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Air pollution strongly affecting women is known to raise the threat of experiencing cardiovascular events. It now appears that the exposure to air pollution at certain life stages is involved in premenopausal breast cancer. A recent study undertaken by the University at Buffalo asserts that air pollution exposure early in life and when a woman gives birth to her first child alters her DNA and paves way for premenopausal breast cancer later on.

Higher air pollution exposure at birth supposedly modifies DNA methylation, which can elevate levels of E-cadherin. The protein E-cadherin, vital for the adhesion of cells seems to play an important role in maintaining a stable cellular environment and also healthy tissues. Methylation may be a chemical process that aids in detecting which genes in a cell are active, a process essential to normal cellular function. During the study, women suffering from breast cancer who lived in a region with more air pollution allegedly had higher chances of having a change in the DNA of their tumor than those who lived in a less-polluted region.

“To our knowledge, this is the first study to examine exposure to ambient air pollution at key points in a woman’s lifetime. 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,” added lead investigator Katharine Dobson, MPH, an epidemiology doctoral student and research assistant in UB’s Department of Social and Preventive Medicine.

This investigation is based on data from the Western New York Exposures and Breast Cancer (WEB) study that gathered information from 1,170 women recently diagnosed breast cancer and 2,116 healthy women who lived in New York’s Erie and Niagara counties between 1996 and 2001. Study subjects provided information on where they were born, where they lived at the time of their first menstrual period, and, if they had children, where they lived when they bore their first child. All data from air monitors operating in the relevant time periods was put to use for ascertaining the amount of particulate matter at each participant’s residence at those time periods.

Information about air pollution levels was attained from 87 sites in Western New York that matched with residence location at year of birth, year of menarche and year of first child birth. It was noted that reduced E-cadherin promoter methylation can be seemingly linked with higher exposure at birth, and increased p16 methylation with higher exposure at the time of a first child birth. In breast cancer cases, menopausal status possibly changes the relation between air pollution exposure and E-cadherin promoter methylation. Hence, premenopausal women appeared more susceptible to these early exposures than postmenopausal women.

The study was presented on April 6 at the 2011 American Association for Cancer Research meeting in Orlando, Fla.