POU5F1 and head and neck squamous cell carcinoma: Moreover results above indicate that CIP2A expression correlates with tumor aggressiveness in vivo. To further test how CIP2A and Oct4 expression in HNSCC cells correlate with their tumorigenic capacity, we selected for subcutaneous xenograft experiment UT-SCC cell lines that contained either lower (UT-SCC-50) or higher (UT-SCC-14) CIP2A mRNA expression levels than in cell lines UT-SCC-9 and UT-SCC-7 whose CIP2A-dependence has been validated.