Circulating miR-15b, miR-34a and miR-218 as promising novel early low-invasive biomarkers of cervical carcinogenesis.

INTRODUCTION Circulating biological markers, such as miRNAs, hold the greatest possibilities to complement tissue biopsy and clinical diagnostic tests. The objective of this study was to evaluate the relative abundance of three circulating miRNAs in serum from 17 HPV16-positive patients with early cervical lesions known as Low Grade Squamous Intraepithelial Lesions (LSILs). METHODS The expression of circulating microRNAs miR-15b, miR-34a and miR-218, in patients with LSILs was compared to 23 HPV-negative individuals showing normal cervical epithelium (healthy women) and 23 Squamous Cell Carcinoma (SCC) samples. RESULTS The expression levels of miR-15b remained unchanged while those of miRNAs 34a and 218 were relatively high in serum obtained from LSIL patients in comparison with healthy women (results were statistically significant with a p of <0.01 or <0.001). According to previous findings, miR-15b was overexpressed and miRNAs 34a and 218 were underexpressed in serum from SCC patients. Additionally, the mRNA expression levels of some selected gene targets were determined [Cyclin D1 (CCND1), Cyclin E1 (CCNE1), B-cell lymphoma 2 (Bcl-2) and MutS homolog 2 (MSH-2)]. All serum results correlated with tissue samples from the same patients. CONCLUSION We propose that circulating microRNAs can be valuable as molecular markers for the early follow up of cervical carcinogenesis risk.