PathVysion gene test gaining ground as standard diagnostic.

2003 JUN 19 - (NewsRx.com & NewsRx.net) -- The National Comprehensive Cancer Network (NCCN) has updated its Practice Guidelines in Oncology to indicate that fluorescence in situ hybridization (FISH), the diagnostic technology used in Abbott's Vysis PathVysion test, may be more accurate than immunohistochemistry (IHC), the most commonly used test method for determining HER2 status in women with metastatic breast cancer.

The NCCN is a not for profit, tax-exempt corporation that is an alliance of the world's leading cancer centers. The organization's Clinical Practice Guidelines in Oncology are widely recognized and used as the standard for clinical policy in cancer care, and are the only comprehensive set of guidelines updated annually by any national organization in any area of medicine.

"The new guidelines on HER2 testing will help ensure that physicians and patients have the most accurate information when deciding on the best course of treatment for this life-threatening disease," said Steven Seelig, MD, PhD, divisional vice president, Vysis research and development, Abbott Laboratories. "As a highly accurate test for HER2 diagnosis, PathVysion is a vital tool in the fight against breast cancer."

PathVysion, designed to detect amplification of the HER2 gene in breast cancer tissue specimens, is used to identify which women are potential candidates for Herceptin, a unique monoclonal therapy that specifically targets tumour cells that over express the HER2 protein.

It is the only FISH- based test the U.S. Food and Drug Administration (FDA) has approved for inclusion in the Herceptin package insert for the selection of patients who may respond to treatment. In addition to Herceptin therapy selection, PathVysion is also used for assessing patient prognosis and response to Adriamycin-based therapies, making it the only HER2 assessment method approved for these three claims.

In 25 to 30% of breast cancer patients, the presence of multiple copies of the HER2 gene on a single chromosome, called "gene amplification," leads to over expression of HER2 protein, which plays a pivotal role in the rapid growth of tumour cells. Determination of HER2 gene status is critical for selecting therapeutic options.

HER2 status indicates the likelihood of response to certain chemotherapeutic agents, aids in assessing patient prognosis, and identifies patients who may respond to Herceptin. FISH testing measures the number of copies of the HER2 gene at the DNA level. Using fluorescent coloring and a microscope, physicians can count the actual number of HER2 genes present in the cell nucleus. In comparison, ...