Expression of selected MicroRNAs in pancreatic ductal adenocarcinoma in relation to tumor progression and patient’s outcome.

Background: pancreatic ductal adenocarcinoma (PDAC) remains a disease with extremely poor prognosis and limited effective available treatment. Differential expression of miRNAs isolated from tumor tissue has been proposed as a marker for tumor diagnosis, progression and prognosis. Nevertheless, prognostic value of miRNAs expression in PDACs for patient outcome still remains unclear.Methods: expression of 7 selected miRNAs, isolated from FFPE samples of 54 PDAC patients, was quantified using RT-qPCR. The relationship of miRNA expression levels with tumor histology, clinico-pathological characteristics, patient overall survival (OS) and progress-free survival (PFS), was subsequently evaluated.Results: overexpression of miR-21, miR-155 and miR-210 was observed in PDACs (up to 72.62-fold, 232.36 and 181.38-fold respectively), in comparison with non-neoplastic tissues. On the other hand, miR-96 and miR-217 were significantly downregulated in PDACs (up to one hundred times). No differences were, however, noticed between cancer and normal tissues for the expression levels of miR-148a and miR-196a.On the other hand, expression levels of all 7 miRNAs failed to demonstrate significant correlation with parameters of tumor progression, such as tumor stage, grade, nodal involvement, perineural and vascular invasion. Positive correlation of miR-210 levels was, however, observed with patient age (ρ=0.35). Additionally, miR-148a and miR-217 expression have shown positive association with tubular tumor growth pattern (ρ=0.39; ρ=0.28). Negative correlation of miR-148a values was also demonstrated with dissociative growth pattern and nuclear atypia (ρ=-0.30; ρ=0.27).