Abstract 1566: Association of a serum HPV16 IgG signature and risk of oropharyngeal cancer

Abstract

Abstract Introduction: Human papillomavirus type 16 (HPV16) infection is associated with an increasing fraction of oropharyngeal cancer. The aim of our study was to determine the association of HPV16 antibodies (Abs) and oropharyngeal cancer (OPC) risk in sera obtained prior to clinical diagnosis. Methods: We identified 92 participants with incident oropharyngeal cancers and 460 age-, gender-, region- and year- matched controls from the Janus Serumbank in Norway. Serum samples were collected from cases, on average, 9.2 years before diagnosis (range, -0.6-14.9 years). 11 cases had serum samples from multiple time points. IgG Abs to the HPV16 antigens E1, E4, E5, E6, E7, L1, L2, and the N-terminal and C-terminal fragments of E2 (NE2, CE2) were quantified in blinded fashion using a custom RAPID ELISA assay. Full-length genes were expressed as GST fusion proteins with a mammalian protein expression system, incubated with sera, and bound IgG was measured. The ratio of relative luminescence units (RLU) values for each antigen to control GST protein was determined. Cutoff values were pre-established as 3 SD>median of 247 healthy controls. A logistic regression classifier of a 7-Ab biomarker panel (E1, NE2, CE2, E4, E5, E6, E7) for the predictive diagnosis of OPC was trained on an independent sample set, and applied to these samples. P-values were calculated by Fisher's exact test. Odds ratios (ORs) of cancer and 95% CIs were calculated. Results: HPV16 early antigen seropositivity was present in 13% of patients with OPC and 1% of controls (OR, 17.0; 95% CI, 5.0-74.0, p<0.0001). The probability of seropositivity was inversely associated with the time from serum collection and diagnosis (0-2 years, 84.9; >10 years, 5.4). Abs to CE2 were strongly associated with cases 0-2 years pre-diagnosis (OR, 112.0; 95% CI, 15.0-971.2, p<0.0001). Conclusion: HPV16 Abs to multiple early viral antigens are detectable years prior to diagnosis of oropharyngeal cancer, and the probability of seropositivity increases closer to diagnosis. A model for screening would help identify individuals at risk for whom interventions and surveillance may be evaluated. Citation Format: Karen S. Anderson, Hilde Langseth, Garrick Wallstrom, Marshall Posner, Julia N. Cheng, Rizwan Alam, Diego Chowell, Jon Mork. Association of a serum HPV16 IgG signature and risk of oropharyngeal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1566. doi:10.1158/1538-7445.AM2015-1566