Source: ASCO.org

Background: Head and neck squamous cell carcinoma (HNSCC) constitutes approximately 3-5 percent of all cancers. Recent data suggest an increasing incidence rate among younger people who are often non-smokers and non-drinkers, which are believed to be caused by human papillomavirus (HPV) infection. HPV positive tumors are typically found in the oropharynx and have better response to treatment and better disease outcome despite more advanced nodal stages. Therefore, HPV-positive HNSCCs represent a unique clinical subgroup with a separate tumor entity. Methods: Patients treated for HNSCC from 2002 to 2006 at UNC hospitals and had banked tissue available were eligible for this study. Tissue microarrays (TMA) were generated in triplicate. Immunohistochemical (IHC) staining for p16 was performed and scored separately for nuclear staining and cytoplasmic staining. Human papilloma virus (HPV) staining was also carried out using monoclonal antibody E6H4. P16 expression, HPV status and other clinical features were correlated with progression-free (PFS) and overall survival (OS). Results: 135 patients had sufficient sample for this analysis. Median age of diagnosis was 57 years (range 20-82), with 68.9% males, 8.9% never smokers and 32.6 % never drinkers. 3 year OS rate and PFS rate was 63.0% and 54.1% respectively. Based on the p16 staining score, patients were divided into three groups: high nuclear any cytoplasmic staining group (HNAC), low nuclear low cytoplasmic staining group (LNLC) and low nuclear high cytoplasmic staining group (LNHC). HNAC and LNLC groups had significantly better overall survival than LNHC groups with hazard ratios of 0.01 and 0.37 respectively, after controlling for other factors, including HPV status. HNAC and LNLC groups also had better progression-free survival than LNHC group, although not significantly. A similar trend was observed in an independent patient population with comparable magnitude of effect. Conclusions: Different p16 protein localization suggested different survival outcomes: high nuclear p16 staining is an indication of better survival while high cytoplasmic p16 staining signals poor survival outcome; and this effect is beyond the effect of HPV infection.

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.