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Gastric cancer is the first cause of death for cancer in Chile. The recently identified genetic alterations in these tumors have not yielded new biomarkers for the disease. Epigenetics or the study of reversible genomic changes that do not affect protein codifying DNA sequences but cause phenotypic disturbances, is identifying new cancer biomarkers. Specifically, the loss of expression caused by the covalent link of a methyl group to carbon 5 of cytosine (DNA hypermethylation) is extensively evaluated. Performing an epigenetic evaluation of 24 genes, we have identified eight genes associated to the aggressive signet ring cell type gastric cancer, the association between APC hypermethylation and worse prognosis and BRCA1 hypermethylation association with early onset of gastric cancer. The most interesting findings are the hypermethylation of Reprimo gene in plasma as a population biomarker and the tissue over expression of p73 gene (as a consequence of hypomethylation) as a high risk indicator of progression to gastric cancer. All these findings are indicating an important role of epigenetics in the pathogenesis and early detection of gastric cancer.

El efecto de los plaguicidas sobre la salud humana, animal y ambiental es preocupación de la comunidad científica desde hace mucho tiempo. Numerosos estudios reportan que los plaguicidas no son inofensivos y que su uso puede conducir a efectos biológicos dañinos a mediano y a largo plazo, en los grupos humanos y animales expuestos, en el presente o en los descendientes. La importancia en la detección precoz del daño genético radica en que permite tomar las medidas necesarias para disminuir o suprimir la exposición al agente deletéreo cuando aún éste es reversible, y de ese modo prevenir y disminuir el riesgo de desarrollar neoplasias y otras alteraciones patológicas. En este trabajo se revisan los principales conceptos en la temática, la utilidad de los estudios de genotoxicidad y se hace referencia a los trabajos realizados en los últimos veinticinco años sobre monitoreo genético de personas expuestas laboralmente a plaguicidas. Los ensayos de genotoxicidad, que incluyen aberraciones cromosómicas, micronúcleos, intercambio de cromátidas hermanas y cometa, deberían ser considerados como herramientas indispensables en la implementación de una vigilancia médica completa en personas potencialmente expuestas a diversos contaminantes ambientales y en especial aquellas que habitan en el mismo lugar con personas que ya han desarrollado algún tipo de neoplasia en edades tempranas, con el fin de prevenir la ocurrencia de tumores de origen ambiental y especialmente laboral. The effect of pesticides on human, animal and environmental health has been cause of concern in the scientific community for a long time. Numerous studies have reported that pesticides are not harmless and that their use can lead to harmful biological effects in the medium and long term, in exposed human and animals, and their offspring. The importance of early detection of genetic damage is that it allows us to take the necessary measures to reduce or eliminate the exposure to the deleterious agent when damage is still reversible, and thus to prevent and to diminish the risk of developing tumors or other alterations. In this paper we reviewed the main concepts in the field, the usefulness of genotoxicity studies and we compiled studies performed during the last twenty years on genetic monitoring of people occupationally exposed to pesticides. We think that genotoxicity tests, including that include chromosomal aberrations, micronucleous, sister chromatid exchanges and comet assays, should be considered as essential tools in the implementation of complete medical supervision for people exposed to potential environmental pollutants, particularly for those living in the same place as others who where others have already developed some type of malignancy. This action is particularly important at early stages to prevent the occurrence of tumors, especially from environmental origins.