Potential Oncogenic Role and Prognostic Implication of MicroRNA-155-5p in Oral Squamous Cell Carcinoma

Altered microRNA expression is associated with cancer progression. This study investigated the prognostic significance of microRNA-155-5p (miR-155-5p), a well-known oncomiR, in oral squamous cell carcinoma (OSCC). miR-155-5p expression was assessed using quantitative reverse-transcription polymerase chain reaction in 68 formalin-fixed, paraffin-embedded OSCC specimens. E-Cadherin immunohistochemistry was conducted to correlate epithelial-mesenchymal transition (EMT) with miR-155-5p expression. Elevated miR-155-5p was associated with higher pathological TNM stage (p=0.048) and relapse (p=0.029). High miR-155-5p expression, along with angiolymphatic invasion and advanced stage, was a statistically significant prognostic factor for poorer disease-free survival. In patients with stage I-II disease, high miR-155-5p was the only significant prognostic factor (p=0.033). A significant negative correlation was observed between miR-155-5p and E-cadherin expression (p=0.015), suggesting a possible role for miR-155-5p in EMT. miR-155-5p expression might contribute to EMT-associated OSCC progression and serve as a biomarker for predicting relapse, especially for patients with early-stage OSCC.