Navigation Links
Common Breast Cancer Gene Test May Be Flawed, Study Says
Date:11/5/2011

By Amanda Gardner
HealthDay Reporter

FRIDAY, Nov. 4 (HealthDay News) -- A widely used breast cancer test may not be accurate in identifying a gene that is critical in determining which life-saving treatment a woman should get.

The Oncotype DX, marketed by Genomic Health, results in a number of false-negatives for the HER2 gene, according to a study published Oct. 18 in the Journal of Clinical Oncology.

Women who test positive for the gene typically receive the targeted therapy Herceptin (trastuzumab) along with other medications to reduce their chances of recurrence and death.

"Women could be getting the completely wrong treatment," said study lead author Dr. David J. Dabbs, a professor and chief of pathology at Magee-Womens Hospital of the University of Pittsburgh Medical Center.

But, according to Dr. Lori J. Goldstein, director of the Breast Evaluation Center at Fox Chase Cancer Center in Philadelphia, the Oncotype DX test, which actually measures 21 different genes, was not designed to test for HER2, nor is it intended as a substitute for two other widely used and accepted lab tests.

"None of us would request Oncotype for the sole purpose of getting HER2," she said. "We're usually ordering it for other reasons and, as part of that test, we get HER2."

Oncotype has been shown to be reliable in identifying estrogen receptor-positive and progesterone-positive tumors, she added.

The only two valid assays for HER2 are immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH). Both are approved by the U.S. Food and Drug Administration (FDA).

Genomic's Oncotype employs reverse transcription polymerase chain reaction (RT-PCR) to check for HER2.

HER2 is overactive in 15 percent to 20 percent of breast cancers and usually signals more aggressive disease, according to background information in the study.

To test the accuracy of Oncotype DX in assessing HER2 status, the researchers compared results from all three tests for 843 patients who had had samples tested at three laboratories, one in Pittsburgh and two in Ohio.

When results were negative with IHC and FISH, they were also generally negative with Oncotype.

But all 23 equivocal results as reported by IHC and FISH came out negative with Oncotype, the investigators found.

Only 28 percent of positive IHC and FISH results also came up positive with the Oncotype, while 33 percent came out as equivocal and 39 percent as negative.

"Anyone who has had this test performed needs to make sure that their hormone-receptor analyses were done by other FDA-approved methods and not rely upon this test alone," said Dabbs.

Overall, though, only a small proportion of tumors among the 843 women were HER2-positive, noted Goldstein, which could have biased the results.

And, in a statement provided to HealthDay, Genomic Health disagreed with the findings, proposing that the "conclusions appear to be one-sided" and require additional data.

The discordances between tests are "not uncommon" and because of those discrepancies the company began including RT-PCR measurement of HER2 in Oncotype "with the goal of providing added clarity in cases where HER2 results by IHC and FISH are uncertain or conflicting," according to the statement.

HER2 status "should be assessed in all patients by IHC and/or FISH," the company also stated.

A 2010 study funded by Genomic Health found that RT-PCR results actually did agree with FISH results.

More information

The U.S. National Library of Medicine has more on breast cancer.

SOURCES: David J. Dabbs, M.D., professor and chief, pathology, Magee-Womens Hospital, University of Pittsburgh Medical Center; Lori J. Goldstein, M.D., director, Breast Evaluation Center, Fox Chase Cancer Center, Philadelphia; Oct. 11, 2011, statement, Genomic Health; Oct. 18, 2011, Journal of Clinical Oncology


'/>"/>
Copyright©2010 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Adapting to clogged airways makes common pathogen resist powerful drugs
2. A common cholesterol drug fights cataracts, too
3. U.S. National Guard Connects Nationwide with Desktop Alert's Command and Control Mass Notification Systems and Common Alerting Protocol (CAP)
4. US21, Inc. is Granted a Wholesale Distributor Permit from the Commonwealth of Virginia Board of Pharmacy
5. New therapeutic target for most common solid cancer in childhood?
6. Migraine More Common in Women with MS
7. Contrast-enhanced MRI could play a key role in differentiating between common types of arthritis
8. Six "Common Sense" Points Not Included In The Health Care Discussion? Should They Be?
9. Six "Common Sense" Points Not Included In The Health Care Discussion? Should They Be?
10. Common osteoporosis drugs are associated with a decrease in risk of breast cancer
11. Commonwealth Leverage Group and Helium Interactive Form HIE Go-To-Market Partnership
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Common Breast Cancer Gene Test May Be Flawed, Study Says
(Date:7/21/2017)... ... July 21, 2017 , ... The Visiting ... the C. R. Bard Foundation, Inc. to support the music therapy ... service available through the nonprofit home care agency. Using evidence-based methods, professionally trained ...
(Date:7/21/2017)... ... July 21, 2017 , ... Sharon Kleyne is ... product of her research center at Bio-Logic Aqua Research® Water Life Science®, has ... greatest number of sufferers of blindness. “We think that Nature’s Tears® EyeMist® will ...
(Date:7/21/2017)... , ... July 21, 2017 , ... ... cruciate ligament (ACL) offer patients improved quality of life five years after injury, ... Medicine’s Annual Meeting in Toronto, Ontario, Canada. The study followed patients for ...
(Date:7/20/2017)... ... July 20, 2017 , ... ChenMed , a ... joined JenCare Senior Medical Center as Richmond Chief Medical Officer. Dr. ... Medicine, and Associate Chief Medical Officer of Ambulatory Services for the UVA Health System, ...
(Date:7/20/2017)... ... July 20, 2017 , ... ... in Houston, is pleased to announce their expansion to the Midwest with the ... directors Alysse Hollis and Ronald Bell, and of counsels, John Peck and Robert ...
Breaking Medicine News(10 mins):
(Date:7/21/2017)... -- Did you know that PhRMA member companies invested $65.5 billion ... on brand medicines, generics and the supply chain account for 14 ... half of this (7 percent)? Or that the United ... capital investments in high-growth biopharmaceutical startups? ... The biopharmaceutical industry ...
(Date:7/15/2017)... 15, 2017 Enterin Inc., a Philadelphia ... disease (PD), today announced the completion of a $12.7 million ... Ventures III, as well as the participation of existing investors. ... to have the support of New Ventures III and our ... validation of the potential of our platform technology to transform ...
(Date:7/13/2017)... -- RK Logistics Group, Inc. was awarded California ... Fremont, CA headquarters facility where it provides ... San Jose for hi-tech, pharmaceutical and biomedical ... with its Fremont Innovation District, is excited to strategically partner ... to the hundreds of biotech, pharma and biomed companies throughout ...
Breaking Medicine Technology: