TLR5 and TLR7 are differentially expressed in human papillomavirus-positive and negative base of tongue squamous cell carcinoma, and TLR7 may have an independent prognostic influence

Background: Human papillomavirus-positive (HPV+) base of tongue squamous cell carcinoma (BOTSCC) has a better outcome than corresponding HPV- cancer. TLR5 and TLR7 expression was previously shown to differ depending on HPV - status and correlate with outcome in oropharyngeal squamous cell carcinoma. Aims/objectives: For validation, TLR5 and TLR7 were analyzed in a BOTSCC-cohort for correlation with HPV, survival, CD4(+) and CD8(+) tumor-infiltrating lymphocyte (TIL) counts, the latter being a well-documented prognostic marker. Materials and methods: BOTSCC biopsies, (49HPV(+)/28HPV(-)) were analyzed by immunohistochemistry for TLR5 and TLR7, and correlated with the above parameters. Results: TLR5 expression was more frequently absent/weak than medium/strong in HPV+ compared to HPV- BOTSCC (p <.001). The opposite was observed for TLR7 (p <.007). TLR5 and TLR7 expression did not correlate to survival in either the HPV- or HPV+ cases, or to CD4(+) TILs. TLR5, (but not TLR7) expression was correlated to CD8(+) TIL counts (p = .023).Peer reviewe