UCHL5 and head and neck squamous cell carcinoma: Compared to human oral keratinocytes (HOKs), USP14 was expressed at higher levels in HNSCC cells, with no obvious difference between HPV + and HPV- HNSCC cells (Fig. 2A) In contrast to the data in Fig. 1, UCHL5 was also expressed at high levels when compared to HOKs.