POU5F1 and head and neck squamous cell carcinoma: To further analyze the impact of Oct4 deregulation on HNSCC radioresistance, we generated Cal33-tdTomato and Cal33-Oct4-HA-tdTomato cell lines by stable transfection of Cal33 cells with pWPXL-tdTomato and pWPXL-Oct4-HA-tdTomato plasmids.