Circular RNA circ_0002138 is down-regulated and suppresses cell proliferation in colorectal cancer

Circular RNAs (circRNAs) have been recently identified as widespread and diverse endogenous noncoding RNAs that may harbor vital functions in humans. However, the role of circRNAs in the process of tumorigenesis and development of colorectal cancer (CRC) remains hitherto vague. In this study, we investigated the expression level of circ_0002138 in 35 paired CRC tissues by quantitative real-time polymerase chain reaction (qRT-PCR) and found that circ_0002138 was stably down-regulated in CRC tissues compared to paired adjacent normal tissues (P