Breast Tumor Section showing nonamplified HER-2/neu (<4 signals/nucleus). Cells are stained with DAPI. Probe is detected with flurorescein.
There is perhaps nothing more disturbing to a woman than a diagnosis of breast cancer. Beyond the usual fears associated with this dreaded disease is the uncertainty concerning the prognosis. Breast cancer is one of those cancers that can be very deadly but also from which there can be long term survival. Despite a plethora of indicators-tumor size, lymph node involvement, histologic type, nuclear grade, and DNA content-the ability to predict an outcome for any particular person, especially those who are node-negative, has proven problematic. Roughly 140,000 new breast cancer patients each year are node negative, and for the majority of them (two thirds) the prognosis is favorable. But, figuring out which third of these patients should receive aggressive treatment is the key, and more often than may be necessary, the decision is made to use aggressive therapies to be safe. The availability of a test that can put some numbers on the likelihood of a recurrence may mean that more women at low risk of recurrence will be spared the trauma and debilitating effects of chemo- and radiation therapies.
Oncor Inc., of Gaithersberg, Maryland, has introduced into the clinical arena a new test for amplification of the HER-2/neu locus which can shed a little light on this troubled field. HER-2/neu, also referred to as erbB-2, codes for a 185 kD transmembrane oncoprotein which is amplified and/or over-expressed in some breast cancer patients, a feature generally associated with a poorer prognosis than that for women with unamplified HER-2/neu. While this locus has been studied for a number of years, technical problems associated with the most commonly used methodologies (Southern blotting and immunohistochemical staining) have led to some inconsistencies in the data. According to Mary Lowery, Chief of Cytogenetics and Immunopathology at Centura Health/Penrose Hospital in Colorado Springs, Colorado, fluorescent in situ hybridization (FISH) will provide more reliable results.
Effect of HER-2/neu amplification and tumor size.
Oncor's INFORM HER-2/neu
Gene Detection System is a FISH probe assay that can be performed on formalin-fixed, paraffin-embedded breast tissue, the kind of sample which is routinely taken from every woman undergoing breast cancer surgery. A retrospective study using this assay on 220 breast cancer patients showed that 93% of unamplified patients remained cancer-free after three years, dropping to 85% at ten years, while only 70% of patients with amplified Her-2/neu
survived three years, dropping to 55% at ten years. This means that there was a 30- percentage point difference in survival rates between HER-2/neu
amplified and non-amplified patients. Compared with other prognostic indicators, INFORM has been shown to be a strong predictor of recurrence and disease-related death. For example, when compared to tumor size, often used as an indicator of severity of disease, the amplification state proved to be a better predictor of outcome.
While a HER-2/neu probe has been available from Oncor (and other suppliers) for researchers in this field for a number of years, the FDA approved test came on line in January. The Oncor INFORM HER-2/neu Gene Detection System comes with 13 reagents required to perform the test, including a biotin-labeled probe, reagents for detecting and amplifying the signal, and control slides. Inaddition, Oncor conducts user training to ensure qualified laboratories are certified to use the test. The INFORM HER-2/neu Gene Detection System is intended to be performed by users certified by the Oncor Proficiency Program.
For more information, contact Oncor Inc. at 800-776-6267 or visit the company web site at www.oncorinform.com.