Fig. 4

Survival analysis in human papillomavirus-positive (HPV+) and p16+ models. Kaplan–Meier survival curves for overall survival in (a, b) HPV+ and (c, d) p16+ models. In the HPV+ model, TNM stage was not associated with survival (a), whereas ERα expression was associated with prolonged survival (b). In the p16+ model, TNM stage and ERα expression were associated with prolonged survival (c, d); however, multivariate analysis revealed ERα expression as an independent prognostic factor (p = 0.037, hazard ratio: 0.109, 95% confidence interval 0.013–0.871)