Widely lauded for its anti-inflammatory effects, aspirin is often resorted to in regular doses for disease prevention. For example, previous research studies have supported the idea that women who regularly take aspirin and then are diagnosed with breast cancer may live longer, which has perpetuated this as a medical recommendation. However, the latest study out of the University of North Carolina’s Gillings School of Global Public Health shed light on a subgroup of breast cancer patients for whom regular use of aspirin may affect their epigenetics, potentially increasing mortality risks.
DNA Methylation to Control Gene Expression
This study’s key focus was actually on DNA methylation, which is one type of epigenetic change that can affect how DNA is expressed in individuals. In DNA methylation, the addition of methyl groups to the DNA molecule can act to turn genetic activity on or off by effectively altering how “accessible” DNA is to the machinery in the cells that leads to RNA and ultimately protein production. Whereas changes to the DNA sequence itself are permanent and are passed along in a permanent way to offspring if these changes are present in germline cells, epigenetic changes like DNA methylation occur on a different timescale. These can be temporary changes that effectively get turned on or off in a person’s lifetime, and in some cases (and cells) can get passed on to subsequent generations.
Varied Responses in Aspirin Users Diagnosed With Breast Cancer
The UNC study looked at DNA methylation in both breast tumor tissue as well as cancer cells circulating in patient blood in 1,266 women with breast cancer. These patients were interviewed and self-reported as consistent users (or not) of regular preventative aspirin, defined as taken at least once a week for six weeks before being diagnosed with breast cancer.
The DNA methylation profiles of the two different cohorts of aspirin users revealed some critical statistics. In breast cancer patients who had a methylated tumor promotor of breast cancer gene 1 (BRCA1), mortality was elevated by 67% in those who also identified as regular aspirin users. While correlation does not imply causation, this statistically significant difference piqued researcher interest toward further investigation.
On the other hand, in breast cancer patients with an unmethylated BRCA1tumor promotor, and further characterized to also show an unmethylated progesterone receptor genes (PR) and hypermethylated lone interspersed elements-1 (LINE-1), breast cancer death risk decreased by anywhere from 22% to 40%.
The differences in mortality rates between the patient subpopulations suggests that there is more to explore in terms of effects aspirin has on the disease, as well as the delicate interplay between habits and lifestyle, methylation characteristics, and gene expression.
One immediate extension of this research is to expand sample sizes in order to shed further light on the way patterns of aspirin use affect patients, as well as to characterize gene panels more widely to gain more detailed information regarding the genetic controls at play in disease emergence, complications, and risk of mortality. And while the researchers are not making any claims regarding the effects of aspirin on breast cancer incidence, they encourage all patients to consult with their doctors before electing to start or stop taking any of their prescriptions.
Wang, Tengteng, et al. “Prediagnosis Aspirin Use, DNA Methylation, and Mortality after Breast Cancer: A Population‐Based Study.” Wiley Online Library 12 Aug. 2019
UNC Gillings School of Global Public Health “Aspirin May Help Some Breast Cancer Survivors Live Longer, but Cause the Opposite Effect in Others.” UNC Gillings School of Global Public Health Research News, 12 Aug. 2019,