Oral Cancer Test Detects Early Genetic Changes

A study has demonstrated that an oral cancer test can detect cancers as well as clinically occult lesions that are likely to progress to cancer. The study, conducted by researchers at Johns Hopkins University (Baltimore, MD, USA), was published in the July 2001 issue of the Journal of Clinical Cancer Research.

The researchers obtained oral biopsy tissue from 46 cancer patients collected in a prior study of the test, which is called OraTest. At that time, the accuracy of the test was questioned by witnesses who suggested that the test produced false-positives. The current researchers, using more sophisticated lab testing, found otherwise. "In the initial multi-institutional OraTest study, investigators identified cancer in only one-third of the 96 biopsied lesions. Our molecular analysis now definitively shows that three quarters of the lesions identified by OraTest are in fact clonal, or potentially precancerous.”

A loss of heterozygosity (LOH) is an indication of a gene deletion, a precursor of cancer. The Hopkins researchers detected LOH in the biopsied tissue of 76% of the OraTest-stained lesions. Moreover, LOH was detected in 100% of the squamous cell carcinoma, 82% of the carcinoma-in-situ, and 59% of lesions that had appeared normal under the microscope. The blue-staining test's active ingredient is tolonium chloride. The test was developed by Zila, Inc. (Phoenix, AZ, USA). The company has agreed to make detection of these early genetic changes one of the endpoints of its upcoming phase III study involving 600 patients at 40 sites.





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