A panel of microRNA signature in serum for colorectal cancer diagnosis

Dysregulated expression of specific microRNAs (miRNAs) in serum has been recognised as promising diagnostic biomarkers for colorectal cancer (CRC). In the initial screening phase, a total of 32 differentially expressed miRNAs were selected by quantitative reverse transcription polymerase chain reaction (qRT-PCR) based Exiqon panel with 3 CRC pool samples and 1 normal control (NC) pool. Using qRT-PCR, selected serum miRNAs were further confirmed in training (30 CRC VS. 30 NCs) and testing stages (136 CRC VS. 90 NCs). We identified that serum levels of miR-19a-3p, miR-21-5p and miR-425-5p were significantly higher in patients with CRC than in NCs. The areas under the receiver operating characteristic (ROC) curve of the three-miRNA panel were 0.86, 0.74 and 0.87 for the training, testing and the external validation stages (30 CRC VS. 18 NCs), respectively. Significantly, elevated expression of the three miRNAs was also observed in CRC tissues (n = 24). Furthermore, the expression levels of the three miRNAs were significantly elevated in exosomes from CRC serum samples (n = 10). In conclusion, we identified a serum three-miRNA panel for the diagnosis of CRC.