The Registry Study of Genetic Alterations of Oropharyngeal Cancer in Taiwan

Inclusion Criteria: 1. Ages 20 and above 2. Pathological reported as squamous cell carcinoma of head and neck 3. Available p16 immunohistochemical staining status (restricted to the OPSCC subgroup) 4. Participants have both archival tumor tissues from the primary head and neck SCC and from the first recurrent tumor (for the recurrence subgroup) 5. Recurrence status is defined as the reappearance of the disease occurring more than 6 months following curative surgery and/or chemoradiotherapy in the recurrence subgroup 6. Willingness to provide archival or newly obtained tumor tissues for current study proposal 7. Life expectancy more than 3 months 8. Patients fully understand the protocol with the willingness to have regular follow-up Exclusion criteria 1. Inability to cooperate by providing a complete medical history 2. No available tumor tissues for genetic testing 3. Undesirable compliance 4. Having a known additional malignancy that is progressing or has required active treatment within the past 3 years. Participants with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or carcinoma in situ (e.g., cervical carcinoma in situ) that have undergone potentially curative therapy are not excluded