Association of an intact E2 gene with higher HPV viral load, higher viral oncogene expression, and improved clinical outcome in HPV16 positive head and neck squamous cell carcinoma

• Published in: PloS one 2018-02, Vol.13 (2), p.e0191581-e0191581
• Main Authors: Anayannis, Nicole V, Schlecht, Nicolas F, Ben-Dayan, Miriam, Smith, Richard V, Belbin, Thomas J, Ow, Thomas J, Blakaj, Duk M, Burk, Robert D, Leonard, Sarah M, Woodman, Ciaran B, Parish, Joanna L, Prystowsky, Michael B
• Format: Article
• Language: English
• Subjects: Alphapapillomavirus - genetics; Alphapapillomavirus - isolation & purification; Biology and life sciences; Cancer; Carcinoma, Squamous Cell - therapy; Carcinoma, Squamous Cell - virology; Cell cycle; Cervical cancer; Clinical outcomes; Complications and side effects; Cyclin-dependent kinase inhibitors; Deoxyribonucleic acid; Disruption; DNA; DNA methylation; DNA-Binding Proteins - genetics; E2 gene; Epidemiology; Female; Gene disruption; Gene expression; Genes; Genetic aspects; Genomes; Head; Head & neck cancer; Head and neck cancer; Head and Neck Neoplasms - therapy; Head and Neck Neoplasms - virology; Human papillomavirus; Humans; Infections; INK4 protein; Male; Medical prognosis; Medicine; Medicine and Health Sciences; Middle Aged; Migraine; Neoplasm Recurrence, Local; Oncogene Proteins, Viral - genetics; Oncogenes; Oropharyngeal cancer; Oropharyngolaryngeal carcinoma; Otolaryngology; Papillomavirus infections; Pathology; Patient outcomes; Physicians; Physiological aspects; Polymerase Chain Reaction; Proteins; Regional analysis; Research and Analysis Methods; Risk factors; Squamous cell carcinoma; Squamous Cell Carcinoma of Head and Neck; Survival; Test procedures; Tumors; Viral Load
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0191581

To assess the relationship of E2 gene disruption with viral gene expression and clinical outcome in human papillomavirus (HPV) positive head and neck squamous cell carcinoma, we evaluated 31 oropharyngeal and 17 non-oropharyngeal HPV16 positive carcinomas using two PCR-based methods to test for disruption of E2, followed by Sanger sequencing. Expression of HPV16 E6, E7 and E2 transcripts, along with cellular ARF and INK4A, were also assessed by RT-qPCR. Associations between E2 disruption, E2/E6/E7 expression, and clinical outcome were evaluated by Kaplan-Meier analysis for loco-regional recurrence and disease-specific survival. The majority (n = 21, 68%) of HPV16 positive oropharyngeal carcinomas had an intact E2 gene, whereas the majority of HPV16 positive non-oropharyngeal carcinomas (n = 10, 59%) had a disrupted E2 gene. Three of the oropharyngeal tumors and two of the non-oropharyngeal tumors had deletions within E2. Detection of an intact E2 gene was associated with a higher DNA viral load and increased E2/E6/E7, ARF and INK4A expression in oropharyngeal tumors. Oropharyngeal carcinomas with an intact E2 had a lower risk of loco-regional recurrence (log-rank p = 0.04) and improved disease-specific survival (p = 0.03) compared to tumors with disrupted E2. In addition, high E7 expression was associated with lower risk of loco-regional recurrence (p = 0.004) as was high E6 expression (p = 0.006). In summary, an intact E2 gene is more common in HPV16 positive oropharyngeal than non-oropharyngeal carcinomas; the presence of an intact E2 gene is associated with higher HPV viral load, higher viral oncogene expression, and improved clinical outcome compared to patients with a disrupted E2 gene in oropharyngeal cancer.