Researchers Discover 'Glycan Fingerprint' for Gastric Cancer

Yael Waknine

January 03, 2014

A serum glycan "fingerprint" may eventually serve as a screening tool to identify people with Helicobacter pylori infection at risk for stomach cancer, according to a groundbreaking study published online December 10 in Cancer Prevention Research.

Led by Jay Solnick, MD, PhD, from the Center for Comparative Medicine at the University of California Davis School of Medicine, an international team of researchers found 19 statistically significant differences in serum glycan expression between people diagnosed with gastric cancer and those with asymptomatic nonatrophic gastritis.

"The vast majority of people — 90% — have an asymptomatic relationship with their H pylori. Of the other 10%, 1% to 3% develop stomach cancer and the rest develop ulcers. If our statistical findings turn out to have predictive value, we can identify high-risk patients for treatment and monitoring," Dr. Solnick told Medscape Medical News in an interview.

This is important because very few of the cancer biomarkers currently used in clinical practice actually work, Dr. Solnick added, noting the high prevalence of false-positive results and unnecessary biopsies that occur when indolent conditions are diagnosed while malignancies are missed.

Although the findings are promising and parallel similar "fingerprints" found by the team in a separate study of ovarian cancer, Dr. Solnick cautioned that a prognostic test "is not around the corner."

"It's much, much easier to get statistical significance than predictive value, that's a long way away," Dr. Solnick said.

As previously reported by Medscape Medical News, abnormal patterns of serum glycans — sugars attached to proteins — result from malignant changes in glycosylation processes that allow cancer cells to usurp developmental regulatory control for enhanced proliferation, invasion, angiogenesis, and metastasis. Identifying those patterns could serve as an early biomarker for disease.

Patient Sample Drawn From Mexico

For the study, researchers used acetonitrile at various acidities to isolate sugars from the glycan complexes in serum samples obtained from 72 residents of Mexico City, where there is a very high prevalence of H pylori infection.

Half of the participants had gastric cancer and one quarter had been diagnosed with duodenal ulcers, thought to develop as a different biological response to H pylori infection. The remaining 18 patients with asymptomatic gastritis served as healthy controls.

Running the glycans through mass spectrometry and liquid chromatography analysis revealed patterns for 4 structural groups of affected glycans. High-mannose–type glycans, glycans with 1 complex type antenna, and bigalactosylated biantennary glycans tended to decrease in patients with gastric cancer relative to controls, while levels of nongalactosylated biantennary glycans increased.

Altered serum glycan levels were also observed in the patients with ulcers, with the differences generally pointing in the same direction as gastric cancer, the authors reported.

UC Davis collaborated with the Instituto Mexicano del Seguro Social and Chungnam National University. The study was funded by the National Institutes of Health and the Converging Research Center Program through the Korean Ministry of Education, Science and Technology. Dr. Solnick has disclosed no relevant financial relationships.

Cancer Prevent Res. Published online December 10, 2013. Abstract

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