Department for Radiobiology and Molecular Genetics, Vinca Institute of Nuclear Sciences, University of Belgrade, Mike Alasa 12-14, Belgrade, 11000, Serbia.
Institute for Oncology and Radiology of Serbia, Pasterova 14, Belgrade, 11000, Serbia.
Mol Diagn Ther. 2017 Oct;21(5):511-523. doi: 10.1007/s40291-017-0285-9.
MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression, involved in the silencing of messenger RNA (mRNA) translation. The importance of miRNA signatures in disease screening, prognosis, and progression of different tumor types and subtypes is increasing. miRNA expression levels change depending on numerous factors. In this review, we are describing the circumstances under which miRNA levels can change, these are named 'levels' of heterogeneity of miRNAs. miRNAs can have oncogenic, tumor suppressive, or both roles depending on tumor type and target mRNA whose translation they silence. The expression levels of a single miRNA may vary across different cancer types and subtypes, indicating that a miRNA signature may be tissue specific. miRNA levels of expression also vary during disease formation and propagation, indicating the presence of a time profile for their expression. The complexity of the miRNA-mRNA interference network mirrors different genetic and epigenetic changes that influence miRNA and mRNA availability to each other, and hence, their binding ability. The potential role of miRNAs as biomarkers is two-fold; first, for monitoring of the phases of cancer pathogenesis, and second, to characterize the particular type/subtype of cancer. It is important that a particular miRNA should be characterized by examining as many types and subtypes of cancers as are available, as well as being extracted from different types of samples, in order to obtain a complete picture of its behavior and importance in the disease pathology.
微小 RNA（miRNAs）是基因表达的转录后调控因子，参与信使 RNA（mRNA）翻译的沉默。miRNA 特征在不同肿瘤类型和亚型的疾病筛查、预后和进展中的重要性日益增加。miRNA 的表达水平取决于许多因素。在这篇综述中，我们描述了 miRNA 水平可以改变的情况，这些情况被称为 miRNA 的“水平”异质性。miRNA 可以具有致癌或肿瘤抑制作用，也可以根据肿瘤类型和它们沉默的翻译靶 mRNA 而具有双重作用。单个 miRNA 的表达水平可能在不同的癌症类型和亚型中有所不同，表明 miRNA 特征可能具有组织特异性。miRNA 的表达水平也在疾病形成和传播过程中发生变化，表明其表达存在时间谱。miRNA-mRNA 干扰网络的复杂性反映了影响 miRNA 和 mRNA 相互可用性的不同遗传和表观遗传变化，因此也反映了它们的结合能力。miRNA 作为生物标志物的潜在作用有两个方面；首先，用于监测癌症发病机制的各个阶段，其次，用于表征特定类型/亚型的癌症。重要的是，应该通过检查尽可能多的癌症类型和亚型，以及从不同类型的样本中提取，来对特定的 miRNA 进行特征描述，以便获得其在疾病病理学中的行为和重要性的完整图景。
