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Inherited GSTM1 and NAT2 defects as concurrent risk modifiers in asbestos-related human malignant mesothelioma
A Hirvonen1, K Pelin, L Tammilehto
1Department of Industrial Hygiene and Toxicology, Finnish Institute of Occupational Health, Helsinki.
Abstract:
Besides asbestos exposure, the factors that determine susceptibility to malignant mesothelioma are unknown. We evaluated the risk of GSTM1 null genotype and slow acetylation-associated NAT2 genotype for malignant mesothelioma in relation to asbestos exposure. Both the GSTM1 null genotype and the NAT2 slow acetylator genotype placed individuals at about 2-fold increased risk of developing malignant mesothelioma [odds ratio (OR) = 1.8, 95% confidence interval (CI) = 1.0-3.5 and OR = 2.1, 95% CI = 1.1-4.1, for the GSTM1 and NAT2 genes, respectively]. When the patients were divided into low/moderate and high exposure groups according to their asbestos exposure histories, the effect of the at-risk genotypes was mostly attributable to the high exposure groups (OR = 2.3, 95% CI = 1.0-5.6 and OR = 3.7, 95% CI = 1.3-10.2, for the GSTM1 and NAT2 genes, respectively). The individuals with combined GSTM1 and NAT2 defects had about a 4-fold risk of developing malignant mesothelioma compared to those with the GSTM1 gene and NAT2 fast acetylator genotype (OR = 3.6; 95% CI = 1.3-9.6). Moreover, the risk among subjects highly exposed to asbestos with the double at-risk genotype was more than 7-fold greater compared to those with the more beneficial genotypes of both GSTM1 and NAT2 genes (OR = 7.4; 95% CI = 1.6-34.0).
Insights
Genetic factors like GSTM1 null and NAT2 slow acetylation genotypes increase malignant mesothelioma risk, especially with high asbestos exposure. Combined genetic defects significantly elevate risk in asbestos-exposed individuals.
Area of Science:
- Environmental Health
- Genetic Epidemiology
- Occupational Medicine
Background:
- Malignant mesothelioma susceptibility is largely unknown beyond asbestos exposure.
- Genetic variations may influence individual risk for asbestos-related diseases.
Purpose of the Study:
- To investigate the association between GSTM1 null and NAT2 slow acetylator genotypes and malignant mesothelioma risk.
- To evaluate the combined effect of these genotypes and asbestos exposure levels on disease risk.
Main Methods:
- Case-control study evaluating GSTM1 and NAT2 genotypes in relation to asbestos exposure.
- Analysis of odds ratios (OR) and 95% confidence intervals (CI) for genotype-specific and combined risks.
- Stratification by low/moderate and high asbestos exposure levels.
Main Results:
- GSTM1 null genotype associated with ~2-fold increased mesothelioma risk (OR=1.8).
- NAT2 slow acetylator genotype associated with ~2-fold increased risk (OR=2.1).
- Combined defects showed a 4-fold risk (OR=3.6), rising to over 7-fold in highly asbestos-exposed individuals (OR=7.4).
Conclusions:
- GSTM1 null and NAT2 slow acetylator genotypes are significant risk factors for malignant mesothelioma.
- The risk associated with these genotypes is amplified by high asbestos exposure.
- Combined genetic susceptibility and high asbestos exposure dramatically increase malignant mesothelioma risk.