Corvalán R Alejandro
Rev Med Chil. 2013 Dec;141(12):1570-7. doi: 10.4067/S0034-98872013001200011.
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.
胃癌是智利癌症死亡的首要原因。近期在这些肿瘤中发现的基因改变尚未产生该疾病的新生物标志物。表观遗传学，即对不影响蛋白质编码DNA序列但会导致表型紊乱的可逆基因组变化的研究，正在识别新的癌症生物标志物。具体而言，广泛评估了由甲基与胞嘧啶的5号碳共价连接引起的表达缺失（DNA高甲基化）。通过对24个基因进行表观遗传学评估，我们已鉴定出与侵袭性印戒细胞型胃癌相关的8个基因、APC高甲基化与较差预后之间的关联以及BRCA1高甲基化与胃癌早发之间的关联。最有趣的发现是血浆中Reprimo基因的高甲基化作为一种群体生物标志物，以及p73基因的组织过表达（由于低甲基化）作为胃癌进展的高风险指标。所有这些发现都表明表观遗传学在胃癌的发病机制和早期检测中起着重要作用。
