The primary goal of this study is to examine whether recurrence of HPV-associated OPSCC can be predicted by two factors: 1) mutations in genes called TRAF3 and CYLD, and 2) measurements of circulating HPV DNA in blood plasma. The study will also investigate whether HPV integration is associated with TRAF3 and CYLD mutations, and whether recurrence prediction improves when looking at HPV integration along with TRAF3 and CYLD mutations.

Inclusion Criteria:

• ≥ 18 years of age
• T0-T2 N2a-N3 M0 or T3-T4 N0-N3 M0 (AJCC 7th edition)
• Biopsy proven squamous cell carcinoma of the oropharynx or unknown primary
• No prior therapy
• No evidence of distant metastatic disease
• p16 positive = diffuse ≥ 70% tumor cell expression, with at least moderate (2/3+) staining intensity
• Planned for receipt of definitive cancer treatment
• ECOG Performance Status 0-1
• Patients must be deemed able to comply with the treatment plan and follow-up schedule.
• Patients must provide study specific informed consent prior to study entry

Exclusion Criteria: All subjects meeting any of the exclusion criteria at baseline will be excluded from study participation:

• Prior history of radiation therapy to the head and neck
• Prior history of head and neck cancer.
• Inadequate pre-treatment tissue sample for tumor genomic analyses

Patients with HPV+ oropharyngeal squamous cell carcinoma who will receive definitive cancer treatment.