Identification of Neck Lymph Node Metastasis-Specific microRNA—Implication for Use in Monitoring or Prediction of Neck Lymph Node Metastasis

SIMPLE SUMMARY: There are no established biomarkers for oral squamous cell carcinoma (OSCC), and detection of neck lymph node metastases relies on imaging studies. Diagnosis and prediction using biomarkers, which are less invasive and simpler than imaging tests, could improve prognosis if lymph node metastases could be treated earlier. In this study, serum microRNAs were successfully used to diagnose primary neck lymph node metastases and predict late neck lymph node metastases. They reflected the presence of lymph node metastasis more accurately than serum squamous cell carcinoma antigens or pathological factors. ABSTRACT: MicroRNAs (miRNAs) have attracted attention as non-invasive cancer biomarkers in various cancers; however, they have not been adequately investigated in oral squamous cell carcinoma (OSCC). This study investigated the diagnostic performance of serum-derived miRNAs at initial diagnosis for primary neck lymph node metastasis and the predictive performance for late neck lymph node metastasis based on long-term (up to approximately 8 years) follow-up of patients with OSCC. The expression of miRNAs in 40 patients with OSCC was quantified using real-time PCR (qPCR), and a comprehensive statistical analysis of the correlation of miRNA expression for primary and late neck lymph node metastases was performed. For the diagnosis of primary neck lymph node metastases, miR-423 and miR-125 were accurate. The miRNA index for primary metastasis diagnosis (miR-PM) calculated by regression analysis showed high diagnostic accuracy. The miR-5100 was useful for predicting late neck lymph node metastases. The miRNA index for late metastasis prediction (miR-LM) calculated using regression analysis showed high prediction accuracy. MiRNAs were useful for diagnosing primary neck lymph node metastases in OSCC and predicting late neck lymph node metastases. It may help to consider individualized treatment, including follow-up, surgical methods, and postoperative management.