Cancer News
OncoLink Cancer News - HealthDay

High False-Negative Rate for HER2 Status Using Oncotype DX

Wednesday, October 12, 2011 (Last Updated: 10/13/2011)

WEDNESDAY, Oct. 12 (HealthDay News) -- Genomic Health's (GHI) Oncotype DX test, a human epidermal growth factor receptor 2 (HER2) assay for breast cancer that uses a method of reverse transcription polymerase chain reaction (RT-PCR), has an unacceptable false-negative rate, according to a study published online Oct. 11 in the Journal of Clinical Oncology.

David J. Dabbs, M.D., from the Magee-Womens Hospital of the University of Pittsburgh Medical Center, and colleagues investigated the concordance rate between the GHI RT-PCR test and immunohistochemistry (IHC)/fluorescent in situ hybridization (FISH) assay of HER2 status. A total of 843 patients with available HER2 GHI RT-PCR assay results were included in the analysis from three participating institutions. All laboratories also conducted FISH analysis to classify their IHC-positive and equivocal cases.

The investigators found that IHC/FISH analysis classified 93 percent of cases as negative, 4 percent as positive, and 3 percent as equivocal. Of the IHC/FISH negative cases, 99 percent were also reported as negative by the GHI RT-PCR assay. All IHC/FISH equivocal cases were negative by the GHI RT-PCR assay. Of the IHC/FISH positive cases, 28, 33, and 39 percent were reported as positive, equivocal, and negative, respectively, by the GHI RT-PCR assay.

"There was an unacceptable false-negative rate for HER2 status with GHI HER2 assay in this independent study. This could create confusion in the decision-making process for targeted treatment and potentially lead to mismanagement of patients with breast cancer if only GHI HER2 information is used," the authors write.

Full Text (subscription or payment may be required)

Specialties Hematology & Oncology
OBGYN & Women's Health

Copyright © 2011 HealthDay. All rights reserved.

I Wish You Knew

Importance of funding cancer research

View More

Blogs and Web Chats

OncoLink Blogs give our readers a chance to react to and comment on key cancer news topics and provides a forum for OncoLink Experts and readers to share opinions and learn from each other.

OncoLink OncoPilot

Facing a new cancer diagnosis or changing the course of your current treatment? Let our cancer nurses help you through!

Learn More