If You Think 23AndMe is Just for Personal Curiosity

 Dear Clayton,

Thank you for helping us make discoveries together.

Working with researchers at Dana-Farber Cancer Institute, we found that people carrying a rare inherited genetic variant called EGFR T790M had roughly 25 times higher odds of developing lung cancer. That is equal to or higher than well-established inherited cancer risk variants such as those in the BRCA1 and BRCA2 genes for breast and ovarian cancer.

These findings were recently published in the journal Science, in a peer-reviewed study titled 'Germline EGFR T790M mutation and lung cancer risk.' You can read the paper here.

Many people believe exposure to tobacco smoke is the only risk factor for lung cancer, but tens of thousands of Americans without this risk factor are diagnosed each year. For many people the question of why has had no good answer. This study is a step toward one.

What we discovered together:

•  Researchers identified EGFR T790M as the largest known single genetic risk factor for lung cancer. This could have important implications for genetic testing and future lung cancer screening strategies for people who carry the variant.

•  More common than anyone knew. Among more than 10 million research participants, 641 carried the variant. It remains rare, but that is about ten times more common than public genetic databases had reported.

•  Specific to lung cancer. Often genetic variants that dramatically increase the risk of one cancer also increase the risk of other cancers, but for people with the EGFR T790M variant there were no significant associations with other frequent cancers, such as breast, prostate or colorectal cancer. This finding could help people with this variant know the specific, targeted screening they may need.

•  A window into American history. By combining genetics with ancestry and geography, our researchers traced the variant to British and Irish settlers who migrated to the Southeastern United States. Regional expansion and demographic isolation led to a founder effect, where a small group is genetically separated from a larger population, in the Southern Appalachian region, making the variant far more common among their descendants. Participants with Southern U.S. ancestry were about six times more likely to carry this variant. This is a striking example of how our ancestors' origins can remain relevant to our health generations later.

Data analyzed in the study includes participants in the Lung Cancer Genetics Study, which is funded by the Susan Wojcicki Foundation and powered by the 23andMe Research Institute in collaboration with 22 lung cancer advocacy organizations. To learn more about the study, our collaborators, and eligibility criteria, visit the study landing page.

This kind of research is only possible at scale. By answering our research surveys, you help make discoveries like this possible. On behalf of the 23andMe Research Institute, thank you for being part of this journey.