FDA grants authorization to 23andMe for direct-to-consumer genetic test for cancer risk

(c) 23andMe

23andMe, Inc. has received the first-ever FDA authorization for a direct-to-consumer genetic test for cancer risk. The authorization allows the company to provide customers, without a prescription, information on three genetic variants found on the BRCA1 and BRCA2 genes known to be associated with higher risk for breast, ovarian and prostate cancer.

from Scientific American

23andMe will report on three variants in the BRCA1 and BRCA2 genes associated with a significantly higher risk of breast and ovarian cancer in women, and breast cancer in men. The variants may also be associated with an increased risk for certain other cancers. These variants are most prevalent in those of Ashkenazi (Eastern European) Jewish descent, accounting for more than 90 percent of their risk of heritable breast and ovarian cancer, and have been observed at much lower rates in other ethnicities. About 1 in 40 individuals of Ashkenazi Jewish descent has one of these three variants, or "founder" mutations. Women with one of these variants have a 45-85% chance of developing breast cancer by age 70.

These three variants mentioned above are not the most common BRCA1/BRCA2 mutations in the general population: no more than 0.1 percent of women with non-Ashkenazi ancestry carry the mutations.

As per the FDA, a  negative result does not rule out the possibility that an individual carries other BRCA mutations that increase cancer risk. The agency therefore warned that individuals and their physicians should not use the test results to make decisions about treatments, including prophylactic removal of the breasts or ovaries. That should be based on more extensive testing.

In addition, most cases of breast cancer are not hereditary, from BRCA or other mutations, but “sporadic,” meaning they arise at random or from smoking, obesity, exposure to toxic chemicals, hormone use, and other environmental factors.

from The Scientist

Current clinical guidelines for genetic risk evaluation are based primarily on personal and/or family history of certain cancers. However, a perspective by Mary Claire-King, Ph.D. (who received the Lasker award in 2014 in recognition of her pioneering discovery of the BRCA1 gene) has argued for broader access, citing a study where “50 percent of families found to harbor BRCA1 or BRCA2 mutations had no history of breast or ovarian cancer that would have triggered clinical attention.”

This is the third de novo authorization granted by the FDA to 23andMe. In February 2015, the company was granted authorization by the FDA to market the first direct-to-consumer genetic test for Bloom Syndrome. In April 2017, they received FDA authorization to market the first direct-to-consumer genetic health risk reports.

Indications for Use: The company's Personal Genome Service (PGS) uses qualitative genotyping to detect select clinically relevant variants in genomic DNA isolated from human saliva collected from individuals ≥ 18 years with the Oragene Dx model OGD500.001 for the purpose of reporting and interpreting genetic health risks, including the PGS Genetic Health Risk Report for BRCA1/BRCA2 (Selected Variants). The 23andMe PGS Genetic Health Risk Report for BRCA1/BRCA2 (Selected Variants) is indicated for reporting of the 185delAG and 5382insC variants in the BRCA1 gene and the 6174delT variant in the BRCA2 gene.

The report describes if a woman is at increased risk of developing breast and ovarian cancer, and if a man is at increased risk of developing breast cancer or may be at increased risk of developing prostate cancer.

The FDA’s decision was based on data from 23andMe showing that its test can accurately identify the three genetic variants in saliva samples. The company also submitted studies showing that consumers understood the report it will send to customers on what the results might mean, how to interpret them, and where to find additional information.

As per an article in Stat and Scientific American, the test assesses only three of the more than 1,000 known BRCA1/2 mutations, raising concerns that women who are told they do not have any of those variants will be lulled into believing that, as a result, they do not have an elevated risk for breast and ovarian cancer.

Sources: 1 2 3 4

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