Glycan Microarray Assay Used to Diagnose Breast Cancer

The antibodies in the serum are directed against a dietary specific sialic acid (Neu5Gc)-containing sugar chain which differs from the human sialic acid N-acetylneuraminic acid (Neu5Ac).

Scientists at the University of California San Diego, (La Jolla, CA, USA), used a novel sialoglycan microarray presenting multiple Neu5Gc-glycans and control Neu5Ac-glycans to distinguish the sera of patients with or without carcinoma. They tested the sera from 175 breast cancer patients and other types including 39 prostate, 29 ovarian, 14 lung, 22 colon, 16 pancreatic and 11 endometrium carcinomas, as well as 80 controls matched for gender, and where possible, for age. Sera were tested on glycan microarray slides and analyzed while blinded to the case/control status of the samples.

The antigen detected for breast cancer in the study arises from dietary Neu5Gc incorporation into the cancer marker sialyltransferase (Sialyl-Tn). It is the first example of a biomarker in the form of human xeno-autoantibodies to a dietary molecule. The team discovered that anti-Neu5Gc antibodies could be significant in predicting cancer risk, for diagnosing cancer cases early and in high concentration used as a treatment for suppressing tumor growth. The scientists also found that introducing purified human anti-Neu5Gc antibodies might have immunotherapeutic potential as they specifically kill Neu5Gc-expressing mouse or human tumors when applied at higher concentrations. Sialix Inc. (Vista, CA, USA) whose scientists participated in the study, maintains the exclusive rights to the commercialization of the biomarker and therapeutic applications of the study.

Richard Schwab, MD, who co-led the overall research study, said, "It is likely a combination of signaling immune cells to kill cancer cells and antibodies directly killing cells by recruiting other proteins in the body. Understanding how lower levels of antibodies stimulate cancer growth while strong responses can kill cancer cells will be critical to moving this approach safely into cancer treatment." The study was published on May 1, 2011, in the journal Cancer Research.

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University of California San Diego
Sialix Inc.