Human papillomavirus prevalence and cell cycle related protein expression in tonsillar squamous cell carcinomas of korean patients with clinicopathologic analysis

Assessment of the Mutation Profile of Tonsillar Squamous Cell Carcinomas Using Targeted Next-Generation Sequencing

Data regarding driver mutation profiles in tonsillar squamous cell carcinomas (TSCCs) remain scarce, limiting the understanding of its pathogenesis and unexpected behavior in the updated staging system. We investigated the incidence of clinically relevant mutations and their contribution in the prognosis of the condition, and their association with human papillomavirus (HPV) infection and adjuvant therapy. We subjected 43 surgically resected TSCC samples to targeted next-generation sequencing, determined their HPV status using polymerase chain reaction, and performed The Cancer Genomic Atlas and Gene Set Enrichment analyses. Thirty-five TSCC samples (81.4%) showed at least one oncogenic/likely oncogenic mutation among twenty-nine cancer-related genes. The top five mutated genes were TP53 (46.5%), PIK3CA (25.6%), PTEN (18.6%), EGFR (16.3%), and SMAD4 (14.0%). The EGFR pathway was the most frequently affected (51.2%), followed by the p53 (48.8%), PI3K (39.5%), and RTK (34.9%) pathways. The gene set enrichment analysis confirmed that the genes involved in signal transduction, such as growth factor receptors and second messengers, EGFR tyrosine kinase inhibitors, and PI3K signaling pathways, were mostly related with TSCCs. TP53 mutation was an independent prognostic factor predicting worse overall survival in the adjuvant therapy group. RTK mutations were related to survival in all patients and in the HPV-positive group, but multivariate analyses showed no significance. In conclusion, oncogenic/likely oncogenic mutations were relatively high in TSCCs, and TP53 and RTK mutations may be candidate predictors for poor prognosis in the adjuvant therapy and HPV-positive groups, respectively, under the updated staging system.

Negative Prognostic Implication of TERT Promoter Mutations in Human Papillomavirus-Negative Tonsillar Squamous Cell Carcinoma Under the New 8th AJCC Staging System

Telomerase reverse transcriptase gene promoter (TERTp) mutation is a potential candidate for pathogenesis and therapeutic target of tonsillar squamous cell carcinomas (TSCCs) in association with human papillomavirus (HPV). Their clinical relevance has not been validated under the new 8th American Joint Committee on Cancer (AJCC) staging system. We analyzed real-time peptide nucleic acid–mediated PCR and sequencing methods (TERTp mutation) and real-time PCR-based assay (HPV) in 80 surgically resected TSCCs. The 8th edition staging system improved the stratification of the early and advanced stages and between T or N categories for overall survival over the 7th edition. TERTp mutation was found in 7.5%, and HPV in 80.0% of the patients. The majority (83.3%) of TERTp mutation cases were HPV-positive TSCCs. Applying the 8th edition staging system, TERTp mutation was an independent factor of poor prognosis for disease-free survival (DFS) in TSCC patients, supporting the clinical significance of TERTp mutation in tonsil cancer. TERTp mutations were also negatively correlated with overall survival and DFS in HPV-negative TSCCs. Conclusively, TERTp mutation provides negative prognostic impact on survival of surgically managed tonsil cancers staged with the AJCC 8th edition.

Prevalence of high-risk human papillomavirus and its genotype distribution in head and neck squamous cell carcinomas

Background

High-risk (HR) human papillomavirus (HPV) is found in a subset of head and neck (HN) squamous cell carcinomas (SCCs). For oropharyngeal SCCs, HR HPV positivity is known to be associated with good prognosis, and a separate staging system for HPV-associated carcinomas using p16 immunohistochemistry (IHC) as a surrogate test has been adopted in the 8th American Joint Committee on Cancer staging system. We examined the HR HPV status and the genotype distribution in five HN subsites.

Methods

Formalin-fixed paraffin-embedded tissue sections were used for p16 IHC and DNA extraction. HPV DNA detection and genotyping were done employing either a DNA chip-based or real-time polymerase chain reaction–based method.

Results

During 2011–2019, a total of 466 SCCs were tested for HPV DNA with 34.1% positivity for HR HPV. Among HN subsites, the oropharynx showed the highest HR HPV prevalence (149/205, 75.1%), followed by the sinonasal tract (3/14, 21.4%), larynx (5/43, 11.6%), hypopharynx (1/38, 2.6%), and oral cavity (1/166, 0.6%). The most common HPV genotype was HPV16 (84.3%) followed by HPV35 (6.9%) and HPV33 (4.4%). Compared with HR HPV status, the sensitivity and specificity of p16 IHC were 98.6% and 94.3% for the oropharynx, and 99.2% and 93.8% for the tonsil, respectively.

Conclusions

Using a Korean dataset, we confirmed that HR HPV is most frequently detected in oropharyngeal SCCs. p16 positivity showed a good concordance with HR HPV DNA for oropharyngeal and especially tonsillar carcinomas. The use of p16 IHC may further be extended to predict HR HPV positivity in sinonasal tract SCCs.

Association Between Fibroblast Growth Factor Receptor 1 Gene Amplification and Human Papillomavirus Prevalence in Tonsillar Squamous Cell Carcinoma With Clinicopathologic Analysis

Amplification of fibroblast growth factor receptor 1 ( FGFR1) has been reported in many squamous cell carcinomas, and human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma has been characterized as a distinct subset with favorable prognosis. Here, we investigated the FGFR1 amplification and HPV status in tonsillar squamous cell carcinoma (TSCC) and analyzed the clinical characteristics. HPV in situ hybridization (HPV ISH) and FGFR1 fluorescence in situ hybridization (FISH) were performed using tissue microarray from 89 cases of TSCC. Fourteen of 89 (15.7%) TSCC cases had FGFR1 amplification, and HPV was detected in 59 of 89 (66.3%) cases. FGFR1 amplification status was not associated with HPV positivity ( p=0.765). Outcomes were not significantly different between FGFR1 amplified and non-amplified patients. Although FGFR1 amplified patients ( n=4) in the HPV ISH-negative group ( n=30) had a tendency for poorer overall survival, no statistical significance was identified ( p=0.150, log-rank). FGFR1 protein overexpression showed better disease-free survival ( p=0.031, log-rank) in HPV-negative TSCC. This study suggests FGFR1 amplification may be important in the pathogenesis of TSCC regardless of HPV status.