Probes for HPV

Abstract

Background

Human papillomavirus (HPV)-driven oropharyngeal squamous cell carcinoma (OPSCC) represents a distinct tumour entity in comparison to HPV-negative OPSCC. The clinical, radiological, morphological features and distribution of HPV E6/E7 mRNA were investigated in resected specimens of OPSCC.

Methods

We retrieved formalin-fixed, paraffin-embedded whole section slides from 24 p16/HPV-DNA positive and 18 p16/HPV-DNA negative primary tumours and 16 corresponding metastases in patients with early-stage OPSCC who underwent planned curative or diagnostic primary transoral robotic surgery. A detailed clinicoradiological and histopathological investigation of the tumours was performed along with detection of HPV E6/E7 mRNA by in situ hybridisation.

Results

HPV-driven OPSCC was characterised by non-keratinising morphology and was dominated by a cohesive invasion pattern at the leading edge of the tumour. Dysplastic zones of the squamous epithelium were strictly located in the tonsillar crypts in contrast to HPV-negative OPSCC which predominantly arised from the dysplastic surface epithelium. Thirteen HPV-driven OPSCC invaded through the tonsillar lymphoid compartment and into soft tissue, causing a stromal desmoplastic reaction. HPV mRNA was consistently but inhomogenously expressed in the entire tumour area and in the dysplastic squamous epithelium. There was no HPV expression in the adjacent normal epithelium and in the non-neoplastic tissues.

Conclusions

This study enhances the current understanding of HPV-driven OPSCC. Only tumours that invade through the lymphoid compartment induce a stromal desmoplastic reaction. A consistent but inhomogenous expression of E6 and E7 mRNA was found in tumour and dysplastic areas, emphasizing that the E6/E7 oncogenes are the driving factors in HPV-driven OPSCC.

High-risk human papillomavirus (HPV)-related oropharyngeal squamous cell carcinomas have a more favorable prognosis than HPV-negative ones. p16 immunohistochemistry has been recommended as a prognostic test in clinical practice. Several p16 antibodies are available, and their performance has not been directly compared. We evaluated three commercially available p16 antibody clones (E6H4, JC8 and G175-405) utilizing 199 cases of oropharyngeal squamous cell carcinoma from a tissue microarray, read by three pathologists with three different cutoffs for positivity: any staining, >50% and >75%. Positive predictive values for high-risk HPV status by RNA in situ hybridization for the E6H4, JC8 and G175-405 clones were 98%, 100% and 99% at the 75% cutoff, but negative predictive values were much more variable at 86%, 69% and 56%, respectively. These improved using the 50% cutoff, becoming similar for all three antibodies. Intensity varied substantially, with 85% of E6H4, 72% of JC8 and 67% of G175-405 showing strong (3+) intensity. With Kaplan-Meier survival plots at the 75% cutoff, the E6H4 clone showed the largest differential in disease specific and overall survival between p16-positive and -negative results. Decreasing the cutoff to 50% increased correlation with HPV in situ hybridization and improved the survival differential for the JC8 and G175-405 clones without worsening of performance for the E6H4 clone. Interobserver agreement was also assessed by kappa scores and was highest for the E6H4 clone. Overall, these study results show modest but important performance differences between the three different p16 antibody clones, suggesting that the E6H4 clone performs best because of strongest staining intensity, greatest differential in outcomes between positive and negative results, lowest interobserver variability, and lowest background, nonspecific staining. The results also suggest that a 75% cutoff is very functional but that, in this patient population with high HPV incidence, 50% and any staining cutoffs may be more effective, particularly for the non-E6H4 clones.

Abstract

OBJECTIVES/HYPOTHESIS:

Human papillomavirus (HPV)-positive and HPV-negative oropharyngeal squamous cell carcinoma (OPSCC) are distinct disease entities. Prognostic factors specific to each entity have not been adequately explored. Goals for this study were: 1) to determine whether HPV-positive and HPV-negative OPSCCs have distinct prognostic factors, and 2) to explore the prognostic significance of sex and race in OPSCC after HPV stratification STUDY DESIGN: Retrospective case series.

METHODS:

A retrospective review of 239 incident OPSCC patients from 1995 to 2012, treated at Johns Hopkins and University of California-San Francisco was conducted. Women and nonwhite races were oversampled. All analyses were stratified by tumor HPV in situ hybridization status. The effects of sex and race on survival were considered in Kaplan-Meier and unadjusted and adjusted Cox regression models.

RESULTS:

One hundred thirty-four (56.1%) OPSCC patients were HPV positive. On univariate analysis, women had better overall survival than men among HPV-positive (hazard ratio [HR]: 0.47, 95% confidence interval [CI]: 0.20-1.07; P = .06) but not HPV-negative (HR: 0.73, 95% CI: 0.43-1.24; P = .24) OPSCCs. On multivariate analysis, women with HPV-positive OPSCCs remained at lower risk of death (adjusted hazard ratio [aHR]: 0.34, 95% CI: 0.12-0.96; P = .04). Survival did not vary significantly by race among HPV-positive patients. Among HPV-negative patients, Hispanic patients had significantly better survival in unadjusted (HR: 0.27, 95% CI: 0.08-0.91; P = .04) but not adjusted (aHR: 0.93, 95% CI: 0.11-7.36; P = .94) analysis.

CONCLUSIONS:

Women with HPV-positive OPSCC may have improved overall survival compared to men. Sex does not play a prognostic role in HPV-negative OPSCC. There are no differences in prognosis by race among HPV-positive or HPV-negative patients.

Abstract

BACKGROUND:

Human papillomavirus (HPV)-related squamous cell carcinoma (SqCC) of the oropharynx is an epidemiologically and clinically distinct form of SqCC that is associated with an improved prognosis. However, HPV-related small cell carcinoma of the oropharynx is a rare and newly described variant that is associated with aggressive clinical behavior and poor outcomes. To date, fewer than 2 dozen reports of this entity exist in the literature, and there is no discussion of cytopathologic features. This article reports 6 cases and discusses the salient cytomorphologic findings, ancillary studies, and challenges when this entity is encountered.

METHODS:

Anatomic pathology archives were searched to identify patients with a diagnosis of HPV-related small cell carcinoma of the oropharynx. Medical records were reviewed to document the following: age, sex, smoking status, other relevant clinical history, primary location, treatment, and clinical outcome. Both p16 and high-risk HPV in situ hybridization (ISH) studies were positive in at least 1 specimen from each patient. The pathologic diagnoses, cytomorphologic characteristics, immunocytochemical stains, and HPV ISH studies were reviewed and recorded for all available cases.

RESULTS:

Six patients with 11 cytopathology specimens of HPV-related small cell carcinoma of the oropharynx were identified. The mean age was 61.3 years, and all patients died with widely metastatic disease (mean, 23 months; range, 12-48 months). Mixed small cell carcinoma and SqCC components were present in half of the cases.

CONCLUSIONS:

The identification of a small cell component can be reliably performed with cytology preparations and is crucial because this (and not the HPV status) determines the prognosis.