Benzene is an organic
solvent that has been used in industry for about 100 years throughout the world. Since 1973, a series of toxicological and molecular epidemiological studies on
benzene were conducted by researchers at the Chinese Academy of Preventive Medicine (CAPM) (1973-1986) and subsequently by a collaboration between the CAPM and the National Cancer Institute (NCI) in the United States that began in 1986, which was joined by investigators from the University of California at Berkeley, the University of North Carolina at Chapel Hill, and New York University. The findings demonstrated that the risk of
leukemia and
lymphoma among
benzene-exposed workers was significantly increased, with elevated risks for
leukemia present not only at higher exposure but also among workers exposed to under 10 ppm. Therefore, the
benzene permissible level was decreased to 1.8 ppm (6 mg/m(3)) and
benzene-induced
leukemia is treated as an occupational
cancer in China. The
benzene permissible level is 1.0 in the United States and in several other developed countries and it has been suggested to be decreased to 0.5 ppm (ACGIH). A number of potential
biomarkers are related to
benzene exposure and
poisoning. Some of these are
benzene oxide-
protein adducts,
chromosome aberration of lymphocytes, and GPA mutations in erythrocytes, a decrease in B cell and CD4(-)T cell counts in peripheral blood, and altered expression of CXCL16, ZNF331, JUN, and PF4 in lymphocytes. Variation in multiple
benzene metabolizing genes may be associated with risk of
benzene hematotoxicity, including
CYP2E1, MPO, NQO1, and GSTT1.