CDKN1A and head and neck squamous cell carcinoma: The following observations argue that gain- and loss-of-function of miR301a-3p alters p21 levels by relieving miRNA-mediated translational control of p21. First, to investigate whether miR301a-3p targets and alters p21 levels in vivo, we transfected HNSCC cells UMSCC74B (Fig 5B), UMSCC74A (S5A Fig), and LSCC A549 (S5G Fig) with anti-miR301a-3p.