodies in a patient’s blood. The sensitive test might provide the first tool to detect non-small cell lung cancer tumors when they are still small and offer the best chance at cure.
photo: Paula MyersFrom left, Li Zhong performs lung cancer research with his partners Jingwei Lou and Dave Thu.
Non-small cell lung cancer accounts for 80 percent of all lung cancers. Because the cancer usually causes no symptoms while it develops, most patients already are in advanced stages of the disease by the time physicians spot the tumors on computed tomography or X-ray images. Unfortunately, only 5 to 7 percent of advanced-stage patients survive beyond five years, Zhong said.
While at a previous research position at the University of Kentucky at Lexington, Zhong began experiments to determine whether autoantibodies — antibodies people make to fight their own tumor cells — could be detected in blood samples of lung cancer patients. Antibodies are proteins made by the immune system to fight unwanted invaders in the body — such as bacteria, viruses and even cancer.
“The theory is that our immune system can detect cancer at early stages and responds with the corresponding antibody population,” said Zhong. “These responses happen early — perhaps several years prior to a tumor being detected by traditional imaging.”
The investigators screened blood from patients with non–small cell lung cancers, identifying a constellation of antibodies the body creates in response to those tumors. They did this through molecular techniques that stick tumor-specific proteins, or antigens, on “chips.” When investigators place a blood sample on the chips, the antigens attract any matching, cancerrelated antibodies contained within the blood.
The tests accurately diagnosed early stage tumors in 90 percent of patients who had such tumors, according to the researchers’ study, published in a 2006 issue of the Journal of Thoracic Oncology.
Although the physicians are not yet using the test with patients, Zhong is validating his results at City of Hope using larger numbers of patient samples together with Yun Yen, M.D., Ph.D., director of the Department of Clinical and Molecular Pharmacology, and Kemp Kernstine, M.D., Ph.D., director of the Thoracic/Lung Cancer Program and the Department of Thoracic Surgery.
He also will begin to identify autoantibody signatures of esophageal cancer as part of a National Cancer Institute-funded study focusing on a cancer-cluster city in China where 20 percent of residents die from esophageal cancer.
Interestingly, Zhong began his scientific career testing new strawberry varieties for importation at a strawberry research institute in his native China. Now, 20 years later, his work may lay the groundwork for a day when antigen profiles of several cancers could be placed on a single, compact “chip” that serves as a one-shot test for many tumor types.
If that sounds overly ambitious, consider what Zhong did for the strawberry market: “Now when I go back to China, I see all of these strawberries in markets, strawberries that I originally imported,” he laughed. “They’re disease-resistant, taste better and last longer.”
His next success could bear even more fruit, in the form of millions of healthier people.