Role of endocrine disrupting chemicals on the tissue levels of AhR and sex steroid receptors in breast tumours

Breast cancer affects Iranian women at least one decade younger than their counterparts in othercountries and the incidence of breast fibroadenoma is growing in the last two decades in Tehran. Thisstudy aimed to compare the AhR levels in premenopausal breast cancer and breast fibroadnemo withappropriate normal groups. Possible associations of AhR with lifestyle and reproductive risk factorsand other fundamental genes of breast cancer and reproductive disorders were the other major goalsof present study. To conduct the comparisons all possible reproductive, environmental and lifestylerisk factors of mentioned diseases were recorded in 100 breast cancer, 100 breast fibroadenoma andcompared with 400 women in normal group from 2009 to 2011. AhR overexpression in epithelialcells of premenopausal patients emphasized the susceptibility of these cells to environmental inducedreproductive disorders. The AhR overexpression was contributed to ER-/PgR- immunophenotype inmalignant tissues. Weight gain (after 18 and after pregnancy), long term (>5yrs) OCP consumption,smoking, severe stress ,history of ovarian cysts, hormonal deregulations, living near PAHs producingsources, were correlated with increased risk of breast cancer and reproductive disorders and werecorrelated with elevated tissue levels of AhR. It seems that increased risk of breast cancer and otherreproductive tumours in Tehran may be the result of exposure to environmental endocrine disruptors.Long term exposure to environmental estrogens can increase the tissue levels of AhR and deregulatethe expression pattern of sex steroid receptors and other genes in target tissues.