Air pollution, DNA changes, linked to premenopausal breast cancer
Exposure to air pollution can predispose women to premenopausal breast cancer. University at Buffalo researchers found an association between breast cancer and higher areas of air pollution among women exposed early in life and during the time women gave birth to their first child.
How air pollution might lead to breast cancer before menopause
The study is the first to look at timing of changes in DNA that make cells unstable and could explain a link between polluted air and premenopausal breast cancer.
The researchers say being exposed to air pollution at birth increases levels of E-cadherin through a process known as DNA methylation that indicates activity within cells. The protein helps cells stick together, keeping them healthy and providing a stable environment.
Study results found women exposed to air pollution early in life were more likely to have altered DNA in their breast tumors.
The study included data from 1,170 women with recently diagnosed breast cancer and 2,116 healthy women who lived in New York's Erie and Niagara counties between 1996 and 2001.
There was alteration of the P16 gene that is involved in tumor suppression that correlated with women exposed to air pollution at the time of their first childbirth.
Katharine Dobson, MPH, an epidemiology doctoral student and research assistant in UB's Department of Social and Preventive Medicine, said, "The investigation looked for an association between exposure to pollution and alterations to DNA that influence the presence or absence of key proteins. Such genetic changes are thought to be major contributors to cancer development and progression, including at very early stages.”
Data from air pollution monitors were used to correlate with information the women provided about where they were born, time of first menses and where they lived when and if they had their first child.
"For breast cancer cases, menopausal status appeared to modify the association between air pollution exposure and E-cadherin promoter methylation, with premenopausal women more susceptible to these early exposures than postmenopausal women."
The researchers say more studies are needed to confirm the link between air pollution and premenopausal breast cancer. They suggest addressing air pollution levels and contents over time that might be promoting breast cancer in younger women, before menopause.
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