ResearchDx/PacificDx to Present High-Resolution HER2 Testing Data at the San Antonio Breast Cancer Symposium

Leading contract diagnostics organization demonstrates the value of DNA-based testing for identifying the HER2-Low genomic subtype in high-risk HER2 equivocal breast cancer

Irvine, CA—December 1, 2016—ResearchDx/PacificDx announced today that it will share findings demonstrating the value of DNA microarray comparative genomic hybridization (array CGH) for HER2 genomic subtyping in breast cancer patients at this year’s San Antonio Breast Cancer Symposium. Using molecular test results from tumors with previously documented positive, negative, and equivocal HER2 status, the abstract accepted for presentation will show how high-resolution DNA-based testing can precisely determine a patient’s HER2 status allowing physicians to make decisions about anti-HER2 therapies based on the HER2 genomic subtype of the tumor.


Using molecular data generated from tumor-targeted DNA extractions in their CAP/CLIA certified laboratory, the ResearchDx/PacificDx team focused on the patient subset with tumors that had been called “equivocal” for HER2 gene status. The HER2 gene is a known driver of breast cancer and definitive documentation of the HER2 status in a patient's tumor is critically important for predicting response to targeted anti-HER2 therapies. High-resolution HER2 testing accurately classified the HER2 status in 100% of the tumors and defined the HER2-Low genomic subtype most often called “equivocal” by standard testing methods. This subcategory is characterized at the protein level by low expression of the HER2 protein and no amplification of the HER2 gene on chromosome 17. Response to Herceptin in HER2-Low patients is being studied by the NSABP-B47 clinical trial (hyperlink to trial

“The equivocal HER2 category has become so accepted in breast cancer, people may not recognize the biological reality that this is not a genomic subtype,” said ResearchDx/PacificDx Chief Medical Officer Dr. Shelly Gunn.  “In the era of precision medicine, we have clinical laboratory tools to precisely characterize HER2 status as Positive, Negative, or Low in any breast cancer. Our findings show that high resolution testing can provide an accurate HER2 genomic subtype for every tumor so no patient has to endure the uncertainty of HER2 equivocal results.”

The abstract, which outlines the high resolution testing used to identify the genomic subtype of breast tumors, will be presented by Dr. Gunn as follows:

Title: A clinically validated DNA microarray for high-resolution HER2 testing defines a new genomic subtype in high- risk breast cancer with equivocal results by IHC and FISH

Abstract Number: P1-09-18

Date & Time: Wednesday, December 7th from 5:00 p.m. to 7:00 p.m.

The San Antonio Breast Cancer Symposium will take place December 6-10, 2016 in San Antonio, Texas.

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