Identification of serum miR-30a-5p as a diagnostic and prognostic biomarker in colorectal cancer

Circulating microRNAs (miRNAs) have become increasingly appreciated in the diagnosis and prognosis of colorectal cancer (CRC). The aim of this study was to assess the potential diagnostic and prognostic significance of serum miR-30a-5p as a potential biomarker. The expression levels of serum miR-30a-5p were measured in 138 cases with CRC, 50 cases with benign lesions (colorectal adenoma and polyps) and 60 healthy volunteers by quantitative real time polymerase chain reaction (qRT-PCR). The results showed that serum miR-30a-5p levels were frequently downregulated in patients with CRC and benign lesions in comparison with normal controls. Moreover, serum miR-30a-5p levels in early-stage CRC patients were significantly increased after surgery. Receiver-operating characteristic (ROC) curve analysis demonstrated serum miR-30a-5p could well distinguish CRC patients, early-stage CRC patients from healthy controls with a relative high value of area under the curve (AUC). Furthermore, low serum miR-30a-5p expression was more frequently occurred in CRC patients with aggressive clinical variables. Additionally, CRC patients exhibiting high serum miR-30a-5p expression had significantly prolonged overall survival than those exhibiting low expression. Finally, both univariate and multivariate analyses revealed that serum miR-30a-5p expression was an independent prognostic factor for overall survival in CRC patients. Collectively, these findings suggested serum miR-30a-5p might act as a novel biomarker for the diagnosis and prognosis of CRC.