miRNA并不是一条单一的序列，而是由一簇具有序列多样性的isomiRs所组成。近年来，isomiR研究逐渐受到重视，被认为是非编码RNA调控的一个重要环节。本课题基于前期研究基础，拟开展以下工作：①通过公共小RNA测序资源的生物信息学分析探讨isomiR的生物学特点，②利用sRNA和mRNA测序技术，结合乳腺癌和宫颈癌揭示isomiR在肿瘤中的分布和表达模式，③初筛并验证肿瘤相关isomiRs，选取关键isomiRs开展功能研究，旨在阐明：miRNA加工和修饰过程所产生的isomiR谱是否具有细胞、组织、物种及疾病特异性？isomiR具有怎样的生物学功能并参与肿瘤的发生发展过程？结合isomiR的生物学特点和功能，发展一套从isomiR角度研究miRNA的分析方法和策略。本研究的实施将有助于加深对miRNA生物合成和调控模式的理解，丰富miRNA研究思路，具有一定的科学意义和指导意义。

miRNA is not a single sequence, but a series of isomiRs with sequence diversity. In recent years, isomiR has been gradually concerned as a pivotal link in non-coding RNA (ncRNA) regulatory network. Based on the current research, this project will: ① explore biological characteristics of isomiRs through bioinformatic analysis using public small RNA （sRNA） sequencing datasets; ② reveal isomiR profiles in breast and cervical cancer by applying sRNA and mRNA sequencing techniques; ③ select and validate cancer-associated isomiRs, and further screen crucial isomiRs to study biological functions. The aim is to elucidate: whether isomiR spectrums and expression patterns have cell, tissue, species specificity and disease-specific profiles through miRNA processing and modification process? What biological functions has isomiR? Whether isomiR contributes to occurrence and development of cancer? According to biological characteristics and functions of isomiR, we will develop analytical method and strategy to study miRNA at the isomiR levels. The project will contribute to further reveal miRNA biogenesis and regulatory patterns, and enrich the research ideas of miRNA. It therefore has important scientific and practical significance.