Forrest plot with odds ratios (OR) of having HPV in tonsillar and base of tongue squamous cell carcinomas (TSCC and BOTSCC respectively) vs. “other” (i.e. walls of oropharynx, uvulae and soft palate) oropharyngeal squamous cell carcinoma (OPSCC) presented by molecular detection method. (A) OR (95% CI) of having HPV, defined by presence of HPV DNA by PCR, in TSCC/BOTSCC vs. “other” OPSCC. (B) OR (95% CI) of having HPV, defined by overexpression of p16 immunohistochemistry (IHC), in TSCC/BOTSCC vs. “other” OPSCC. (C) OR (95% CI) of having HPV, defined by an algorithm combining presence of HPV DNA and overexpression of p16 IHC, in TSCC/BOTSCC vs. “other” OPSCC.