Tumors due to chronic exposure to benzene and biomarkers of exposure

Abstract

Due to occupational activities, many people are exposed to carcinogenic airborne pollutants, such as benzene. Furthermore, benzene is also present in cigarette smoke. The main cancers associated with benzene, toluene, ethylbenzene, and xylenes (BTEX) are lung cancer and malignancies of the blood. At initial stages, lung cancer is often asymptomatic, but progression into metastasis is a huge clinical concern. We performed a review on possible biomarkers for monitoring increased genome instability and downregulation of the immune system in connection with overexposure to BTEX in a subgroup of workers being exposed to BTEX at Brazilian gas stations. The workers are subject to routine blood exams every semester; however, early genomic assessment is not routine. We evaluated available tests to be applied, including measuring benzene-derived metabolites in urine, determination of oxidative and inflammatory markers in blood, immunophenotypical profiling, micronucleus test, comet (single-cell gel electrophoresis) assay, (molecular) cytogenetics, chromosomal microarray, epigenetic-changes oriented tests, determination of mitochondrial (mt)DNA copy numbers, and studies on miRNA-level. However, no consensus was reached about their application and which test combination might be suited best.