CTA: Should commercial direct-to-consumer cancer gene tests include SNPs that are not yet medically actionable?

Dr Roberts: Again, I think this would depend on the test in question. Our work on Alzheimer’s disease (AD) suggests that individuals have many non-medical reasons for wanting genetic risk information, including to inform advance planning decisions such as whether and how much long-term care insurance to purchase. Knowledge of one’s genotype could also let consumers know if they would be eligible for the growing number of prevention trials being conducted with adults at high genetic risk for AD and other disorders.7

CTA: The PGen study found that gene test results can increase consumers’ use of dietary supplements, apparently in the belief that vitamins or other supplements might reduce disease risk.8 Is that a concern?

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Dr Roberts: I think it is somewhat concerning in that people may be wasting their money and/or investing hope in treatments that have not been shown to have any clinical utility. I am less concerned about physical risks to those who use vitamins and dietary supplements, although the supplement industry in the United States has been criticized for a relative lack of regulation and certain supplements are not without risks if taken in excessive amounts.

CTA: PGen did not find that consumers who receive ‘elevated’ cancer risk results from personal genomic tests are more likely to seek cancer screening services. Why might that be the case? 

Dr Roberts: First, the ‘elevated’ risk for most of these tests is not that pronounced, and people are not likely to act upon test results suggesting very modestly increased risk. Second, there are many potential barriers to uptake of cancer screening, including access to care and negative attitudes toward more invasive screening approaches. Finally, recommendations for many screening tests are often based on age, and some consumers may not be in the appropriate age range.


  1. Roberts JS, Gornick MC, Carere DA, Uhlmann WR, Ruffin MT, Green RC. Direct-to-consumer genetic testing: user motivations, decision making, and perceived utility of results. Publ Health Genomics. 2017 Jan 10. doi: 10.1159/000455006 [Epub ahead of print]
  2. Ostergren JE, Gornick MC, Carere DA, et al. How well do customers of direct-to-consumer personal genomic testing services comprehend genetic test results? Findings from the Impact of Personal Genomics Study. Publ Health Genomics. 2015;18(4):216-24. doi: 10.1159/000431250
  3. Meisel SF, Carere DA, Wardle J, et al. Explaining, not just predicting, drives interest in personal genomics. Genome Med. 2015;7(1):74. doi: 10.1186/s13073-015-0188-5
  4. Baptista NM, Christensen KD, Carere DA, Broadley SA, Roberts JS, Green RC. Adopting genetics: motivations and outcomes of personal genomic testing in adult adoptees. Genet Med. 2016;18(9):924-32. doi: 10.1038/gim.2015.192
  5. van der Wouden CH, Carere DA, Maitland-van der Zee AH, et al. Consumer perceptions of interactions with primary care providers after direct-to-consumer personal genomic testing. Ann Intern Med. 2016;164(8):513-22. doi: 10.7326/M15-0995
  6. Carere DA, VanderWeele TJ, Vassy JL, et al. Prescription medication changes following direct-to-consumer personal genomic testing: findings from the Impact of Personal Genomics (PGen) Study. Genet Med. 2016 Sep 22. doi: 10.1038/gim/2016.141 [Epub ahead of print]
  7. Roberts JS, Christensen KD, Green RC. Using Alzheimer’s disease as a model for genetic risk disclosure: implications for personal genomics. Clin Genet. 2011;80(5):407-14. doi: 10.1111/j.1399-0004.2011.01739.x
  8. Gray SW, Gollust SE, Carere DA, et al. Personal genomic testing for cancer risk: results from the Impact of Personal Genomics Study. J Clin Oncol. 2017;35(6):636-44. doi: 10.1200/JCO.2016.67.1503