Environmental Toxicology and Ecological Risk Assessment

Biography

Biography: Wojciech Wasowicz

Abstract

There is a growing interest in the biological role of selenium (Se) with respect to both protection of human health and prevention of diseases, among others to cancer prevention. Epidemiological studies, including retrospective, prospective and intervention ones, show that a low Se level may increase the risk of certain cancers. However, it should be noted that there is also a relatively large number of studies, in which no effect of Se on cancer has been observed. In the light of recent studies, it may be assumed that not only low but also high Se status may be associated with an elevated cancer risk. Thus, evidence for the chemopreventive role of Se, based on the current epidemiological data, seems to be conflicting. To find an accurate explanation of this divergence, researchers have begun to study the role of Se in the development of cancer at the molecular level. It has been found that certain genetic variants of the selenoproteins' encoding genes may modify cancer risk. However, the results of these studies also remain conflicting. To sum up, most of studies on the relationship between selenium and cancer focus either on the association between Se status and cancer risk or on the association between genetic polymorphism of selenoproteins’ genes and cancer risk. Combining both types of data (concerning both dietary and genetic factors) would be more informative and valuable in the assessment of cancer risk development, which was indicated in our recent study. In the case-control study, lung cancer risk associated with Se status was compared between individuals possessing different genetic variants of 15 kDa selenoprotein (Sep15), the protein possibly involved in cancer development due to its redox activity. The preliminary results of the study indicated that Sep15 polymorphism significantly modified lung cancer susceptibility associated with Se status. Based on our findings, we conclude that studies on the relationship between diet and cancer should focus on the interactions between dietary and genetic factors rather than on the study of each factor separately. Data from such studies would be especially interested in view of the intervention trial planning. Prior to supplementation, DNA genotyping should be first performed to select individuals with certain genetic background. This would allow to avoid (at least to some extent) the study bias associated with genetic variation and to identify individuals who, due to the specific gene and nutrient interaction, are susceptible to
cancer.