Table 1. Characteristics of studies.

Study	Methods	Key findings
Anantharaman et al. (2017)	Case-control study.	The proportion of OPSCC caused by HPV16 varies by geographic region with low proportions in Brazil, moderate proportions in Western Europe, and the majority in the U.S. being HPV16-positive.
Ang et al. (2010)	Retrospective study.	HPV status is a strong and independent prognostic factor for survival among patients with OPSCC.
Carpén et al. (2018)	Retrospective study.	OPSCC can be dichotomized in two distinct disease entities as defined by HPV status.
Chaturvedi et al. (2011)	Cross-sectional study.	Increases in the population-level incidence and survival of oropharyngeal cancers in the United States since 1984 are caused by HPV infection.
Chaturvedi et al. (2018)	Cross-sectional study.	HPV vaccination was associated with reduction in vaccine-type oral HPV prevalence among young US adults.
Chera et al. (2019)	Phase II Trial.	Clinical outcomes with a de-intensified chemoradiotherapy regimen of 60 Gy intensity-modulated radiotherapy with concurrent low-dose cisplatin are favorable in patients with human papillomavirus–associated OPSCC.
de Ferreira et al. (2021)	Cross-sectional study.	Drinkers and current smokers were less likely to be p16+.
D’Souza et al. (2007)	Case-control study	Oral HPV infection is strongly associated with oropharyngeal cancer among subjects with or without the established risk factors of tobacco and alcohol use.
D’Souza et al. (2009)	Cross-sectional study.	Oral sex and open-mouthed kissing are associated with the development of oral HPV infection.
D’Souza et al. (2014)	Multicenter prospective study.	Oral HPV16 DNA is commonly detected among patients with HPV-OPC at diagnosis, but not among their partners.
Fakhry et al. (2008)	Prospective study.	HPV status is associated with therapeutic response and survival on OPSCC patients.
Gillison et al. (2008)	Case-control study.	HPV+ HNSCCs and HPV- head and neck cancer have different risk factor profiles.
Gillison et al. (2012)	Cross-sectional study.	Among men and women aged 14 to 69 years in the United States, the overall prevalence of oral HPV infection was 6.9%.
Kreimer et al. (2013)	Cohort study.	HPV16 E6 seropositivity was present more than 10 years before diagnosis of oropharyngeal cancers.
Lassen et al. (2009)	Cohort study.	Expression of p16 has a major impact on treatment response and survival in patients with head and neck cancer treated with conventional radiotherapy.
López et al. (2014)	Cohort study.	Seropositivity for HPV16 E6 antibodies was correlated with improved Head and neck cancer survival and oropharyngeal cancer.
Menezes et al. (2020)	Population-based study	Emerging risk for HPV-related OPSCC in young people, which supports prophylactic HPV vaccination in this group.
Näsman et al. (2009)	Retrospective study.	A increase in tonsillar cancer mainly due to HPV infection.
Petito et al. (2017)	Retrospective study.
Posner et al. (2011)		HPV+ OPSCC has a different biology compared with HPV-.
Raman et al. (2019)	Retrospective study.	The increased awareness and complexity of treatment decisions related to OPSCC may affect times to diagnosis and treatment initiation in patients with HPV-positive disease.