Histological and genetic criteria define a clinically relevant subgroup of HPV-positive oropharyngeal carcinoma

Abstract

Introduction

Subgroups with a poorer prognosis exist among patients with human papillomavirus positive oropharyngeal squamous cell carcinoma (HPV-positive OPSCC). This study aims to identify histological and genetic differences within HPV-positive OPSCC and correlate these findings with patient outcomes.

Methods

The study included 102 OPSCC patients, all tested positive for high-risk HPV DNA and p16INK4a expression. Based on histomorphological classification (HPV Prediction Classification, HPV PC), all cases were categorized as either classic HPV-positive OPSCC (cHPV) or non-classic HPV-positive OPSCC (non-cHPV). Next-generation sequencing (NGS) of selected genes was performed on 55 tumor samples, correlating results with morphological status and survival.

Results

Of all cases, 49 % (n = 50/102) were categorized as non-cHPV, histomorphologically resembling HPV-negative OPSCC, and showed significantly poorer overall survival (p = 0.004) and five-year survival rate (5YS: 83.9 % vs. 58.4 %). Multivariate analyses identified HPV PC as an independent prognostic marker (p = 0.027). NGS revealed loss-of-Function (LOF) mutations in TP53 in three non-cHPV samples. Additionally, PIK3CA/PTEN mutations were found in 35.7 % (10/28) of non-cHPV cases. The cumulative burden of gene mutations was higher in the non-cHPV subgroup compared to the cHPV subgroup (n = 53, p = 0.1).

Conclusion

HPV PC distinguished two histomorphological subgroups within HPV-positive OPSCCs: cHPV with excellent prognosis and non-cHPV with poorer overall survival. Non-cHPV tumors also exhibited higher overall mutation rates, notably LOF-TP53 and PIK3CA/PTEN mutations. These morphological subtypes, along with their corresponding mutational profiles, warrant further investigation as potential biomarkers for de-escalation intervention trials.