Hypermethylation in Gene Promoters Are Induced by Chronic Exposure to Benzene, Toluene, Ethylbenzene and Xylenes.

BACKGROUND AND OBJECTIVE: Gas station attendants are occupationally exposed to benzene, toluene, ethylbenzene and xylene (BTEX) compounds and thus more susceptible to the biological effects of this mixture present in gasoline, especially due to the carcinogenicity of benzene. Furthermore, the harmful effects of BTEX exposure may be potentiated by genetic and epigenetic inactivation of critical genes. The objective was to evaluate such gene-BTEX interactions accessing the promoter methylation status of p14ARF, p16INK4A and GSTP1 in peripheral blood leukocyte samples. MATERIALS AND METHODS: The 59 exposed and 68 unexposed participants from Rio de Janeiro, Brazil, were included. The promoter methylation status was accessed by methylation-specific PCR (MSP) and GSTP1 Ile105Val polymorphism was investigated by PCR-restriction fragment length polymorphism (PCR-RFLP) technique. RESULTS: Both p14ARF and p16INK4A were significantly hypermethylated in exposed subjects compared to unexposed (p = 0.004 and p<0.001, respectively). Additionally, p16INK4A hypermethylation in the exposed group was correlated with chromosomal abnormalities (CAs) (p = 0.018), thus highlighting the influence of the gene-environment interactions on genome instability. Noteworthy, p16INK4A methylation was significantly associated with miscarriage among female attendants (p = 0.047), in which those who reported miscarriage exhibited hypermethylation in at least 2 of the 3 genes analyzed. The GSTP1 heterozygote genotype, which could affect the metabolism of benzene detoxification, was found in both groups but was more frequent in those occupationally exposed. No significant association was observed between GSTP1 genotypes and methylation status. CONCLUSION: Together, these findings indicate that gas station attendants with the aforementioned epigenetic and genetic profiles may be at greater risk of occupational BTEX exposure-induced genome instability, which could require concerted efforts to establish more preventive actions and constant biomonitoring in gas station attendants.

Health survey and assessment of the polymorphisms BRCA1/P871L, BRCA1/Q356R, and BRCA2/N372H in female gas station workers in Rio de Janeiro.

Gas station workers are exposed to chemicals known to be carcinogenic, especially benzene. The objective was to analyze the health problems of female gas station workers by means of sociodemographic and clinical questionnaires, and laboratorial exams. We performed the genotyping of the polymorphisms BRCA1/P871L and BRCA1/Q356R by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism, and of variant allele BRCA2/N372H through direct sequencing. The female workers showed a higher concentration of monocytes (P = 0.039); a greater number of spontaneous abortions (P = 0.025, OR = 4.977, 95% CI = 1.135-30.669); higher tobacco consumption (P = 0.013); and higher alcohol consumption (P = 0.05). The statistical analysis of the polymorphisms associated with the variables monocyte concentration and miscarriage number did not reveal a significant relationship, and smoking and spontaneous abortion were not statistically associated either. Environ. Mol. Mutagen. 58:730-734, 2017. © 2017 Wiley Periodicals, Inc.

Proteomic profile of saliva and plasma from women with impalpable breast lesions.

The present study evaluated the proteomic profile of saliva and plasma from women with impalpable breast lesions using nano-liquid chromatography-quadrupole-time-of-flight (nLC-Q-TOF) technology. Plasma and saliva from patients with fibroadenoma (n=10), infiltrating ductal carcinoma (n=10) and healthy control groups (n=8) were assessed by combinations of inter/intra-group analyses, revealing significant quantitative and qualitative differences. The major differentially-expressed proteins in the saliva of patients compared with the controls were α2-macroglobulin and ceruloplasmin, but the proteins that met the minimum fold-change and P-value cut-offs were leukocyte elastase inhibitor and α-enolase, and deleted in malignant brain tumors 1. Concerning plasma, α-2-macroglobulin and ceruplasmin were upregulated, while other proteins such as haptoglobin, hemopexin and vitamin D-binding protein were downregulated compared with the control. The changes in immune, molecular transport and signaling pathways were the most representative in the proteomic profile of the saliva and plasma. This is the first study to describe the proteome of saliva and plasma from the same women with impalpable breast lesions.