Figure 5: Cumulative prognostic value of stage IVA patients (Kaplan-Meier analysis). (a) p16 positive patients showed better prognosis (). (b) No difference was observed between IFI16 positive and negative patients (). (c and d) p16 negative patients exhibited worse prognosis in IFI16 positive ((c) ) group. No significant difference was observed in IFI16 negative ((d) ) group. Statistical analysis was performed using the log-rank test.