PDCD4 and head and neck squamous cell carcinoma: Downregulation of HNSCC cells with Nanog/Stat-3 and/or miR-21 by treating cells with Nanog/Stat-3-specific siRNAs or anti-miR-21 inhibitor effectively blocks HA-mediated Nanog-Stat-3 signaling events, abrogates miR-21 expression and increases PDCD4 expression.