[1294] Comparing Biomarkers for Tissue Detection of HPV-Associated Oropharyngeal Cancer

Patrizia Morbini, Barbara Dal Bello, Paola Alberizzi. Pavia University, Pavia, Italy; IRCCS Policlinico S. Matteo, Pavia, Italy

Background: Human papillomavirus (HPV)16 infection-associated oropharingeal squamous cell carcinomas (OPSCC) have relevant prognostic and therapeutic implications. Several algorythms have been proposed for their identification, however only recently has the virus transcriptional activity been recognized as the marker of virus-induced oncogenesis and the gold standard for test validation. In situ hybridization (ISH) for detection of genotype-specific mRNA of HPV E6/7 genes allows to assess on routine bioptic samples HPV oncogene transcription, avoiding the need of fresh tissue. This study was aimed at comparing the diagnostic accuracy of different current tests against HPV E6/7 mRNA ISH.
Design: 21 consecutive paraffin-embedded OPSCC were tested with ISH for HPV16 E6/7 mRNA and high risk (HR) HPV DNA, p16 immunostain, HPV DNA amplification with SPF10 primers and viral genotyping, and HPV16 E6 gene amplification. Test sensitivity and specificity were assessed with mRNA ISH as the gold standard.
Results: mRNA ISH identified viral transcripts in 8 of 21 cases, all positive by p16 stain, DNA ISH, HPV DNA and E6 gene amplification. All tests but DNA ISH were positive in some mRNA-negative cases.

The table summarizes test and statistic analysis results.

Table 1
TestN. positive (%)N. negative (%)Sensitivity95% CISpecificity95% CI
HPV16 mRNA ISH8 (38)13 (62)    
p1612 (57)9 (43)10063.1-10069.2338.6-90.9
SPF10 HPV DNA20 (95.2)1 (4.8)10063.1-1007.690.2-36.0
SPF10 HPV 1610 (47.6)11 (52.4)62.5024.5-91.561.5431.6-86.1
HPV16 E6 DNA amplification15 (71,4)6 (28.6)10063.1-10046.1519.2-74.9
HR HPV DNA ISH8 (38)13 (62)10063.1-10010075.3-100



Conclusions: Our results further validate the current diagnostic algorithm for HPV-associated OPSCC identification, which includes p16 stain and DNA ISH in p16-positive cases. The 100% correspondence of mRNA and DNA ISH results allows to reserve cumbersome mRNA ISH for research rather than diagnostic goals. The low specificity of PCR-based assays confirms the observation that HPV DNA amplification does not discriminate passenger (transcriptionally inactive) from oncogenic, transcriptionally active HPV infections. Moreover, integrated HPV16 can be missed when using primers amplifying the L1 region, which is lost upon viral integration.
Category: Head & Neck

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 201, Wednesday Morning

 

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