title: [DNA methylation and telomere damage in occupational people exposed to coal tar pitch].
abstract: OBJECTIVE
  To investigate the promoter methylation of p16, FHIT and RASSF1A gene and telomere damage in the workers exposed to coal tar pitch, and to explore the effective biomarker of occupational exposure to coal tar pitch.
  
  
  METHODS
  180 cases of workers exposed to coal tar pitch in a certain carbon plant named as exposure group, and 145 healthy cases with a medical examination in the first affiliated hospital of Zhengzhou University were selected as control group. Relative telomere length in peripheral blood DNA was detected using real-time quantitative PCR, and the promoter methylation rate of p16, RASSF1A and FHIT gene in peripheral blood DNA were determined by real-time quantitative methylation specific PCR. The relative telomere length and gene promoter methylation in two groups were compared, and influencing factors were analyzed.
  
  
  RESULTS
  Relative telomere length in exposed group was lower than that in the control group, and the difference was statistically significant (Z = -5.395, P < 0.001). There was no significant difference in the promoter methylation rate of p16, FHIT and RASSF1A gene between the two groups (P > 0.05). Stratification analysis by gender, age, and smoking, we found that when the age was less than or equal to 40, the promoter methylation rate of p16 in exposed group was more than that in control group, and the difference was statistically significant (Z = -1.914, P = 0.011).
  
  
  CONCLUSIONS
  Occupational exposure to coal tar pitch may induce leukocyte DNA telomere length of human peripheral blood shortened, and may not change the promoter methylation rates of p16, FHIT and RASSF1A gene.
authors.affiliation: Labor Protection Department of Safety Management Office, Anyang Iron and steel Company Limited by Share, Anyang 455000, China.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaoran
authors.initials: X
authors.lastname: Duan
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Sihua
authors.initials: S
authors.lastname: Wang
authors.forename: Wu
authors.initials: W
authors.lastname: Yao
authors.forename: Shibin
authors.initials: S
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: E-mail: wuyongjun@zzu.edu.cn.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Wu
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000235:genetics; D003033:Coal Tar / Q000009:adverse effects*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D019175:DNA Methylation; D006801:Humans; D007962:Leukocytes / Q000187:drug effects; D009363:Neoplasm Proteins / Q000235:genetics; D016273:Occupational Exposure / Q000009:adverse effects*; D011401:Promoter Regions, Genetic; D016615:Telomere / Q000187:drug effects* / Q000648:ultrastructure; D025521:Tumor Suppressor Proteins / Q000235:genetics; D000099170:Bis(5'-adenosyl)triphosphatase
chemical_list: D017766:Acid Anhydride Hydrolases; D003033:Coal Tar; D019941:Cyclin-Dependent Kinase Inhibitor p16; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins; D000099170:Bis(5'-adenosyl)triphosphatase; C411762:RASSF1 protein, human; C583516:p12(INK4a) protein, human