MiR-199a and miR-125b expression levels in serum of women affected by epithelial ovarian cancer

Recent studies show that microRNA (miRNAs) are involved in cancer by regulating cell proliferation, apoptosis and angiogenesis. Accordingly, their deregulation could contribute to cancer development and progression. It has been demonstrated that in ovarian tissue the over-expression of miR-199a and miR-125b inhibits tumor angiogenesis, a fundamental process for cancer development and growth. Aims of our study were to investigate the expression levels of miR-199a and miR-125b in serum of patients with ovarian cancer (OC) and to evaluate the correlation between miRNAs expression and traditional biomarkers [CA125 and human epididymis protein 4 (HE4)]. 32 patients with epithelial OC (54±14 years old) and 31 healthy controls (55±17 years old) were enrolled. Serum samples were collected prior to definitive surgical treatment and RNA extraction was performed by using the miRNeasy Serum/Plasma kit (Qiagen GmbH). miR-199a and miR-125b expression was determined by quantitative real timepolymerase chain reaction (TaqMan MicroRNA Assay, Applied Biosystems). The expression levels of miRNAs were normalized to miR-16 and calculated utilizing the 2-ΔCt method. Serum levels of miR-199a and miR-125b were significantly higher in OC patients compared to controls (P=0.007 and P=0.002, respectively). A marginally statistically significant correlation was found between miR-199a and miR-125b expression levels (r=0.38, P=0.03). The ROC curve analysis of the diagnostic performance between healthy controls and OC patients revealed that HE4 had a significantly higher area under the curve (AUC=0.90) when compared to CA125 (AUC=0.85), miR-199a (AUC=0.70) and miR-125b (AUC=0.67). Anyway, the determination of circulating miRNAs may be relevant, since their expression is known to be aberrant in cancer, having potential ability to monitor tumor dynamics.