A group of boffins led by Christine Ambrosone, PhD, Cancer Prevention and Population Sciences Program, Roswell Park Cancer Institute (RPCI) and Jenny Chang-Claude, PhD, Professor in Epidemiology at University of Heidelberg conducted the study. As a part of the research, they analysed data from 10 of 13 studies published in the last decade that involved 4,889 premenopausal and 7,033 postmenopausal women. The researchers evaluated genetic information, smoking habits and breast cancer risk.
Based on their study they concluded that women who smoked, and had slow genotypes of a specific gene called NAT2 were at an increased risk of breast cancer.
This gene produces the enzyme N-acetyltransferase 2 (NAT2) that helps break down aromatic amines - a major class of tobacco smoke carcinogens - that are then excreted from the body.
Individuals have either rapid or slow activity based upon their genotypes. People with the slower enzyme are unable to rid the body of aromatic amines as efficiently as those who have the faster enzyme. As a result, there is a greater likelihood that there will be DNA damage, and an increased possibility of breast cancer.
"These results, analyzing all studies to date, indicate that subgroups of women defined by genetic predisposition are at higher risk of breast cancer if they are exposed to tobacco smoke," said Dr. Ambrosone.
"In fact, smoking is likely to play an important role in the development of breast cancer for about 50-60% of the populations from European descent who have a form of the NAT2 gene that gets rid of aromatic amines more slowly than the rest of the population."
The study is published in the journal Cancer Epidemiology, Biomarkers and Prevention.