PROJECT SUMMARY / ABSTRACT Background: Human papillomavirus (HPV)-related oropharyngeal cancer (OPC) is the most common HPV- related cancer in the U.S. While vaccinations against HPV are available, they will not substantially reduce incidence until 2060. In the absence of screening programs, patients typically present with advanced disease requiring treatment with lifelong consequences and early mortality. Two blood-based biomarkers, serum antibodies to HPV16 early (E) oncoproteins (HPV16 E Abs) and circulating tumor-modified HPV DNA (ctmHPVDNA), are highly sensitive and specific. Persistent oncogenic HPV at anogenital sites is a biomarker of anal and cervical cancer risk, though limited data exists on oral oncogenic HPV natural history and persistence as a risk factor for HPV-related OPC. This proposal capitalizes on a funded (CPRIT: RP2000025) OPC screening trial (1500 men; TRINITY Study: NCT 02897427) and would extend this work outside of a clinical trial design to explore both novel assays and self-collection and include women and those with limited health care access. Objective: To evaluate test characteristics, feasibility, and acceptance of non-invasive self-collected samples for HPV-related cancer screening and monitoring. Hypothesis: Novel self-sampling approaches / assays are feasible with equivalent performance to clinic-based / blood sampling and will be acceptable to both patients and the general population. To accomplish these objectives, the following specific aims are proposed: Aim 1: OPC Patient Cohort: To establish test characteristics of novel ctmHPVDNA and HPV16 E Ab assays using self-collected oral rinse, unstimulated saliva, and urine samples compared to tumor HPV status and clinic-based / blood samples. Aim 2: General Population Cohort: To document the feasibility of remote self-sampling (oral rinse, saliva, and urine) for novel ctmHPVDNA and HPV16 E Ab assays, as well as presence of oral oncogenic HPV. Design: A prospective cohort study of 100 patients with OPC (Aim 1), and 1,100 individuals aged 45-69 years from the general population (Aim 2). Presence of ctmHPVDNA will be determined using the NavDx assay (Naveris, Waltham, MA). HPV16 E Ab testing will be performed using a RAPID ELISA (ASU). Oral oncogenic HPV testing of oral rinse samples will be completed using Roche Cobas system with type-specific analysis using the SPF10-PCR-DEIA-LiPA25 assay. For Aim 1, test characteristics of the biomarker assays will be calculated based on the reference standard, OPC tumor HPV status. The new tests will also be compared to the non- reference standard (blood). For Aim 2, descriptive statistics will document successful completion rates of self- sampling and subsequent assay testing, and clinical findings described for the biomarker positive. Prevalence and 18-month persistence of oral oncogenic HPV will also be documented for the general population cohort.