Prognostic significance of high-risk human papillomavirus and p16INK4A in patients with esophageal squamous cell carcinoma

The prognostic value of the HPV status in ESCC is much controversial, this study aimed to determine the prognostic importance of high-risk HPV and p16 in patients with ESCC. A total of 105 consecutive patients who underwent esophagectomy in 2008 were included in this study. All specimens with ESCC were tested by in situ hybridization for HPV16/18 and immunohistochemistry for p16 expression. Kappa values were calculated using Cohen's kappa test. The 5-year overall survival (OS) and progression-free survival (PFS) were calculated in relation to the two markers and the Cox proportional hazards model was used to determine the hazard ratio (HR) of variables. Thirtynine (37.1%) of 105 were p16-positive, and HPV was detected in 29 of the 105 patients (27.6%) with ESCC. P16 was detected in 25 of the 29 patients (86.2%) who were HPV-positive, and only 14 of 76 patients (18.4%) who were HPV-negative (P < 0.001). Cohen's kappa coefficient revealed an agreement in two researchers (kappa = 0.61). The 5-year OS rate and PFS rate in the p16-positive group were 64.1% and 58.7%, respectively, and the rates in the p16negative group were 45.5%, 37.9%, respectively. The difference of survival rate between the two groups remained statistically significant. P16-positive patients had better 5-year rates of OS and PFS than p16-negative group (P = 0.02 and P = 0.007 by the Log-rank test, respectively). Using HPV status as a stratification factor, we found differences in OS and PFS that were consistent with those based on p16 expression. P16 is a very good marker of HPV infection for ESCC. HPV-positive or p16-positive ESCC is a distinct entity with a favorable prognosis compared with HPV-negative or p16-negative ESCC.