Occupational Exposure To Trichloroethylene And Line-1 Methylation

Trichloroethylene (TCE) is a volatile chlorinated organic compound that is commonly used in industrial settings as a degreaser. Epidemiologic studies suggest that TCE exposure is associated with an increased risk of kidney cancer and may also be associated with non-Hodgkin lymphoma. However, the mechanisms for these associations are still not clear. To evaluate the relationship between occupational exposure to trichloroethylene (TCE) and LINE-1 methylation, a measure of global methylation, we conducted a cross-sectional molecular epidemiology study of 79 workers exposed to TCE and 81 comparable unexposed controls in Guangdong, China. Personal air exposure measurements and urine samples were collected prior to phlebotomy. The urine TCE metabolite, trichloroacetic acid (TCA), was measured by liquid chromatography electrospray ionization tandem mass spectrometry in urine samples and LINE-1 methylation was assessed by pyrosequencing DNA isolated from peripheral blood. LINE-1 methylation levels [median (range) in percent] were 78.40 (75.80-81.20) in controls, 77.80 (76.10-81.00) in lower exposed, and 77.50 (74.20-80.20) in higher exposed workers based on median urine TCA level (p trend = 0.012). These results suggest that TCE may be associated with a decrease in global methylation measured by the LINE-1 assay. Gene-specific methylation is currently being conducted to follow up these findings. Citation Format: Wei Hu, Luoping Zhang, Christopher Kim, Xiaojiang Tang, Sungkyoon Kim4, Bryan Bassig, Wei-Jie Seow, Min Shen, Chuangyi Qiu, Yechen Ge, Boris Reiss, Mark Purdue, Lee Moore, Laiyu Li, Fei Yue, Hanlin Huang, Martyn T. Smith, Roel Vermeulen, Nathaniel Rothman, Qing Lan. Occupational exposure to trichloroethylene and LINE-1 methylation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 840. doi:10.1158/1538-7445.AM2015-840