This October, for Breast Cancer Awareness Month, we will be sharing some of the latest research on this important topic.
What if the same genetic factors that put you at higher risk for developing cancer could potentially increase the chances you’d survive longer if you do get cancer? This counterintuitive possibility is exactly what researchers discovered in a groundbreaking collaboration between the 23andMe Research Institute and the Dana-Farber Cancer Institute.
Understanding cancer risk and polygenic scores
Like most common diseases, cancer is multifactorial – it’s caused by a combination of genetic factors and non-genetic factors like environmental exposures and lifestyle. Polygenic risk scores are tools that can estimate an individual’s inherited genetic risk of developing many common conditions, such as cancers.
A recent study conducted at the Dana-Farber Cancer Institute investigated whether polygenic risk scores may be associated not just with risk of disease, but with clinical outcomes. The study analyzed nearly 24,000 cancer patients to ask whether having a high polygenic risk score, predicting a high likelihood of cancer, also could tell you anything about the prognosis for a person who does go on to develop cancer.
In collaboration with 23andMe, researchers looked at polygenic risk scores for more than 200 diseases to see if any could also predict the prognosis of six common cancer types: non-small cell lung cancer, colorectal cancer, breast carcinoma, glioma, ovarian cancer, and prostate cancer.
An unexpected finding
Surprisingly, they found that among breast cancer patients, those with high polygenic risk scores for breast cancer actually showed longer average survival times than those with low scores. This finding held up even when accounting for other factors like a patient’s age, treatment, or different kinds of tumors.
Why might this be the case?
Cancer-causing genetic changes come in two types: those you’re born with (germline mutations) that appear in every cell, and those that develop over time in specific tissues (somatic mutations) due to factors like smoking or aging. Polygenic risk scores measure only germline mutations.
The researcher’s results raise the possibility that tumors driven more by germline mutations — and corresponding high polygenic risk scores — may tend to be less aggressive compared to tumors that are more driven by somatic mutations.
What comes next
While these results are statistically robust, they’ll need to be confirmed in other studies before changing how doctors might treat cancer patients. With additional investigation, these findings could eventually help doctors provide more personalized prognoses and potentially identify patients who might benefit from different treatment approaches based on their genetic risk profiles.
