Defining the minimum requirements for assigning a diagnosis of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (SCC) is increasingly important for the head-and-neck oncology community, according to a new study in the Journal of Clinical Pathology (February 23, 2011).
"While there are calls to undertake HPV testing for oropharyngeal SCCs within the diagnostic setting and for clinical trials, there are currently no internationally accepted standards," wrote researchers from King's College London Dental Institute.
They tested 142 tonsil SCCs using p16 immunohistochemistry (IHC), high-risk HPV DNA in situ hybridization (ISH), and HPV DNA polymerase chain reaction (PCR; GP5+/6+ primers).
They found high levels of agreement between pathologists for p16 IHC and HPV ISH scoring; however, around 10% of HPV ISH cases showed some interobserver discrepancy that was resolved by slide review. The combination of p16 IHC and HPV ISH classified 53% of the samples as HPV-positive, whereas the combination of p16 IHC and HPV PCR classified 61% of the samples as HPV-positive.
By employing a three-tiered, staged algorithm (p16 IHC/HPV ISH/HPV PCR), the authors said they were able to classify 98% of the cases as either HPV-positive (p16 IHC+/HPV DNA+; 62%) or HPV-negative (p16 IHC-/HPV DNA-; 35%).
The current study suggests that using a combination of p16 IHC/HPV ISH/HPV PCR, in a three-tiered, staged algorithm, in conjunction with consensus reporting of HPV ISH, leads to less equivocal molecular classification, the researchers concluded.
