Nanoarray analysis may help identify gastric cancer

Last Updated: 2015-04-22

By Larry Hand

NEW YORK (Reuters Health) - Analysis of breath samples could become a screening tool for gastric cancer and a surveillance tool for precancerous lesions, according to researchers in Israel and Latvia.

The group's previous research, in patients from China, "already demonstrated the possibility of volatile marker testing in diagnosing gastric cancer," Dr. Hossam Haick, professor of chemical engineering at Technion-Israel Institute of Technology, Haifa, Israel, told Reuters Health by email.

The new study, however, involved substantially more patients, he said. And "most importantly," he added, it shows for the first time that analyzing patterns of volatile organic compounds (VOCs) enables not only detection of cancer, but also precancerous lesions.

Dr. Haick and colleagues used gas chromatography linked to mass spectrometry (GCMS) and cross-reactive nanoarrays combined with pattern recognition to study breath samples of 484 patients at the Riga East University Hospital in Latvia.

Ninety-nine patients had adenocarcinomas; the others had non-malignant diseases, including peptic ulcers. Researchers collected two breath samples from each patient, for two different analyses.

GCMS analysis identified 130 different VOCs in the breath samples. Eight VOCs had distinctive breath prints to identify patients with cancer or at high risk, the researchers reported online April 13 in Gut.

Through nanoarray analysis, the researchers identified collective VOC patterns rather than specific quantities of VOCs. This made it possible for them to discriminate between patients with gastric cancer and others in the control group with 73% sensitivity, 98% specificity, and 92% accuracy.

In the control group, using the "operative link on gastric intestinal metaplasia" (OLGIM) staging system, the researchers stratified patients as grades 0-IV, with grades III-IV being a high risk of cancer. The sensitivity, specificity, and accuracy came to 97%, 84%, and 87%, respectively for gastric cancer versus OLGIM 0-II and to 93%, 80%, and 90% for gastric cancer versus OLGIM III-IV.

"The nanoarray provided excellent discrimination between patients with (gastric cancer) and low-risk OLGIM stages, and, critically, between patients with (gastric cancer) and high-risk OLGIM stages," the researchers wrote.

The biochemical mechanism for VOC emissions linking to cancer and precancerous lesions remains under debate, they wrote.

"This nanotechnology is still at the research phase," Dr. Haick said. He outlined three research priorities for now: prove the technology's capability under different conditions, validate the technology in real-life screening settings, and develop it further for use in point-of-care settings.

"In addition, the potential evaluation of the method for detecting a number of diseases during the same analysis is an attractive approach that will be addressed," he added. "Piloting of a large population-based study has been initiated within a multi-centric study aiming at gastrointestinal cancer prevention (www.gistar.eu)."

The European Commission 7th Framework Program funded this research, and the Latvian Council of Science partially funded the clinical work in Latvia.

SOURCE: http://bmj.co/1aZCjC2

Gut 2015.