Study Finds that Air Pollution Can Lead to Breast Cancer

Researchers at the University of Buffalo in New York have found that a woman’s exposure to air pollution at certain times in her life can leave her more susceptible to premenopausal breast cancer. Specifically, when exposed to increased air pollution levels early in life and when delivering her first child, these women are more prone to breast cancer later in life.

The research team, led by Katharine Dobson, MPH, with the Department of Social and Preventive Medicine, found that DNA methylation is affected by higher levels of air pollution. Methylation determines which genes in cells are active, a process that is necessary for cells to function. This alteration of methylation can increase levels of E-cadherin, a protein that contributes to the adhesion of cells, which helps create a stable cellular environment and healthy tissue.

Using data from the Western New York Exposures and Breast Cancer (WEB) study, researchers examined records of 1170 women recently diagnosed with breast cancer and 2116 women without breast cancer who lived in Erie County and Niagara County in New York from 1996 to 2001. Demographic information from the women involved in the study reported where they were born, where they lived when they had their first menstrual cycle, and where they lived when they had their first child (if they had children). This information was compared against data on air pollution levels at 87 sites in western New York during the relevant time periods.

Dobson noted that higher air pollution levels at birth were associated with decreased E-cadherin promoter methylation. Also, she said that higher air pollution levels at the time of the birth of a woman’s first child coincided with increased p16 methylation. Dobson added that in those who developed breast cancer, premenopausal women were more susceptible to early air pollution exposure than postmenopausal women. However, she said that additional research is required to evaluate how air pollution affects DNA methylation in the development and progression of breast cancer.