Human microRNA 184 (miR-184) is overexpressed in squamous cell carcinoma (SCC) of the tongue. In vitro inhibition of miR-184 levels could induce apoptosis and hinder proliferation of tongue SCC cells. Patients with tongue SCC have high plasma miR-184 levels. Plasma miR-184 is likely associated with the tumor load. Surgical removal of the primary tumor reduced plasma miR-184 levels significantly. The data suggested that miR-184 is linked to the pathogenesis of tongue SCC. Further studies are warranted to evaluate the use of microRNA-based serological markers in monitoring tongue SCC.