Transcriptome profiling identifies a recurrent CRYL1-IFT88 chimeric transcript in hepatocellular carcinoma

We performed transcriptome sequencing for hepatocellular carcinoma (HCC) and adjacent non-tumorous tissues to investigate the molecular basis of HCC. Nine HCC patients were recruited and differentially expressed genes (DEGs) were identified. Candidate fusion transcripts were also identified. A total of 1943 DEGs were detected, including 690 up-regulated and 1253 down-regulated genes, and enriched in ten pathways including cell cycle, DNA replication, p53, complement and coagulation cascades, etc. Seven candidate fusion genes were detected and CRYL1-IFT88 was successfully validated in the discovery sequencing sample and another 5 tumor samples with the recurrent rate of about 9.52% (6/63). The full length of CRYL1-IFT88 was obtained by 3' and 5' RACE. The function of the fusion transcript is closed to CRYL1 because it contained most of domain of CRYL1. According to the bioinformatics analysis, IFT88, reported as a tumor suppressor, might be seriously depressed in the tumor cell with this fusion because the transcript structure of IFT88 was totally changed. The function depression of IFT88 caused by gene fusion CRYL1-IFT88 might be associated with tumorigenesis or development of HCC.