MicroRNAs are small non-coding RNA molecules with roles in gene expression regulation and implications in cancer initiation and progression. Cell-free microRNAs detected in body fluids, and in particular in plasma, are of clinical interest due to their possible use as biomarkers. Despite the fact that their reliable quantification depends on several technical parameters, there is great clinical interest in this approach due to its simplicity and low risk to the patient. Squamous cell carcinoma of the head and neck is one of the most common cancer types worldwide, with survival rates of about 50% in 5 years. Tobacco and alcohol consumption are the most important risk factors and, currently, the presence of cervical lymph node metastases remain the strongest prognostic factor for this cancer type. In this study we identified plasma microRNAs associated with squamous cell carcinomas of the oral cavity and oropharynx as well as with the presence of cervical lymph node metastases. We evaluated the expression of 179 microRNAs in plasma from 45 patients (28 presenting cervical lymph node metastases at diagnosis and 17 with no lymph node metastasis) and 15 healthy controls. Samples were matched according to age, sex, drinking and smoking habits. Among microRNAs mostly expressed in tumor samples, some had been already detected in oral squamous cell carcinoma tissues, such as miR-210, while others, such as miR-573, are still poorly studied. Comparisons between oral and oropharyngeal carcinomas yielded several differences, in accordance with molecular distinctions between these cancer types. MicroRNAs possibly involved in the metastatic process were identified when comparing plasma samples from individuals presenting lymph node metastasis at diagnosis and plasma from patients who were metastasis-free. Among these molecules, miR-192 and miR-574 were identified as more expressed in plasma from individuals with metastatic oropharyngeal cancer. We conclude that plasma microRNAs associated with specific clinical conditions or cancer sub-sites may help in the diagnosis and prognosis assessment of head and neck squamous cell carcinomas.

Citation Format: Flavia Maziero Andreghetto, Mariana Barbosa de Souza, Raquel Ajub Moyses, Tatiana Natasha Toporcov, Fabio Daumas Nunes, Marcos Brasilino de Carvalho, Patricia Severino. Circulating microRNAs as metastasis biomarkers in oral cavity and oropharyngeal squamous cell carcinomas. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1087.