Reduction of circular RNA expression associated with human retinoblastoma

This study investigated the profile of circular RNA (circRNA) expression and its epigenetic role associated with human retinoblastoma (RB). Twelve paired primary samples from un-treated RB patients (primary RB samples and corresponding adjacent normal retinal samples) and eight recurrent RB samples from RB patients having recurrence after treatment were collected. Ribosomal-RNA depleted sequencing was performed in four paired primary samples. Quantitative polymerase chain reaction was conducted to validate circRNA and mRNA expression in the other eight paired primary samples and in eight recurrent RB samples. Bioinformatic analysis was applied to predict the oncological signal pathways and the binding microRNA (miRNA) of circRNA. As a result, a total of 47640 circRNAs were identified by RNA-sequencing, with a lower abundance of circRNAs in primary RB samples relative to matched normal retinal samples [22366 (47%) versus 37161 (78%), P