RNA sequencing identifies dysregulated circular RNAs in early-stage breast cancer

BackgroundBreast cancer is a major cause of cancer related death in women worldwide. Molecular diagnostic markers that are detectable in early-stage breast cancer can aid in effective clinical intervention. Circular RNAs are a recently identified group of non-coding RNA with potential role in cancer development and progression. In this study, we aimed to identify circular RNAs specific for early stage breast cancer.\n\nMethodCircular RNA expression profile was analyzed in early-stage breast cancer tissues (N=5), matched normal counterparts (N=5) and absolute normal samples (N=5) by RNA-sequencing that enables a comprehensive analysis of RNA expression across the transcriptome. Two different algorithms, find_circ and DCC were used to identify the differentially expressed circular RNAs.\n\nResultsA total of 58 and 87 circular RNAs were found to be differentially expressed by find_circ and DCC algorithms, respectively, among which 26 circular RNAs were common. Hsa_circ_0001946 (CDR1-as) was found to be upregulated in early stage breast cancer along with other novel circular RNAs (hsa_circ_0008225, hsa_circ_0007766, hsa_circ_0016601). We also found that a few of the identified circular RNAs harbor microRNA binding sites which can lead to microRNA sponging activity and pre-microRNA sequences which can generate mature microRNAs. The identified circular RNAs that are differentially regulated in early stage breast cancer can be of potential diagnostic/prognostic importance.\n\nConclusionCircular RNA are differentially expressed in the early-stage breast cancer with potential application in early diagnosis and prognosis. The differentially expressed circular RNA can sequester microRNA and can act as microRNA precursor as well.