Increased miR-20b Level in High Grade Cervical Intraepithelial Neoplasia

Cervical cancer is a common malignant tumor worldwide ranking fourth in incidence and mortality among females, which was reduced significantly by cytology screening and human papilloma virus (HPV) DNA testing. The specificity of cytology is high; however, the sensitivity is low, in contrast to the HPV DNA testing. Despite the success of these measures, new biomarkers are still considered to aim increasing sensitivity and specificity of screening and diagnosis. Significant alterations in microRNA (miRNA) expression have been detected in several cancers with variable consistency. To investigate the stratification role of miRNAs between normal epithelium and cervical intraepithelial neoplasia (CIN2-3), we screened the expression of 667 miRNAs to identify significant markers (n = 10), out of them 9 miRNAs were applied in the study (miR-20b, -24, -26a, -29b, -99a, -100, -147, -212, -515-3p) along with RNU48 and U6 as the references. To benchmark the miRNAs, 22 paired (tumor-free and tumor tissue pairs) laser microdissection-obtained cervical formalin fixed, paraffin embedded tissue samples were assayed. The expression of miR-20b was 2.4 times higher in CIN2-3 samples as compared to normal tissues (p < 0.0001). In the HPV16-positive subsets of the samples (n = 13), miR-20b showed 2.9-times elevation (p < 0.001), whereas miR-515 was 1.15-times downregulated (p < 0.05) in CIN2-3 as compared to normal tissue. These results suggest the potential value of miR-20b as a statification biomarker in order to differentiate neoplastic and non-tumorous cases.