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).

CONCLUSION AND SIGNIFICANCE

Absent/weak TLR5 and medium/strong TLR7 expression was validated as more frequent in HPV compared with HPV BOTSCC. A correlation between CD8 TIL counts, and TLR5 expression was disclosed, but not with TLR7. Therefore, it could be useful to investigate TLR7 further as a potential independent prognostic marker.