Morimoto C Y, Tedardi M V, da Fonseca I I M, Kimura K C, Sanches D S, Epiphanio T F, de Francisco Strefezzi R, Dagli M L Z
Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
School of Animal Science and Food Engineering, University of São Paulo, Pirassununga, Brazil.
Vet Comp Oncol. 2017 Sep;15(3):1014-1018. doi: 10.1111/vco.12241. Epub 2016 May 3.
Cutaneous mast cell tumours (MCT) are the most common skin tumour in dogs, and to our knowledge, there are no previous studies regarding the global methylation of these tumours. DNA hypomethylation and hypermethylation have been described in several tumours and both mechanisms can lead to carcinogenesis. The purpose of this study was to evaluate the global DNA methylation in canine MCT. A total of 48 MCT samples were classified in grades 1, 2 and 3 or high-grade or low-grade. Monoclonal antibodies were used for the immunohistochemical detection of the 5-methylcytosine. The immunostained nuclei were classified in strong, weak or negative pattern, and these were quantified in five distinct microscopic fields (40× objective) in each slide. The results showed that global DNA hypomethylation was predominant in grade 3, high-grade, less differentiated MCT. These epigenetic changes in neoplastic mast cells warrant further detailed investigation aiming the establishment of tumour epigenetic therapies.
皮肤肥大细胞瘤（MCT）是犬类最常见的皮肤肿瘤，据我们所知，此前尚无关于这些肿瘤整体甲基化的研究。DNA低甲基化和高甲基化已在多种肿瘤中被描述，这两种机制均可导致癌症发生。本研究的目的是评估犬MCT中的整体DNA甲基化情况。总共48个MCT样本被分为1级、2级和3级或高级别或低级别。使用单克隆抗体对5-甲基胞嘧啶进行免疫组化检测。将免疫染色的细胞核分为强、弱或阴性模式，并在每张载玻片的五个不同显微镜视野（40倍物镜）中进行定量。结果表明，整体DNA低甲基化在3级、高级别、分化程度较低的MCT中占主导地位。肿瘤性肥大细胞中的这些表观遗传变化值得进一步详细研究，以期建立肿瘤表观遗传治疗方法。
