Background: Oxidants and inflammation agents are predisposing factors for the development of prostate cancer. As a chemical warfare, sulfur mustard (SM) can cause cancer through various pathways mainly increased production of oxidants and inflammation. Due to high incidence of cancer in SM victims, concentration of prostate specific antigen (PSA) in SM victims was evaluated and compared with the control group.
Methods: This study was conducted on 150 subjects exposed to SM as the Iranian chemical victim group and 150 non-exposed healthy subjects matched for age and sex, as the control group. The serum concentration of PSA was measured by Enzyme-linked Immunosorbent assay. 
Results: According to spirometry results, the SM exposure rate in the chemical victim group was mild, moderate, and severe in 66%, 27% and 7%, respectively. The mean time elapsed from exposure to SM in case group was 30 years. 100% of the victims had consumed N-acetylcysteine for alleviating symptoms due to exposure to SM. Decreased concentration of PSA in SM victims compared with control group was observed; even non-significant. (0.728 vs 0.844 ng/ml, P=0.103). Conclusion: PSA concentrations were expected to increase in SM victims, but in our study an opposite result was observed. It is assumed that consumption of N-acetylcysteine with known anti-inflammatory features, mild exposure and shorter period of time elapsed from exposure to SM may be the reasons for this results. Further studies on these subjects seem to be necessary to prove the efficacy of antioxidants such as N-acetylcysteine in prevention of prostate cancer in subjects who have the history of SM exposure.