Chapter 3 - MicroRNA regulation of different subtypes of head and neck malignancies

Abstract

Head and neck cancer (HNC) is the seventh most frequent cancer worldwide. It is associated with high mortality and morbidity rates attributing for more than 660,000 new cases and 325,000 deaths annually. HNCs mainly localize in the oral cavity, larynx, sinonasal cavities, pharynx, and salivary glands, and approximately 90% of HNCs are squamous cell carcinoma. The incidence of HNC is expected to grow by 30% yearly by 2030 across both developed and developing countries. The five-year survival for HNC globally averages at 50% of cases and it has not improved much in the recent decades despite the advancements in multimodal therapy. This is due to pertaining challenges including tumor recurrence, treatment-resistance, late diagnosis, lack of efficient noninvasive screening methods, reducing chemo- and radio-therapy-related toxicity, increasing treatment specificity, and personalization of treatment. Thus, finding new diagnostic, prognostic, and predictive biomarkers and promising targets for treatment may improve the prognosis of HNC patients. MicroRNAs (miRNAs) exert a substantial effect on the growth and development of HNCs. Aberrant expression of miRNAs is involved in proliferation, radio-resistance, chemoresistance, epithelial-to-mesenchymal transition (EMT), and metastasis in HNCs. miRNAs are categorized broadly into oncogenic and tumor suppressor miRNAs. Different types of miRNA are differentially expressed in the HNC subtypes. The miRNA expression profile is also emerging among the best biomarkers for the diagnosis and treatment of HNC. Therefore, in this chapter, we discuss the role of miRNAs in different subtypes of HNC.