Salivary miRNAs as a novel therapeutic marker in a patient with advanced oral squamous cell carcinoma: A case report

The global prevalence of oral squamous cell carcinoma (OSCC) has been increasing. OSCC at the advanced stage tends to resist conventional treatment and causes local recurrence and distant metastasis, resulting in poor prognosis. Therefore, detecting this cancer at an early stage and performing early intervention are important. Promising biomarkers to detect OSCC have yet to be established; however, microRNAs (miRNAs/miRs) serve a crucial role in OSCC tumorigenesis and may be potential biomarkers. In the present case report, the availability of salivary miRNAs as a therapeutic and prognostic marker for patients with OSCC was assessed. The patient was a 33-year-old woman who was diagnosed with advanced OSCC of the tongue, and their miRNA profile isolated from a saliva sample at each clinical course was evaluated. Microarray analysis of the salivary samples revealed changes in the levels of four miRNAs (hsa-miR-6798-5p, miR-6803-5p, miR-6805-5p and miR-6845-5p) in accordance with the clinical course. Neoadjuvant chemotherapy and surgical procedure decreased the levels, whereas the levels increased when the patient was diagnosed with lung metastasis. Furthermore, tongue and lung metastatic lesion specimens exhibited expression of the vascular endothelial growth factor receptor-2, which is regulated by the four miRNAs. Accordingly, the present report proposed that salivary miRNAs could be a therapeutic and prognostic biomarker for OSCC.