New Markers Predict Breast Cancer Prognosis

A validation study has shown that based on DNA changes in tumors of a breast cancer patient, it may soon be possible to distinguish a good prognosis from a poor prognosis. Patients with a good prognosis may not need chemotherapy or hormonal therapy after their tumors have been removed.

Researchers used two three-gene sets of markers that were able to identify 91% of hormone-receptor-negative and hormone-receptor-positive specimens from breast cancer patients who did not experience recurrence of disease. In patients who were also node-negative, the predictive value was 100%.

The retrospective study involved 308 patients, on whom a minimum of four years of follow-up clinical information was available, with an average follow-up of around nine years. Poor prognosis was clinically defined as development of recurrence, as evidenced by either distant metastasis or death. Good prognosis was defined as the absence of recurrence or death.

Researchers were able to use a proprietary pattern of genomic amplification (PGA) fluorescence in situ hybridization (FISH), due to the small number of markers in each reagent set. The technology is based on a mathematical approach that enabled researchers to examine 25,000 genes with no "preference” for one gene over another to define the best, small combination of genes for a specific testing purpose. The validation study was conducted by Exagen Diagnostics (Albuquerque, NM, USA; www.exagendiagnostics.com), which specializes in rapid identification and development of practical genomic markers for prognostic testing.

"With this approach, we are seeking to define a new standard of care by becoming the first company to offer a prognostic panel of tests that examines the patient's tumor tissue to detect changes in DNA copy number in any patient,” remarked Waneta Tuttle, Ph.D., CEO of Exagen. "This is a more practical method than currently available tests using RNA.”




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