Exposure to air pollution early in life and when a woman gives birth to her first child may alter her DNA and may be associated with premenopausal breast cancer later in life, researchers at the University at Buffalo have shown.
The findings indicated that higher air pollution exposure at birth may alter DNA methylation, which may increase levels of E-cadherin, a protein important to the adhesion of cells, a function that plays an essential role in maintaining a stable cellular environment and assuring healthy tissues.
Methylation is a chemical process that has been implicated in determining which genes in a cell are active, a process essential to normal cellular function.
"To our knowledge, this is the first study to examine exposure to ambient air pollution at key points in a woman's lifetime," said lead investigator Katharine Dobson, an epidemiology doctoral student and research assistant in UB's Department of Social and Preventive Medicine.
"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 Dobson.
"We found that decreased E-cadherin promoter methylation was associated with higher exposure at birth, and increased p16 methylation with higher exposure at the time of a first child birth," said Dobson.
"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," added Dobson.
The study has been presented at the 2011 American Association for Cancer Research meeting in Orlando, Fla.