microRNA portraits in human vulvar carcinoma

Unregulated expression of microRNAs is well known and has already been demonstrated in many tumor types. However, in vulvar carcinoma this field has been unknown territory. Our study characterizes microRNA in vulvar tumors through an expression profile of 754 miRNAs, relating this with clinical and anatomopathologic data, and presence of HPV infection. Twenty HPV-negative and 20 HPV-positive samples, genotyped for high-risk HPVs (HPV16, 18, 31, 33) and a pool of seven normal vulvar skin samples were used for the identification of differentially expressed miRNAs by TLDA Quantitative Real Time PCR (qRT-PCR). Twenty-five differentially expressed microRNAs between HPV-positive and HPV-negative groups and 79 differentially expressed on the tumor compared with normal samples were obtained. A network between microRNA expression profiles and putative target mRNAs predicted by target prediction algorithms and previously demonstrated as relevant in vulvar carcinomas, such as TP53, RB, PTEN, and EGFR was constructed. Downregulation of both miR-223-5p and miR-19-b1-5p were correlated with the presence of lymph node metastasis; downregulation of miR-100-3p and miR-19-b1-5p were correlated with presence of vascular invasion; overexpression of miR-519b and miR-133a were associated with advanced FIGO staging. In conclusion, our study demonstrates that microRNAs may be clinically important in vulvar carcinomas and our findings may help for further studies on functional implications of miRNA deregulation in this type of cancer.