OBJECTIVEThe aim of this study was to identify six miRNAs expressed in plasma of patients with pancreatic cancer (PCa) and analyze their value as a diagnostic index of pancreatic cancer.

METHODSPlasma total RNAs were extracted from 30 PCa patients and 26 normal controls, and the abundance of six microRNAs was measured using real-time PCR. The possibility to combine them with CA19-9 as diagnostic biomarkers was analyzed.

RESULTSThe expression level of miR-21, miR-210, miR-155, miR-20a, miR-25 and miR-196a in plasma of patients with pancreatic cancer were 1.65×10(6), 5.98×10(4), 2.83×10(3), 3.47×10(6), 2.76×10(6), and 1.03×10(3) (copies/µl), while the normal controls were 4.08×10(5), 2.54×10(4), 8.55×10(2), 1.79×10(6), 9.32×10(5), and 4.67×10(2) (copies/µl), respectively, with a significant difference between the two groups (P < 0.05). The areas under the ROC curve of miR-21, miR-210, miR-155, miR-20a, miR-25 and miR-196a were 0.893, 0.810, 0.820, 0.766, 0.816 and 0.729, respectively. MiR-21 had the highest diagnostic value when it was used as diagnostic marker alone. The combination of miR-155 and miR-25 was more effective to distinguish PCa from normal than to be used alone, and the area under the ROC curve was 0.913 (95%CI 0.838-0.988) .When CA199 associated with miR -210 and miR-25, respectively, the areas under the ROC curves were 0.96 (95%CI was 0-1.0) and 0.942 (95% CI was 0.876-1.0), which were higher than CA199 alone (0.862, 95%CI was 0.748-0.975). There was a high improvement in diagnostic sensitivity and accuracy when miR-210 and miR-25 were combined with CA19-9, respectively.

CONCLUSIONSPlasma miR-21, miR-155, miR-25, miR-210 have diagnostic value for pancreatic cancer, and deserve further study.