USP4 and head and neck squamous cell carcinoma: Since then, alterations in USP4 expression were found in several cancer entities (Li et al. 2016; Xing et al. 2016; Wang et al. 2020; Zhong et al. 2018; Yao et al. 2017) including an upregulation in HNSCC (Hou et al. 2013).