Risk factors and survival by HPV-16 E6 and E7 antibody status in human papillomavirus positive head and neck cancer.

High-risk human papillomavirus types (HPV-HR) are associated with head and neck cancer (HNC) risk and better survival. Most patients with HPV-HR DNA-positive tumors develop anti-HPV E6/E7 antibodies; however, it is unclear whether those who mount an immune response have similar risk factors or clinical outcomes as those who do not. HPV-16 DNA tumor-positive HNC cases were evaluated for HPV-16 E6 and E7 antibodies using a GST capture ELISA system. Among 57 HPV-16 DNA tumor-positive HNC cases, 67% were detected with HPV-16 E6 and/or E7 antibodies. Male gender (76% vs. 42%, p = 0.02), younger age (63% vs. 16%, p = 0.001) but not tobacco or alcohol were associated with E6 and/or E7 seropositivity. Seropositivity was associated more often with late stage (76%), poor grade (65%), positive nodes (82%). and in the oropharynx (82%), Median disease-specific and recurrence-free survival were longer in E6 and/or E7 seropositive compared to E6/E7-negative cases (2.2 years vs. 1.4 years, both outcomes), although results were not statistically significant. When examined jointly with p16 expression, E6 and/or E7-positive/p16-positive cases had better disease-specific (2.1 years vs. 1.1 years, p = 0.06) and recurrence-free (2.3 years vs. 1.1 years, p = 0.03) survival compared to E6-/E7-/p16- cases. These findings suggest there are 2 distinct HNC patient groups with HPV DNA-positive tumors, distinguishable by E6 and/or E7 antibody status. Differences in antibody status are associated with distinct risk factors and clinical outcomes. This information can be available as a simple blood test at initial presentation, before the removal of tissue through biopsy or surgery.