Cancer Markers Associated With Occupational Exposure to Trichloroethylene

Background: * Trichloroethylene (TCE) is a solvent used in many medical and industrial processes. * TCE is a carcinogen (causes cancer) in rats, but its carcinogenicity in humans is unclear. There is some evidence of increased liver and kidney cancers and of an association with non-Hodgkin lymphoma in studies of workers exposed to TCE. * The carcinogenicity and regulation of TCE is a matter of continuing debate. Objectives: * To determine if TCE exposure is associated with higher levels of genetic aberrations in certain white blood cells called lymphocytes. * To determine if TCE exposure affects lymphocyte subsets and levels of certain hormones called cytokines. Eligibility: Workers exposed to two different levels of exposure to TCE and unexposed workers in Guangdong Province, China. Design: * 45 workers exposed to more than 25 parts per million (ppm) TCE, 30 workers exposed to from 10 to less than 25 ppm TCE and 45 unexposed workers will be enrolled. * Subjects wear small instruments at work that measure chemicals in the air for 1 or 2 days during the 2-week study period. Exposed workers also wear several small skin patches on one of the two days. * Subjects provide blood and urine samples. * Subjects answer a questionnaire about work, smoking and drinking, use of medicines, medical history, general health, hobbies, and exposure to radiation and exposure to various substances at home.