Analysis of circular RNA-associated competing endogenous RNA network in breast cancer

As the most common type of cancer in female patients, the morbidity and mortality rates of breast cancer (BC) are high, and its incidence is gradually increasing worldwide. However, the underlying molecular and genetic mechanisms involved in the etiopathogenesis of BC remain unclear. Circular RNAs (circRNAs) are a novel type of non-coding RNAs that have been verified to serve a crucial role in tumorigenesis. However, the majority of functions and mechanisms of circRNAs remain unknown. The present study identified 47 differentially expressed circRNAs in a dataset from Gene Expression Omnibus. Using the cancer-specific circRNA database, the potential microRNA (miRNA) response elements, RNA-binding proteins and open reading frames of the candidate circRNAs were predicted. Combing the predictions of miRNAs and target mRNAs, a competing endogenous RNA network was constructed, which may serve as the theoretical basis for further research. Furthermore, the analyses conducted using Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways indicated that candidate circRNAs may serve a role in transcriptional regulation. Moreover, 20 BC tissue specimens and their paired adjacent normal tissue specimens were used to evaluate the expression levels of the screened circRNAs. Thus, the analyses of the raw microarray data conducted in the present study offer perspectives on the exploration of mechanisms associated with BC tumorigenesis with regard to the circRNA-miRNA-mRNA network.