*The Role of Genetic Polymorphisms in the Occupational Exposure DOI: http://dx.doi.org/10.5772/intechopen.86975*

*The Recent Topics in Genetic Polymorphisms*

**occupational risk assessment**

investigated the effects of polymorphic genes CYP2E1, EPHX1, GST-T1 and GST-M1 on the urinary concentrations of the styrene metabolites, i.e. mandelic acid (MA) and phenylglyoxylic acid (PGA), and on the ratio between MA and PGA. Here the concentrations of urinary styrene and of airborne styrene have been determined. In the exposed workers, a lower excretion of PGA and MA metabolites was detected in subjects with cytochrome P450 2E1\*5B (CYP2E1\*5B) and cytochrome P450 2E1\*6 (CYP2E1\*6) heterozygous genotype with respect to the homozygous wild type indicating the influence of SNPs on the dose biomarkers. Furthermore a reduced value of metabolite ratio (MA + PGA/urinary styrene) was observed in exposed workers with the EPHX1 Tyr113His slow/mutant allele in comparison to those with the wild-type allele. The results indicate a reduced excretion of MA + PGA, evidenced also by other authors only in association with other genotypes. This study confirmed the variability in the excretion of urinary styrene metabolites, strictly related to the individual gene polymorphisms, can significantly impact on the biological monitoring of styrene exposure. In the CYP2E1\*5B and CYP2E1\*6 heterozygous genotypes as well as in the EPHX1 slow mutant genotypes, the average excretion of MA + PGA is, respectively, reduced 20 and 35% in comparison to the wild-type population [17].

**3.2 Operative procedure and ethical use of workers' biosamples for** 

The availability of human biological samples is fundamental for the biomonitoring since it allows to estimate the exposure risk of the workers. The mostly used biosamples are whole blood with its separated fractions (plasma, serum, buffy coat, peripheral mononuclear cells, blood clot), urine, saliva, oral cell mucosa and cell components such as DNA and mRNA. In the occupational studies, biosamples are kindly donated from the workers agreeing to the biomonitoring project, provided that they give the informed consent. In Italy the biomonitoring procedure is sub-conditioned to the availability of the host manufacture company to agree the investigational study. The final purpose of the research has to be approved by the local health unit, by the research institute and, only in case of experimental clinical protocols, by the ethical committee. As volunteers the workers might join but not necessarily have to participate to the study related to the occupational health risk exposure, and they are not forced to undergo genetic screening. Workers participating to the programme agree by informed consent and are invited to fill a questionnaire to exclude all the potential confounding factors interfering with the analysis (drug assumption, alcohol consumption, smoking habit, chronic or acute diseases) before donating their biological samples. Those wishing to support the observational study are aware their specimens will be used only for the scientific purpose and will be collected, stored and used according to the ethical guidance of the Declaration of Helsinki [18]. The collection, storage and processing of the biosamples must be performed under strictly controlled procedures, in order to preserve their integrity and quality. In particular, the storage of genetic data collected in the workplace is fundamental since they contain sensitive health and non-health-related information about individuals which must be adequately protected in research as well as in clinical studies. This principle has been formalized in Europe on 27 April 2016 with the new General Data Protection Regulation (EU GDPR 2016/679), effective from 25 May 2018, which has entered into force and repealed the previous Directive 95/46/ EC for personal data protection. The aim of the regulation is to promote and harmonize the personal data protection in the EU [19]. In the occupational setting, three types of biosamples are mainly requested to the workers, i.e. whole blood, urine and buccal cells. To perform genetic analysis on the biospecimen, the workers who

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agree to donate the sample must be informed of the purpose of the research project in all the aspects; they also should understand the utility, the scope and the limit of the analysis. Workers and their supervisors or representatives are informed on the modality, procedure and scheduling related to the donation of the biosamples. For instance, in the case of urine and buccal cells, workers can themselves self-collect their specimens provided that they are informed in advance on the day of collection. The collaborating institute ensures analysis of all the data, and for the genetic results, it ensures anonymity and confidentiality, un-disclosure in public databases, exclusivity and availability to medical staff of the company if required for internal use. Most importantly the genetic data are analysed as groups and not individually in order to avoid any misinterpretation or discrimination. As stated before, the information on the susceptibility risk is not relevant at the individual level, while it becomes significant once a large number of subjects belonging to the same ethnicity are available. The genetic analysis should be scientifically validated and must not involve any kind of discrimination for the individual.
