A comparison of clinically utilized human papillomavirus detection methods in head and neck cancer

Detection of human papillomavirus in head and neck cancer has therapeutic implications. In-situ hybridization and immuno-histochemistry for p16 are used by surgical pathologists. We compared the sensitivity and specificity of three popular commercial tests for human papillomavirus detection in head and neck squamous cell carcinomas to a “gold standard” human papillomavirus PCR assay. One hundred-and-ten prospectively collected, formalin fixed tumor specimens were compiled onto tissue microarrays and tested for human papillomavirus DNA by in-situ hybridization with two probe sets: a biotinylated probe for high-risk human papillomavirus types 16/18 (Dako, CA), and a probe cocktail for 16/18 plus 10 additional high-risk types (Ventana, AZ). P16(INK4) expression was also assessed using a Pharmingen immuno-histochemistry antibody (BD Biosciences, CA). Tissue microarrays were stained and scored at expert laboratories. Human papillomavirus DNA was detected by MY09/11-PCR using Gold AmpliTaq and dot-blot hybridization on matched fresh frozen specimens in a research laboratory. Human papillomavirus 16 E6 and E7-RNA expression was also measured using RT-PCR. Test performance was assessed by receiver operating characteristic analysis. High-risk human papillomavirus DNA types 16, 18 and 35 were detected by MY-PCR in 28% of tumors, with the majority (97%) testing positive for type 16. Compared to MY-PCR, the sensitivity and specificity for high-risk human papillomavirus DNA detection with Dako in-situ hybridization was 21% (95%CI:7–42) and 100% (95%CI:93–100), respectively. Corresponding test results by Ventana in-situ hybridization were 59% (95%CI:39–78) and 58% (95%CI:45–71), respectively. P16 immuno-histochemistry performed better overall than Dako (p=0.042) and Ventana (p=0.055), with a sensitivity of 52% (95%CI:32–71) and specificity of 93% (95%CI:84–98). Compared to a gold standard human papillomavirus PCR assays, HPV detection by in-situ hybridization was less accurate for head and neck squamous cell carcinoma on tissue microarrays than p16 immuno-histochemistry. Further testing is warranted before these assays should be recommended for clinical human papillomavirus detection.