Dietary exposure to mercury and its relation to cytogenetic instability in populations from "La Mojana" region, northern Colombia.

Fish consumption and chronic exposure to low doses of mercury (Hg) seems to activate several molecular mechanisms leading to carcinogenic and/or teratogenic processes. However, Hg genotoxic effects on humans are not completely described. In the present study, we assessed cytogenetic damage in isolated human peripheral lymphocytes using the cytokinesis-block micronucleus cytome assay (CBMN-Cyt), micronucleus formation with anti-kinetochore antibody (CREST staining), levels of total Hg in hair (T-Hg), fish consumption, and estimated Hg dose. The study comprised 39 non-exposed, and 73 residents from La Mojana region, an area with a well-documented Hg contamination. Data showed a significant increase in micronuclei (MNBN), nucleoplasmic bridges (NPB), and necrotic and apoptotic cell frequencies in residents of "La Mojana." The overall mean T-Hg level in hair for exposed residents was 1.12 ± 0.94 mg kg-1 and 0.15 ± 0.05 in individuals from the reference area. Approximately 40% of analyzed individuals showed T-Hg levels that exceeded US Environmental Protection Agency (USEPA) reference dose. Increased T-Hg levels in hair were related to increased MNBN frequencies and high fish consumption. Other cellular markers, such as necrotic and apoptotic cell frequencies, were also correlated with high fish intake and T-Hg contents. Results of the CREST staining demonstrated that in vivo exposure to Hg induces genetic instability by chromosome fragment loss (clastogenic). Additionally, a high average intake of some fish species, particularly with carnivorous habits like Caquetaia kraussii, Hoplias malabaricus, and Sorubin cuspicaudus, seems to increase MNBN frequencies significantly.

Evaluation of oxidative and methylating DNA damage in painters occupationally exposed to organic solvents and paints / Evaluación del daño oxidativo y por metilación del ADN de pintores expuestos ocupacionalmente a solventes orgánicos y pinturas

Introduction: The exposure to organic solvents and paints has been associated with genotoxicity and a greater risk of neoplasms. However, the type of DNA damage induced in humans by the exposure to these compounds, which would help explain the mechanisms of their genotoxicity, is still not fully characterized. Due to inadequate practices of occupational safety, car painters in the informal sector are a highly exposed group to organic solvents and paints. Objective: To identify the oxidative and methylating damage in the DNA of lymphocytes of car painters exposed to organic solvents and paints. Materials and methods: Isolated peripheral blood lymphocytes from 62 painters and 62 unexposed subjects were analyzed by the modified high-throughput comet assay with the Fpg and AlkA enzymes. The categories used for the evaluation of the DNA damage were basal damage (without enzymes), oxidative and methylating damage. The measurement parameter used to establish the damage was the percentage of DNA in the tail. Results: The percentage of DNA in the tail was higher in the exposed group compared to the unexposed group (p<0.05). In the exposed group, this percentage was higher in the oxidative damage category than the baseline (16.50 vs. 12.87; p<0.001), whereas methylating damage did not show significant differences (14.00 vs. 12.87; p>0.05). Conclusion: In this study, exposure to organic solvents and paints was associated with an increase in oxidative lesions in the DNA of car painters' lymphocytes, such as the production of 8-oxodG and other formamidopyrimidine products which are considered highly mutagenic.

Introducción. La exposición a solventes orgánicos y pinturas se ha asociado con efectos genotóxicos y mayor riesgo de neoplasias. Sin embargo, aún no se ha caracterizado bien el tipo de daño que esta exposición induce en el ADN humano, ni los mecanismos por los cuales se genera. Uno de los grupos con mayor exposición a dichos solventes y pinturas son los pintores de automóviles del sector informal que trabajan sin adecuadas prácticas de seguridad ocupacional. Objetivo. Determinar el daño oxidativo y por metilación del ADN de linfocitos de pintores de automóviles expuestos a solventes orgánicos y pinturas. Materiales y métodos. Se analizaron linfocitos aislados de sangre periférica de 62 pintores y 62 sujetos no expuestos mediante el ensayo cometa de gran eficiencia acoplado a las enzimas Fpg y AlkA. Las categorías de daño en el ADN evaluadas fueron el daño basal (sin enzimas), el daño oxidativo y el daño por metilación, y el parámetro de medición, el porcentaje de ADN en la cola. Resultados. El porcentaje de ADN en la cola fue mayor en el grupo expuesto con respecto al no expuesto (p<0,05). En el grupo expuesto, dicho porcentaje fue mayor en la categoría de daño oxidativo comparado con la del basal (16,50 Vs. 12,87; p<0,001), en tanto que en el daño por metilación no se encontraron diferencias significativas (14,00 Vs. 12,87; p>0,05). Conclusión. La exposición a solventes orgánicos y pinturas se asoció con el aumento de las lesiones oxidativas del ADN de los linfocitos de pintores de automóviles, tales como la producción de 8-oxo-2'-desoxiguanosina (8-oxodG) y otros productos formamidopirimidina, los cuales se consideran considerablemente mutagénicos.

Evaluación del daño oxidativo y por metilación del ADN de pintores expuestos ocupacionalmente a solventes orgánicos y pintura / Evaluation of oxidative and methylating DNA damage in painters occupationally exposed to organic solvents and paints

Resumen Introducción. La exposición a solventes orgánicos y pinturas se ha asociado con efectos genotóxicos y mayor riesgo de neoplasias. Sin embargo, aún no se ha caracterizado bien el tipo de daño que esta exposición induce en el ADN humano, ni los mecanismos por los cuales se genera. Uno de los grupos con mayor exposición a dichos solventes y pinturas son los pintores de automóviles del sector informal que trabajan sin adecuadas prácticas de seguridad ocupacional. Objetivo. Determinar el daño oxidativo y por metilación del ADN de linfocitos de pintores de automóviles expuestos a solventes orgánicos y pinturas. Materiales y métodos. Se analizaron linfocitos aislados de sangre periférica de 62 pintores y 62 sujetos no expuestos mediante el ensayo cometa de gran eficiencia acoplado a las enzimas Fpg y AlkA. Las categorías de daño en el ADN evaluadas fueron el daño basal (sin enzimas), el daño oxidativo y el daño por metilación, y el parámetro de medición, el porcentaje de ADN en la cola. Resultados. El porcentaje de ADN en la cola fue mayor en el grupo expuesto con respecto al no expuesto (p<0,05). En el grupo expuesto, dicho porcentaje fue mayor en la categoría de daño oxidativo comparado con la del basal (16,50 Vs. 12,87; p<0,001), en tanto que en el daño por metilación no se encontraron diferencias significativas (14,00 Vs. 12,87; p>0,05). Conclusión. La exposición a solventes orgánicos y pinturas se asoció con el aumento de las lesiones oxidativas del ADN de los linfocitos de pintores de automóviles, tales como la producción de 8-oxo-2'-desoxiguanosina (8-oxodG) y otros productos formamidopirimidina, los cuales se consideran considerablemente mutagénicos.

Abstract Introduction: The exposure to organic solvents and paints has been associated with genotoxicity and a greater risk of neoplasms. However, the type of DNA damage induced in humans by the exposure to these compounds, which would help explain the mechanisms of their genotoxicity, is still not fully characterized. Due to inadequate practices of occupational safety, car painters in the informal sector are a highly exposed group to organic solvents and paints. Objective: To identify the oxidative and methylating damage in the DNA of lymphocytes of car painters exposed to organic solvents and paints. Materials and methods: Isolated peripheral blood lymphocytes from 62 painters and 62 unexposed subjects were analyzed by the modified high-throughput comet assay with the Fpg and AlkA enzymes. The categories used for the evaluation of the DNA damage were basal damage (without enzymes), oxidative and methylating damage. The measurement parameter used to establish the damage was the percentage of DNA in the tail. Results: The percentage of DNA in the tail was higher in the exposed group compared to the unexposed group (p<0.05). In the exposed group, this percentage was higher in the oxidative damage category than the baseline (16.50 vs. 12.87; p<0.001), whereas methylating damage did not show significant differences (14.00 vs. 12.87; p>0.05). Conclusion: In this study, exposure to organic solvents and paints was associated with an increase in oxidative lesions in the DNA of car painters' lymphocytes, such as the production of 8-oxodG and other formamidopyrimidine products which are considered highly mutagenic.

Genetic damage in environmentally exposed populations to open-pit coal mining residues: Analysis of buccal micronucleus cytome (BMN-cyt) assay and alkaline, Endo III and FPG high-throughput comet assay.

DNA and chromosomal damage in individuals occupationally exposed to coal mining residues have repeatedly been reported in lymphocytes and epithelial cells, suggesting a systemic exposure-response in which generation of oxidative damage may play a major role. Nevertheless, the understanding of this mechanism is still incomplete, particularly in regard to environmental exposures. This study aimed to evaluate DNA damage using the cytome assay (BMN-cyt) in buccal cells and its relation to primary and oxidative DNA damage in lymphocytes, assessed by the high-throughput alkaline and modified (FPG-ENDO III) Comet assay in individuals with environmental exposure to coal mining residues in northern Colombia. Considering metals from coal mining activities as the main source of reactive oxygen species (ROS) generation, the concentrations of inorganic elements in blood samples was also assessed. The analysis revealed that frequencies of BMN-cyt parameters related to DNA damage (micronuclei), cytokinesis (binucleated cells) and cell death (condensed chromatin, karyorrhexis, pyknosis and karyolysis) were significantly higher in individuals that were environmentally exposed to coal compared to the unexposed group. The level of % Tail DNA in the alkaline and the modified Comet assay was 4.0 and 4.3 times higher among exposed individuals than in unexposed controls respectively. Increased MN frequencies in buccal cells were correlated with increased %Tail DNA in alkaline and FPG Comet assay. Additionally, exposed individuals had higher concentrations of Cr, Ni, Mn, and Br in the blood compared to unexposed controls. %Tail DNA in alkaline Comet assay was highly correlated with Al, Mn, and Br concentrations, while %Tail DNA in the FPG Comet assay correlated with Mn levels. These results suggest that oxidative damage, particularly purine oxidation, may play an essential role in DNA damage in individuals exposed to coal residues and that some inorganic elements are related to this effect.

Cytogenetic instability in populations with residential proximity to open-pit coal mine in Northern Colombia in relation to PM10 and PM2.5 levels.

Epidemiological studies indicate that living in proximity to coal mines is correlated with numerous diseases including cancer, and that exposure to PM10 and PM2.5 components could be associated with this phenomenon. However, the understanding of the mechanisms by which PM exerts its adverse effects is still incomplete and comes mainly from studies in occupationally exposed populations. The aims of this study were to: (1) evaluate DNA damage in lymphocytes assessing the cytokinesis-block micronucleus cytome assay (CBMN-cyt) parameters; (2) identify aneugenic or clastogenic effects in lymphocytes of exposed populations using CREST immunostaining for micronuclei; (3) evaluate multi-elemental composition of atmospheric particulate matter; and (4) verify relation between the DNA damage and PM2.5 and PM10 levels around the mining area. Analysis revealed a significant increase in micronuclei frequency in binucleated (MNBN) and mononucleated (MNMONO) cells of individuals with residential proximity to open-pit coal mines compared to residents from non-mining areas. Correlation analysis demonstrated a highly significant association between PM2.5 levels, MNBN frequencies and CREST+ micronuclei induction in exposed residents. These results suggest that PM2.5 fraction generated in coal mining activities may induce whole chromosome loss (aneuploidy) preferentially, although there are also chromosome breaks. Analysis of the chemical composition of PM2.5 by PIXE demonstrated that Si, S, K and Cr concentrations varied significantly between coal mining and reference areas. Enrichment factor values (EF) showed that S, Cr and Cu were highly enriched in the coal mining areas. Compared to reference area, mining regions had also higher concentrations of extractable organic matter (EOM) related to nonpolar and polar compounds. Our results demonstrate that PM2.5 fraction represents the most important health risk for residents living near open-pit mines, underscoring the need for incorporation of ambient air standards based on PM2.5 measures in coal mining areas.

Polymorphisms in metabolism and repair genes affects DNA damage caused by open-cast coal mining exposure.

Increasing evidence suggest that occupational exposure to open-cast coal mining residues like dust particles, heavy metals and Polycyclic Aromatic Hydrocarbons (PAHs) may cause a wide range of DNA damage and genomic instability that could be associated to initial steps in cancer development and other work-related diseases. The aim of our study was to evaluate if key polymorphisms in metabolism genes CYP1A1Msp1, GSTM1Null, GSTT1Null and DNA repair genes XRCC1Arg194Trp and hOGG1Ser326Cys could modify individual susceptibility to adverse coal exposure effects, considering the DNA damage (Comet assay) and micronucleus formation in lymphocytes (CBMN) and buccal mucosa cells (BMNCyt) as endpoints for genotoxicity. The study population is comprised of 200 healthy male subjects, 100 open-cast coal-mining workers from "El Cerrejón" (world's largest open-cast coal mine located in Guajira - Colombia) and 100 non-exposed referents from general population. The data revealed a significant increase of CBMN frequency in peripheral lymphocytes of occupationally exposed workers carrying the wild-type variant of GSTT1 (+) gene. Exposed subjects carrying GSTT1null polymorphism showed a lower micronucleus frequency compared with their positive counterparts (FR: 0.83; P=0.04), while BMNCyt, frequency and Comet assay parameters in lymphocytes: Damage Index (DI) and percentage of DNA in the tail (Tail % DNA) were significantly higher in exposed workers with the GSTM1Null polymorphism. Other exfoliated buccal mucosa abnormalities related to cell death (Karyorrhexis and Karyolysis) were increased in GSTT/M1Null carriers. Nuclear buds were significantly higher in workers carrying the CYP1A1Msp1 (m1/m2, m2/m2) allele. Moreover, BMNCyt frequency and Comet assay parameters were significantly lower in exposed carriers of XRCC1Arg194Trp (Arg/Trp, Trp/Trp) and hOGG1Ser326Cys (Ser/Cys, Cys/Cys), thereby providing new data to the increasing evidence about the protective role of these polymorphisms. This modulation may involve specific and differentiated pathways in different tissues that also may cause a differential sensitivity related to differential induction of some enzymes.

Assessment of DNA damage in car spray painters exposed to organic solvents by the high-throughput comet assay.

Occupational exposure as a painter is associated with DNA damage and development of cancer. Comet assay has been widely adopted as a sensitive and quantitative tool for DNA damage assessment at the individual cell level in populations exposed to genotoxics. The aim of this study was to assess the application of the high-throughput comet assay, to determine the DNA damage in car spray painters. The study population included 52 car spray painters and 52 unexposed subjects. A significant increase in the %TDNA median (p < 0.001) was observed in the exposed group in comparison to the unexposed group. Neither age (%TDNA: p = 0.913) nor time of exposure (%TDNA: p = 0.398) were significantly correlated with DNA damage. The car spray painters who consumed alcohol did not show a significant increase in DNA damage compared to nonalcohol consumers (p > 0.05). The results showed an increase in DNA breaks in car spray painters exposed to organic solvents and paints; furthermore, they demonstrated the application of high-throughput comet assay in an occupational exposure study to genotoxic agents.

Assessment of genomic damage and repair on human lymphocytes by paint thinner in vitro.

Paint thinners are organic-solvent complex mixtures frequently used by car painters around the world in industries and shops. Some studies have revealed the oxidative effect induced by thinner inhalation; however, its genotoxic effect is poorly studied. The aim of this study was to assess the cytotoxicity, genomic damage and DNA repair in vitro induced by commercial paint thinner 0.14 in human lymphocytes. Cytotoxicity was determined by cell-viability analysis with trypan blue after 4 h treatment with different thinner concentrations (0.025 to 1.2 µL/mL). Genomic damage was evaluated by means of the alkaline single-cell gel electrophoresis (SCGE; pH > 13) in treated cultures after 1 h with three low-cytotoxic thinner concentrations (0.05, 0.1 and 0.2 µL/mL). In order to evaluate the genomic DNA repair, one set of SCGE slides was prepared immediately after treatment, and another one was prepared after 4 h of liquid-holding recovery. A significant level of cytotoxicity was observed over the entire concentration range of paint thinner in lymphocytes (F = 175.98; p ≤ 0.001). In the SCGE % tail DNA assessment, a significant increase of lymphocyte genomic damage was evidenced (F = 72.32; p < 0.001). In addition, we found a significant decrease in the % tail DNA in thinner-treated cells after liquid-holding recovery period (all p < 0.05), demonstrating that DNA primary lesions induced by low-cytotoxic thinner concentrations are efficiently repaired. In conclusion, thinner components induce cytotoxicity and genomic damage in human lymphocytes under the study conditions, possibly by oxidative and alkylative DNA damage.

The effect of genetic admixture in an association study: genetic polymorphisms and chromosome aberrations in a Colombian population exposed to organic solvents.

The human population is heterogeneous in genetic susceptibility, chromosomal instability and disease risk; all factors which depend on inherited genetic constitution and acquired nongenetic environmental and occupational factors. Recently, special attention has been directed to the identification of sources of potential bias in population studies of gene-environment interactions including genetic admixture. The aim of this study was to evaluate the effect of genetic admixture in the association of genetic polymorphisms and chromosome aberrations (CA) in a population exposed to organic solvents. We assessed genetic admixture via 34 genetic ancestry informative markers (AIMs) in 398 Colombian individuals. We report a statistically significant difference of higher CA frequency in individuals' below-average European component, and in individuals' above-average Native American component after adjusting for covariates. In addition, the confounding risk ratio values are ≥10% than the adjusted risk ratio, suggesting that population stratification is a confounding factor in this gene-environment association study. Furthermore, after adjusting for individual admixture proportions and covariates, the results demonstrate that glutathione-S-transferase M1 (GSTM1)-null is associated with CA frequency increase. These results suggest that gene-environment association studies that involve recently admixed populations should take into consideration population stratification as a confounding factor and suggest GSTM1-null as a genetic marker associated with CA frequency increase.

Genotoxic and clastogenic effects of monohaloacetic acid drinking water disinfection by-products in primary human lymphocytes.

The haloacetic acids (HAAs) are the second-most prevalent class of drinking water disinfection by-products formed by chemical disinfectants. Previous studies have determined DNA damage and repair of HAA-induced lesions in mammalian and human cell lines; however, little is known of the genomic DNA and chromosome damage induced by these compounds in primary human cells. The aim of this study was to evaluate the genotoxic and clastogenic effects of the monoHAA disinfection by-products in primary human lymphocytes. All monoHAAs were genotoxic in primary human lymphocytes, the rank order of genotoxicity and cytotoxicity was IAA > BAA >> CAA. After 6 h of repair time, only 50% of the DNA damage (maximum decrease in DNA damage) was repaired compared to the control. This demonstrates that primary human lymphocytes are less efficient in repairing the induced damage by monoHAAs than previous studies with mammalian cell lines. In addition, the monoHAAs induced an increase in the chromosome aberration frequency as a measurement of the clastogenic effect of these compounds. These results coupled with genomic technologies in primary human cells and other mammalian non-cancerous cell lines may lead to the identification of biomarkers that may be employed in feedback loops to aid water chemists and engineers in the overall goal of producing safer drinking water.

Assessment of DNA damage in coal open-cast mining workers using the cytokinesis-blocked micronucleus test and the comet assay.

Coal mining is one of the most important causes of environmental pollution, as large quantities of coal dust particles are emitted. Colombia-South America has large natural coal reserves and "El Cerrejón" is the world's largest open-cast mine located in the northern department of Guajira. The aim of the present study was to evaluate genotoxic effects in a population exposed to coal residues from the open-cast mine "El Cerrejón". 100 exposed workers and 100 non-exposed control individuals were included in this study. The exposed group was divided according to different mining area activities: (i). Transport of extracted coal, (ii). Equipment field maintenance, (iii). Coal stripping and, (iv). Coal embarking. Blood samples were taken to investigate biomarkers of genotoxicity, specifically, primary DNA damage as damage index (DI), tail length and% of tail DNA using the Comet assay (alkaline version) and chromosome damage as micronucleus (MN) frequency in lymphocytes. Both biomarkers showed statistically significantly higher values in the exposed group compared to the non-exposed control group. No difference was observed between the exposed groups executing different mining activities. These results indicate that exposure to coal mining residues may result in an increased genotoxic exposure in coal mining workers. We did not find a correlation between age, alcohol consumption and service time with the biomarkers of genotoxicity. Our results are the first data of genotoxic effects induced by coal mining exposure in Colombia, and thus, contribute to the exploration of test batteries use for monitoring of exposed populations and may stimulate designing control, hygiene and prevention strategies for occupational health risk assessment in developing countries.

Chromosome aberrations in workers exposed to organic solvents: Influence of polymorphisms in xenobiotic-metabolism and DNA repair genes.

Organic solvents are widely used as diluents or thinners for oil-paints, gasoline and other organic mixtures. We evaluated chromosome aberrations (CAs) in lymphocytes of 200 workers exposed to organic solvents and 200 referents and the influence of polymorphisms in xenobiotic-metabolism (CYP2E1, GSTM1 and GSTT1) and in DNA repair genes (XRCC1(194) Arg/Trp, XRCC1(280) Arg/His, XRCC1(399) Arg/Gln and XRCC3(241) Thr/Met). Polymorphisms were determined by PCR-RFLP. Poisson regression analysis indicates a significant CA frequency increase in exposed workers, representing a higher risk in relation to the matched referent (RR 2.15, 95% CI 1.21-1.53, p<0.001). The CA frequency in exposed workers was influenced by the polymorphic genotypes: GSTM1 null (RR 1.33, 95% CI 1.31-1.69, p<0.001), XRCC1(194) Arg/Trp, Trp/Trp (RR 1.23, 95% CI 1.08-1.40, p<0.001) and by the wild genotypes CYP2E1 C1/C1 (RR 1.20, 95% CI 1.05-1.37, p<0.001), GSTT1 positive (RR 1.49, 95% CI 1.31-1.69, p<0.001), XRCC1(280) Arg/Arg (RR 1.44, 95% CI 1.26-1.64, p<0.001) and XRCC1(241) Thr/Thr (RR 1.54, 95% CI 1.34-1.76, p=0.001). We contribute to the follow-up predictive value of individual susceptibility biomarkers and their CA frequency influence during occupational organic solvent exposure. We provide tools for surveillance and prevention strategies to reduce potential health risks in countries with a large population of car painters not using protection devices and limited organic solvents use control.

Exposición ocupacional, biomarcadores de riesgo de cáncer en los programa de vigilancia epidemiológica ocupacional para la prevención / Occupational exhibition, biomarcadores of risk of cancer in the Programmes of Occupational Epidemiological surveillance for the prevention

Según la IARC, existe evidencia suficiente en humanos y en animales de carcinogenicidad por la exposición ocupacional. La exposición a agentes mutagénicos/carcinogénicos ocurre principalmente en el lugar de trabajo. Datos epidemiológicos y de monitoreo genético han evidenciado un mayor riesgo cáncer asociado con la exposición ocupacional a los solventes orgánicos,metales pesados y plaguicidas. La Epidemiología Ocupacional Molecular, utilizando nuevos biomarcadores (exposición, efecto y susceptibilidad), ha revolucionado la investigación e identificación de individuos y poblaciones susceptibles en mayor riesgo de desarrollar problemas de salud por la exposición ocupacional. Las pruebas de alteraciones cromosómicas (AC), micronúcleos (MN) e intercambio de cromátidas hermanas (ICHs) en linfocitos de sangre periférica han sido empleadas para identificar efectos precoces y riesgo de cáncer, inducidos por agentes genotóxicos. Es bien claro que las alteraciones cromosómicas constituyen el evento inicial en el proceso de la Carcinogénesis y pueden además, estar asociadas con diferentes problemas de salud, como reproductivos, defectos genéticos transmisibles y no transmisibles, abortos, problemas de esterilidad entre otros. La prueba de alteraciones cromosómicas ha sido empleada rutinariamente para detectar actividad genotóxica de agentes potencialmente peligrosos y para la predicción de potenciales problemas de salud como el cáncer. La ventaja de esta prueba reside en la posibilidad de evaluar daños genéticos (en linfocitos), no reparados y acumulados durante varios años de exposición y expresados luego de sucederse una primera división celular In vitro. Estudios prospectivos de cohorte, realizados en Italia y el Norte de Europa y un caso control en Taiwán mostraron que las ACs registradas en linfocitos de sangre periférica de individuos sanos, son predictivas de riesgo de cáncer (modulado por factores genéticos y estilos de vida). Individuos con una mayor frecuencia de AC mostraron tener el doble de riesgo de cáncer que los individuos con menores frecuencias.

According to IARC, there is enough evidence of carcinogenicity due to occupational exposition in both animals and humans. Exposition to mutagenic/carcinogenic agents occurs mainly at the work place. Epidemiological data and genetic monitoring have shown evidence of a higher risk of cancer associated to occupational exposure to organic solvents, heavy metals, and plaguicides. Through new biomarkers (exposition, effect and susceptibility) Molecular Occupational Epidemiology has revolutionized the research and identification of susceptible individuals and populations in higher risk of developing health problems due to occupational exposure. Chromosomal alterations testing (AC), micronuclei (MN) and sister chromatid exchange (ICHs) in peripheral blood lymphocytes have been employed to identify early effects and cancer risk, induced by genotoxic agents. It is clear the chromosomal alterations constitute the initial event in the Carcinogenesis process and can also be associated to different health problems such as reproductive, transmissible and not transmissible genetic effects, miscarriage, and sterility problems amongst other. The chromosomal alterations test has been employed routinely to detect genotoxic activity of potentially dangerous agents and to predict potential health problems such as cancer. The advantaje of this test lies on the possibility of evaluating genetic damages (in lymphocytes), not repaired, and accumulated durinf several years of exposition and expressed after the first in vitro cellular division. Prospective cohort studies carried out in Italy and North Europe and a control case in Taiwan shown ACs registered in peripheral blood lymphocytes of healthy individuals predict cancer risk (modulated by genetic factors and lifestyles). Individuals with a higher AC frequency showed twice as much risk of developing cancer when compared to those with lower frequencies.