Fig. 4

The EV 3-mRNA signature is an independent prognostic biomarker for overall survival (OS) prediction of PDAC patients. A Box plots analysis showed the distribution of signature-associated risk score in PDAC patients from both training and validation cohorts categorized into subgroups of age (≤ 65 y = 46; > 65 = 75), gender (male = 60; female = 61), tumour stage (stage I–II = 113; stage III–IV = 59) and grading (G1–2 = 77; G3-4 = 69). Statistical differences were analyzed by Mann–Whitney U test after Shapiro–Wilk test. p < 0.05 is considered statistically significant. ns = not significant. B–D Kaplan–Meier analysis of OS of PDAC patients from both training and validation cohorts based on the risk scores of EV mRNA signature, tumour stage and combined EV mRNA signature and tumour stage. Hazard ratio (HR) and 95% confidence interval (CI) were generated from univariate Cox proportional hazard regression analysis. Statistical differences were analyzed with log-rank test. p < 0.05 is considered statistically significant. E The prognostic performance of serum CA19-9 in the combined training and validation cohorts of PDAC patients. The commonly routine used cut-off value of 37 units per milliliter (U/ml) was employed in this study. CA19-9: Carbohydrate antigen 19-9. Hazard ratio (HR) and 95% confidence interval (CI) were generated from univariate Cox proportional hazard regression analysis. Statistical differences were analyzed with log-rank test. p < 0.05 is considered statistically significant