Expression and clinical significance of plasma small RNA in patients with pancreatic cancer

Abstract

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