E2F5 and head and neck squamous cell carcinoma: In addition, high E2F4 expression could lead to poor prognosis in HNSCC in both males and females, high expressions of E2F5, E2F6, and E2F7 were associated with poor OS of female HNSCC patients, while high E2F2 and E2F8 expressions were positively correlated with the OS of male HNSCC patients.