HOPX plays a critical role in epithelial cell homeostasis and serves as a tumor suppressor in head and neck cancer (HNSCC), which is markedly down-regulated in three different subtypes of HNSCC, including tumors of the oral cavity (OSCC), oropharynx (OPSCC), and nasopharynx (NPC) [52]. Here, HOPX is linked to head and neck squamous cell carcinoma.