EZH2 and head and neck squamous cell carcinoma: The intratumoral expression of the major tumor suppressor protein p53 detected via immunohistochemistry was reported to affect the prognosis of HNSCC patients (Wang et al. [22]); furthermore, it might inhibit the actions of EZH2 through promoting the maintenance of the pRB-mediated inhibition of E2F, hence the decreased expression and activity of PRC2 members (Kulaberoglu et al. [17]), and possibly also in a more direct way by inhibiting EZH2 expression through repressing the EZH2 gene promoter (Tang et al. [23]).