Gene Panel Spots Mutations Other Breast Cancer Test Misses

DNA and chromosome

The US Supreme Court ruling that genes can’t be patented is good news for members of families with a history of breast or ovarian cancer.

That’s the opinion of investigators who, freed by the landmark decision, developed a comprehensive genetic panel. They say it can identify mutations in approximately 25% of patients who had normal results on a commercial assay for BRCA1 and BRCA2mutations (BRACAnalysis, Myriad Genetics).

The recent US Supreme Court decision that invalidates gene patenting has really opened the door to apply modern genomic technologies to the screening of breast cancer using cancer panels and next-generation sequencing. We’re now able to test, in a single assay, all known breast cancer genes, and at the same time evaluate all mutation classes — small mutations as well as complex genomic deletions and duplications.

– Tomas Walsh, PhD, Associate Research Professor of Medical Genetics at the University of Washington in Seattle (USA).

Dr. Walsh presented the research here at the American Society of Human Genetics 63rd Annual Meeting. The assay developed by Dr. Walsh and his team, known as BROCA, can detect all single base substitutions, insertions, and deletions, and copy number variants in all 26 genes known to be implicated in breast cancer.

It’s just known genes that are put on a panel. The idea of looking at more than just BRCA1 and BRCA2is an obvious thing to do, but the technology limited it until next-generation sequencing came online. The inclusion of the additional genes in the panel does not mean that they confer a risk equivalent to that of BRCA1 and BRCA2Some of the mutations, such as those in CHEK2, are known to be present in approximately 1% of women without breast cancer and 2% of women with breast cancer. In contrast, BRCA1 is present in roughly 5% of women with breast cancer, but in only about 0.001% of women in the general population. The differential effect, therefore, is far larger than with the other mutations screened for in the panel, Dr. Lawrence Brody, PhD, chief and senior investigator at the Genome Technology Branch, National Human Genome Research Institute, in Bethesda, Maryland (USA) said.

I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

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References: http://www.medscape.com/viewarticle/813242; American Society of Human Genetics (ASHG) 63rd Annual Meeting. Abstract 90. Presented October 24, 2013.

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