Association of relative telomere length in peripheral blood in control subjects with the concentration of Bisphenol-A in urine and in patients with breast cancer -

Abstract

Background: BPA (Bisphenol-A) is an estrogen-like plastic monomer found ubiquitously in our environment. It can enter our body through different routes (oral, pulmonary and dermal) and from different sources. Very few studies were done in vitro to check the effect of BPA on telomere length, however no clinical studies were done to study the association between human exposure to Bisphenol-A and relative telomere length. Telomere length plays a critical role in maintaining genomic stability. Previous studies have shown an association between telomere length and different diseases and cancer types including breast cancer. However, different clinical studies on the association between telomere length and breast cancer risk have shown contradicting results. Aims: We aimed to study the association between urinary BPA levels and relative telomere length (RTL) in peripheral blood samples of a large Lebanese cohort. In addition to that, we wanted to explore any difference in the mean relative telomere length in the peripheral blood of non-breast cancer and breast cancer females. Moreover, we wanted to investigate the association between other variables such as age and BMI with relative telomere length in peripheral blood. Methods: After signing an informed consent, 501 Lebanese volunteers, of whom 319 were females, were recruited from Greater Beirut between February and June 2014. A fasting urine sample was collected in a glass container to avoid any exogenous BPA contamination. Peripheral whole blood was collected as well and stored along with the urine samples at -80 ºC. Urinary BPA levels were measured using HPLC-MS.Another cohort of 87 female breast cancer patients was also studied. The female breast cancer patients were recruited at the American University of Beirut Medical Center (AUBMC) between 2012 and 2013 and they signed an informed consent. Their peripheral blood was collected and stored at -80 ºC. Quantitative real-time polymerase chain reaction (PCR) was used to measure the relative telomere l