Genome-wide identification of cancer-specific alternative splicing in circRNA

Circular RNA (circRNA) is a group of RNA family generated by RNA circularization, which was discovered ubiquitously across different cancers. However, the internal structure of circRNA is hard to be determined since of the alternative splicing happened in exons and introns of circRNA and the cancer-specific alternative splicing of circRNA is less to be identified. Here we proposed a custom tool CircSplice, which could identify internal alternative splicing of circRNA and compare the differential splicing between samples. By applying CircSplice in ccRCC, we identified cancer-specific alternative splicing (AS) events belong to circRNAs in ccRCC. We further confirmed the existence of alternative splicing events in circRNAs by RT-PCR. This study is the first exploration of cancer-specific alternative splicing in circRNAs, which helps researchers to better understand potential functions of splicing of circRNAs in cancers. Circular RNAs profiles of three pairs of Clear Cell Renal cell carcinoma tissues and adjacent normal tissues were generated by RNA deep-sequencing, using HiSeq2500, Illumina.