Ren J, et al. - Researchers determined the prevalence of human papillomavirus (HPV) in squamous cell carcinoma of unknown primary in the head and neck (SCCUPHN) as well as assessed survival rates of patients with SCCUPHN by HPV status, by analyzing data from relevant observational studies and clinical trials identified from MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, EMBASE, Cochrane library and Web of Science. The pooled HPV prevalence of SCCUPHN was 49% in 17 SCCUPHN studies with 1,149 subjects and in 17 institution-matched oropharyngeal squamous cell carcinoma (OPSCC) studies involving 6,522 subjects, this estimate was only 10% lower compared to OPSCC prevalence in the underlying population. Overall, SCCUPHN patients vs OPSCC had lower HPV prevalence. Being HPV-positive was related to a survival benefit, which was similar in SCCUPHN as in OPSCCs, independent of continent.