MicroRNAs (miRNAs) are a class of small, non-coding RNA molecules that can regulate gene expression, thereby affecting crucial processes in cancer development. miRNAs offer great potential as biomarkers for cancer detection because of their remarkable stability in blood and their characteristic expression in different diseases. We investigated whether quantitative RT-PCR miRNA profiling on serum could discriminate between breast cancer patients and healthy controls. We performed miRNA profiling on serum from breast cancer patients, followed by construction of ROC (Receiver Operating Characteristic) curves to determine the sensitivity and specificity of the assay. We found that seven miRNAs (miR-10b, miR-21, miR-125b, miR-145, miR-155 miR-191 and miR-382) had different expression patterns in serum of breast cancer patients compared to healthy controls. ROC curve analyses revealed that three serum miRNAs could be valuable biomarkers for distinguishing BC from normal controls. Additionally, a combination of ROC curve analyses of miR-145, miR-155 and miR-382 showed better sensitivity and specificity of our assay. miRNA profiling in serum has potential as a novel method for breast cancer detection in the Mexican population.

The entire coding regions of BRCA1 and BRCA2 were screened for mutations by heteroduplex analysis in 51 Mexican breast cancer patients. One BRCA1 and one BRCA2 truncating mutation each was identified in the group of 32 (6%) early-onset breast cancer patients ( ≤35 years). Besides these two likely deleterious mutations, eight rare variants of unknown significance, mostly in the BRCA2 gene, were detected in six of 32 (19%) early-onset breast cancer cases and in three of 17 (18%) site-specific breast cancer families, one containing a male breast cancer case. No mutations or rare sequence variants have been identified in two additional families including each an early-onset breast cancer case and an ovarian cancer patient. The two truncating mutations (BRCA1 3857delT; BRCA2 2663-2664insA) and six of the rare variants have never been reported before and may be of country-specific origin. The majority of the alterations appeared to be distinct, with only one of them being observed in more than one family.

The most prevalent female cancer across the world is breast cancer. Current established breast cancer risk factors explain only a fraction of the breast cancer cases diagnosed, and for this reason, other environmental factors have been studied. Exposure to organochlorine compounds has been linked to an increased incidence of breast cancer, although not all data have been consistent. This study was designed to evaluate the relation between polychlorinated biphenyls (PCB) exposure and breast cancer risk in Mexican women. We recruited 140 women from the General Hospital. The cases were 70 newly diagnosed women. We collected environmental and reproductive information by questionnaire. Blood samples were taken for measurement of serum levels of 20 PCB congeners. Risk of breast cancer was found to be positively associated with heavy congeners, age, postmenopausal status, family history of breast cancer and living close to an industrial facility. When PCB were grouped by structure-activity relationships, the risk of breast cancer was positively associated with groups 2b (odds ratio, OR = 1.90, 95% confidence interval, CI, 1.25-2.88), 3 (OR = 1.81, 95% CI 1.08-3.04) and group 4 (OR = 1.57, 95% CI 1.20-2.07). Among postmenopausal women, PCB levels from groups 1a, 2b, and 4 and total PCB were higher in cases, and an association between risk of breast cancer with groups 1a (OR = 7.59, 95% CI 1.1-51.4), 2b (OR = 3.7, 95% CI 1.2-11.2) and 4 (OR = 1.8, 95% CI 1.1-3.1) was found in this group of women. This study showed an association between heavy and potentially estrogenic PCB congeners and breast cancer risk.

Clinical follow up of Mexican women with early onset of breast cancer and mutations in the BRCA1 and BRCA2 genes.

Over the past decades, an increase has been described in exposure to environmental toxins; consequently, a series of studies has been carried out with the aim of identifying problems associated with health. One of the main risk factors is exposure to heavy metals. The adverse effects that these compounds exert on health are quite complex and difficult to elucidate, in that they act at different levels and there are various signaling pathways that are implicated in the mechanisms of damage. The Sertoli cells plays a role of vital importance during the process of spermatogenesis, and it has been identified as one of the principal targets of heavy metals. In the present review, cadmium, lead, and arsenic are broached as altering the physiology of the Sertoli cells, citing mechanisms that have been cited in the literature.