DNA methylation may influence the effects of aspirin in patients with breast cancer

By Angela Betsaida B. Laguipo, BSNAug 13 2019

Women with a particular DNA feature may live longer if they take aspirin even before they are diagnosed with breast cancer, a new study found.

A team of researchers at the University of North Carolina hypothesized that epigenetic changes might help shed light on the underlying biologic mechanism that links aspirin use to breast cancer outcomes.

Published in the journal, Cancer, the study could help create new preventive measures against breast cancer, like taking aspirin to prevent or treat breast cancer in some people.  

Until today, it’s still uncertain why some people with breast cancer respond to a specific therapy while others don’t. An unending question in clinical and population health research is about the human response to treatments, and why it varies in this study, which was acquired from collective findings from the Long Island Breast Cancer Study Project.

In some instances, gene sequences may play a pivotal role, but in some cases, DNA chemical modifications or epigenetic changes may be valuable, including a process called DNA methylation.

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Aspirin use and breast cancer prognosis

DNA methylation may influence how aspirin affects patients with breast cancer. To arive at their findings, they studied DNA methylation in breast tumor tissues, which include those at DNA sites that govern the 13 breast cancer-related genes expression. This is the first study to explore the effects of aspirin use and prognosis among women with breast cancer.

“The current study suggests that the LINE‐1 global methylation and promoter methylation of BRCA1 and PR in the tumor may interact with aspirin use to influence mortality after breast cancer,” the researchers noted in the study.

The team studied a total of 1,266 women who had breast cancer between 1996 and 1997. They found that about 476 died from any cause, while 202 had died due to breast cancer until 2014. However, the women who consumed aspirin, the risk of dying from any cause and dying from breast cancer was significantly lower among those whose DNA was not methylated in the region controlling the expression of the breast cancer gene – BRCA1 gene.

The findings of the study can shed light on how to identify people who may respond to aspirin therapy after being diagnosed with breast cancer because of their DNA methylation profile. They suggest that further researches should be conducted to provide a more inclusive and comprehensive DNA methylation profile.

"Consideration of DNA methylation profiles as potential modifiers of the aspirin-mortality association may provide new insights on the underlying biological mechanisms on aspirin use about mortality after a breast cancer diagnosis,” said Dr. Tengteng Wang, study co-author, said explained.

“Our findings, if confirmed, may also impact clinical decision-making by identifying a subgroup of patients, using epigenetic markers, for whom pre-diagnosis aspirin use impacts subsequent mortality, and may help refine risk reduction strategies to improve survival among women with breast cancer," added Dr. Marilie Gammon from the University of North Carolina at Chapel Hill.

The study also supports the value of studies looking at interactions between epigenetics and low-cost therapies like aspirin use, which could help predict breast cancer outcomes.

“The study by Wang et al. shows that beyond gene-environment interactions, epigenetic and environment interactions also exist, and suggest that DNA methylation could in the future help to support the identification of individuals for whom treatment may or may not be successful,” Dr. Kristen Malecki of the University of Wisconsin-Madison, said in a statement.

Breast cancer by the numbers

Breast cancer is the second most common cancer among women across the globe. About 12 percent of all new cancer cases and 25 percent of all cancers in women are breast cancer in 2012. Breast cancer is also the most frequently diagnosed cancer of women worldwide.

Breast cancer survival rates vary in many countries. For instance, breast cancer survival rate is 80 percent or over in Sweden, North America, and Japan, while it’s 60 percent in middle-income countries. In low-income countries, the survival rate of breast cancer is below 40 percent.