In recent years, PC has been a therapeutic challenge due to difficulties and delays in diagnosis, which leads to its poor prognosis. Up to now, the main treatment methods for PC are surgical operation, chemotherapy and radiotherapy. Nevertheless, The median survival time of PC is about 5 to 8 months, and the 5-year survival rate is only about 4%. 5 In this study, we explored the early diagnostic value of plasma miR-181b, miR-196a and miR-210 in PC patients and found that combined detection of plasma miR-181b, miR-196a and miR-210 has early diagnostic value for PC.
Accumulating evidence has reported that a variety of miRNAs could play important roles in PC. 13-16 For example, miR‑381, a tumor suppressor, inhibits cell proliferation, migration and invasion, and induces apoptosis in PC. 17 Zhou et al. have reported that miR-340 is downregulated in PC and could suppress PC cell growth and reduce tumor size. 18 Xu et al. 19 have indicated that miR-143 is lowly expressed in PC and could regulate PC process by promoting PC cell apoptosis and inhibiting migration and invasion. In addition, Xu et al. 19 have also confirmed that miR-143 expression is closely associated with the tumor size, clinical staging and lymph nodes metastasis. Previous researches have indicated that the expressions of miR-196a and miR-210 are upregulated in the plasma of PC patients, indicating miR-196a and miR-210 could serve as potential biomarker for PC diagnosis. 20 Ren et al. 12 have reported that fecal miR-181b, miR-196a and miR-210 are highly expressed in PC patients, suggesting that those miRNAs may be used as biomarkers for PC diagnosis. In the present study, we found that the expressions of miR-181b, miR-196a and miR-210 were closely associated with lymph nodes metastasis, clinical stage and vascular invasion, but had no correlation with the patient's age, gender and tumor size. Therefore, we speculate that the combinations of miR-181b, miR-196a and miR-210 may be used as biomarkers for PC diagnosis.
Recently, some diagnostic biomarkers such as CA199, CA242, MIC-1 and Lectins can be detected in the plasma of PC patients and have been accessed for PC diagnosis. 21-24 However, CA199 is the best available biomarker among the diagnostic biomarkers. 21,25,26 In the present study, the level of CA199 was significantly upregulated in the plasma of PC patients. Up to now, more and more studies have indicated that the combination of plasma miRNAs with CA199 is effective for diagnosis and can distinguish PC. 21,27 However, CA199 is not a reasonable marker for early diagnosis of PC. Thus, it is important to explore the more effective diagnostic biomarkers for PC. In this study, we demonstrated that the expressions of miR-181b, miR-196a and miR-210 were significantly upregulated in PC patients. In addition, the results of the receiver operating characteristic (ROC) curve showed that miR-181b, miR-196a and miR-210 have lower AUC than CA199 in PC. The combinations miR-181b + miR-196a, miR-181b + miR-210, miR-196a + miR-210 also have lower AUC than CA199 in PC. It is worth noting that the combinations miR-181b + miR-196a + miR-210 have higher AUC than CA199 in PC. Moreover, miR-181b + miR-196a + miR-210 significantly improved the value of each indicator in individual diagnosis.