Molecular and serologic markers of HPV 16 infection are associated with local recurrence in patients with oral cavity squamous cell carcinoma

Abstract

Human papillomavirus (HPV) infections predict mortality in Taiwanese patients with oral cavity squamous cell carcinoma (OCSCC). To address their prognostic significance for local recurrence (LR), in this retrospective cohort study we investigated different serologic and molecular markers of HPV 16 infection in 85 consecutive patients with primary OCSCC who received standard treatment and had their sera stored before treatment. Resected tumor specimens were examined with PCR-based assays for HPV 16 E6/E7 mRNA expression. Sera were tested with suspension arrays for the presence of HPV-specific antibodies using synthetic L1 and E6 peptides as well as a synthetic E7 protein. HPV 16 E6/E7 mRNA, anti-L1, anti-E6, and anti-E7 antibodies tested positive in 12%, 25%, 38%, and 41% of the study patients, respectively. Multivariate analysis identified pathological T3/T4, E6/E7 mRNA, and anti-E7 antibodies as independent risk factors for LR, whereas anti-E6 antibodies were an independent protective factor. In patients with ≥ 3 (high-risk group), 2 (intermediate-risk), and ≤ 1 (low-risk) independent risk factors (predictors), the 5-year LR rates were 75%, 42%, and 4%, respectively. Results were validated in an independent cohort. Together, our preliminary data indicate that HPV 16 infections as well as low and high serum levels of anti-E6 and anti-E7 antibodies, respectively, can serve as biomarkers of LR in patients with OCSCC, whereas the clinical usefulness of anti-HPV 16 antibodies for risk stratification of newly diagnosed cases deserves further scrutiny.

Keywords: human papillomavirus; local recurrence; mRNA expression; oral cavity squamous cell carcinoma; serology.

Figure 1. Local recurrence (LR) of 85 patients with oral cavity squamous cell carcinoma (OCSCC)

(A) Kaplan-Meier curves depicting the 5-year LR rates of patients with OCSCC (the discovery cohort) stratified according to human papilloma virus (HPV) 16 E6/E7 mRNA status. (B) Kaplan-Meier estimates of 5-year LR rates in different risk groups (the discovery cohort). (C) Kaplan-Meier estimates of 5-year LR rates in different risk groups (the validation cohort). *P < 0.05 (log-rank test).

Figure 2. Serologic antibody profiles against human papilloma virus (HPV) 16 antigens and risk stratification in terms of 5-year LR rates

(A, C, E) Plots representing the levels of anti-L1, E6, and E7 antibodies in 12 healthy controls, 75 HPV 16 E6/E7 mRNA-negative patients with oral cavity squamous cell carcinoma (OCSCC), and 10 HPV 16 E6/E7 mRNA-positive patients with OCSCC. The boundaries of the boxes indicate the interquartile ranges, whereas the lines in the boxes represent the medians. Whiskers indicate the maximal and minimal values. *P < 0.05 (Kruskal-Wallis test). (B, D, F) Kaplan-Meier curves depicting the 5-year LR rates of 85 patients with OCSCC stratified according to the optimal cutoffs of anti-L1, E6, and E7 antibodies. *P < 0.05 (log-rank test).

Figure 3. Flow of the patients through the study

HPV, human papillomavirus.