Intestinal T‐cell lymphomas are common in dogs, but histopathological diagnosis remains challenging because of accompanying enteritis with lymphocyte involvement. Invasively taken full‐layer biopsies are still required for reliable differentiation. The detection of specific microRNA expression patterns in canine intestinal T‐cell lymphoma could provide new possibilities to differ intestinal lymphoma from benign inflammation and could lead to further understanding of lymphomagenesis. The objective of this study was to characterize microRNA expression in distinct groups of formalin‐fixed and paraffin‐embedded samples from canine intestinal T‐cell lymphomas, lymphoplasmacellular enteritis and healthy intestinal tissue. In a preliminary test with two samples per group, total RNA was extracted (RNEasy FFPE Kit, Qiagen), reverse transcribed (miScript II RT Kit, Qiagen) and pre‐amplified (miScript PreAmp PCR Kit, Qiagen). We performed comparative quantitative PCR on microRNA PCR Array plates (Qiagen) with pre‐fabricated reactions for 183 different mature canine microRNAs. Subsequently, 12 microRNAs with conspicuous expression changes in the lymphoma group were selected and microRNA expression of all samples (n = 8) per group was analysed with individual microRNA assays (miScript Primer Assays, Qiagen) on the reverse transcribed RNA without pre‐amplification. Our results revealed lymphoma‐specific expression patterns, with down‐regulation of the tumour‐suppressing microRNAs miR‐194, miR‐192, miR‐141 and miR‐203, and up‐regulation of oncogenic microRNAs, including microRNAs from the miR‐106a~363 cluster. In addition, we detected only slight expression alterations between healthy intestinal tissue and lymphoplasmacellular enteritis cases. We conclude that microRNA expression patterns can be used to separate T‐cell lymphomas from healthy tissue and benign inflammatory disorders.

中文翻译：

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犬肠道 T 细胞淋巴瘤中的肿瘤特异性 microRNA 表达模式。

肠道 T 细胞淋巴瘤在犬中很常见，但由于伴有淋巴细胞受累的肠炎，组织病理学诊断仍然具有挑战性。可靠的区分仍需要侵入性全层活检。检测犬肠道 T 细胞淋巴瘤中特定的 microRNA 表达模式可以为区分肠道淋巴瘤与良性炎症提供新的可能性，并有助于进一步了解淋巴瘤的发生。本研究的目的是表征来自犬肠道 T 细胞淋巴瘤、淋巴浆细胞性肠炎和健康肠道组织的福尔马林固定和石蜡包埋样品的不同组中的 microRNA 表达。在每组两个样本的初步测试中，提取总 RNA（RNEasy FFPE Kit，Qiagen），逆转录（miScript II RT Kit，Qiagen）和预扩增（miScript PreAmp PCR Kit，Qiagen）。我们在 microRNA PCR Array 板 (Qiagen) 上对 183 种不同的成熟犬 microRNA 进行了预制反应的比较定量 PCR。随后，选择了淋巴瘤组中具有显着表达变化的 12 个 microRNA，并使用单独的 microRNA 分析（miScript Primer Assays，Qiagen）对未经预扩增的逆转录 RNA 分析了每组所有样本（n = 8）的 microRNA 表达。我们的结果揭示了淋巴瘤特异性表达模式，下调了抑制肿瘤的 microRNAs miR-194、miR-192、miR-141 和 miR-203，上调了致癌 microRNAs，包括来自 miR-106a 的 microRNAs ~363 集群。此外，我们仅检测到健康肠组织和淋巴浆细胞性肠炎病例之间的轻微表达改变。我们得出结论，microRNA 表达模式可用于将 T 细胞淋巴瘤与健康组织和良性炎症疾病分开。