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

Document Type: Original Article

Authors

1 Dept. of Toxicology & Pharmacology, Islamic Azad University, Pharmaceutical Sciences Branch, Tehran, Iran

2 Pharmaceutical Sciences Research Center, Islamic Azad University, Pharmaceutical Sciences Branch, Tehran, Iran

Abstract

Breast cancer affects Iranian women at least one decade younger than their counterparts in other
countries and the incidence of breast fibroadenoma is growing in the last two decades in Tehran. This
study aimed to compare the AhR levels in premenopausal breast cancer and breast fibroadnemo with
appropriate normal groups. Possible associations of AhR with lifestyle and reproductive risk factors
and other fundamental genes of breast cancer and reproductive disorders were the other major goals
of present study. To conduct the comparisons all possible reproductive, environmental and lifestyle
risk factors of mentioned diseases were recorded in 100 breast cancer, 100 breast fibroadenoma and
compared with 400 women in normal group from 2009 to 2011. AhR overexpression in epithelial
cells of premenopausal patients emphasized the susceptibility of these cells to environmental induced
reproductive disorders. The AhR overexpression was contributed to ER-/PgR- immunophenotype in
malignant 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 producing
sources, were correlated with increased risk of breast cancer and reproductive disorders and were
correlated with elevated tissue levels of AhR. It seems that increased risk of breast cancer and other
reproductive 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 deregulate
the expression pattern of sex steroid receptors and other genes in target tissues.

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