Gene Amplification Test Assesses Patient Candidacy for Trastuzumab Treatment

A new kit predicts whether a breast cancer patient is likely to respond positively to trastuzumab (herceptin) treatment.

Based on technology called chromogenic in situ hybridization (CISH), the test uses a DNA probe for the HER2 gene, which is amplified in 18-30% of breast cancers. HER2 CISH test results are quantifiable--removing the subjectivity inherent in tests based on immunohistochemistry (IHC) interpretation schemes. Currently, all patients who are considered for trastuzumab treatment are tested for HER2 amplification or overexpression. CISH test results are visualized under a standard bright-field microscope, as opposed to fluorescent in-situ hybridization (FISH) tests, which need a fluorescent microscope.

Called the SPOT-Light HER2 CISH kit and produced by Invitrogen (Carlsbad, CA, USA), it has received U.S. Food and Drug Administration (FDA; Rockville, MD, USA) premarket approval (PMA). The kit will be available in the United States in mid-August, 2008.

"The current protocol for assessing HER2 gene status is for labs to initially screen tissue samples with immunohistochemistry to gauge whether there is an overabundance of the HER2 protein, as an indirect measure of gene amplification," said August Sick, vice president and general manager of Invitrogen's cellular analysis business. "In the case of an inconclusive test, the samples are typically sent to an outside lab for confirmation. Because the SPOT-Light HER2 CISH kit doesn't need specialized equipment, any histology lab can now assess amplification of the HER2 gene while simultaneously examining tissue morphology."


Related Links:
Invitrogen
U.S. Food and Drug Administration