Identification of axillary lymph node metastasis-related circRNAs in breast cancer using transcriptome sequencing

Circular RNAs (circRNAs) play critical roles in the initiation and progression of cancer. Emerging evidence shows that circRNAs may function as potential markers for cancer diagnosis and treatment. However, the roles of circRNAs in breast cancer axillary lymph node metastasis (ALNM) remain need to be determined. Transcriptome sequencing was performed to screen the differentially expressed circRNAs in three breast cancer tissues with ALNM and three without ALNM. Overall design: For transcriptome sequencing, breast cancer tissues were collected from six patients, including three with axillary lymph node metastasis (ALNM) and three without ALNM. Transcriptome high-throughput sequencing was performed. Raw junction reads for all samples were normalized by total reads number and log2 transformed. Differentially expressed circRNAs were identified between two groups (P < 0.05, fold change > 2). Totally, 31 circRNAs were found to be differentially expressed in breast cancer with ALNM versus without ALNM (fold change > 2, P < 0.05). Among the 31 circRNAs, 21 were upregulated and 10 were downregulated in breast cancer with ALNM compared with those without ALNM.