EGFR mutations in sinonasal squamous tumors: oncogenic and therapeutic implications

International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors

BACKGROUND

Sinonasal neoplasms, whether benign and malignant, pose a significant challenge to clinicians and represent a model area for multidisciplinary collaboration in order to optimize patient care. The International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors (ICSNT) aims to summarize the best available evidence and presents 48 thematic and histopathology-based topics spanning the field.

METHODS

In accordance with prior International Consensus Statement on Allergy and Rhinology documents, ICSNT assigned each topic as an Evidence-Based Review with Recommendations, Evidence-Based Review, and Literature Review based on the level of evidence. An international group of multidisciplinary author teams were assembled for the topic reviews using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format, and completed sections underwent a thorough and iterative consensus-building process. The final document underwent rigorous synthesis and review prior to publication.

RESULTS

The ICSNT document consists of four major sections: general principles, benign neoplasms and lesions, malignant neoplasms, and quality of life and surveillance. It covers 48 conceptual and/or histopathology-based topics relevant to sinonasal neoplasms and masses. Topics with a high level of evidence provided specific recommendations, while other areas summarized the current state of evidence. A final section highlights research opportunities and future directions, contributing to advancing knowledge and community intervention.

CONCLUSION

As an embodiment of the multidisciplinary and collaborative model of care in sinonasal neoplasms and masses, ICSNT was designed as a comprehensive, international, and multidisciplinary collaborative endeavor. Its primary objective is to summarize the existing evidence in the field of sinonasal neoplasms and masses.

An in vitro model and the underlying pathways of sinonasal inverted papilloma development

Recently, the specific association between Sinonasal inverted papilloma (SIP) and EGFR exon 20 mutations has been reported. To investigate the link between specific EGFR mutations and SIP development, we established organotypic raft culture system using nasal polyp-derived immortalized NP2 (iNP2) cells expressing EGFR exon 20 mutants or an exon 19 mutant, and SIP-derived iIP4 cells harboring P772_H773insPYNP mutation. In the raft culture, iIP4 cells showed the inverted growth pattern characteristic to SIP. Interestingly, iNP2 cells expressing EGFR exon 20 duplication mutants, S768_D770dup and N771_H773dup, but not of EGFR exon 19 mutant, E746_A750del, showed the inverted growth pattern. Enhanced activation of the PI3K/AKT signaling pathway was observed in iNP2_S768_D770dup and iIP4 cells, while increased MAPK signaling was found in iNP2_N771_H773dup. Increased cell migration and invasion were found in all cells carrying EGFR mutations when compared to iNP2 cells, and this effect was inhibited by either PI3K or MEK inhibitor. Notably, iNP2 cells expressing the N771_H773dup mutant showed the highest migration and invasion abilities. These results suggest that specific mutations in EGFR exon 20 play a crucial role in SIP development, partially though hyper-activation of the PI3K/AKT and MAPK signaling pathways. This study presents the first in vitro model for SIP development, which could facilitate further investigations into SIP pathogenesis and preclinical studies for new therapeutic agents.

Human Papillomavirus-Related Carcinomas of the Sinonasal Tract

Purpose of review

The sinonasal tract is home to a uniquely heterogenous collection of malignant tumors. Human papillomavirus (HPV) has been detected in a number of these, but the virus' role as an oncogenic driver or coincidental finding remains unclear. We aim to highlight five sinonasal tumor types and synthesize the prevalence, etiologic role, and known clinicopathologic relevance of HPV in each.

Recent findings

The last decade has seen an expansion of investigation into HPV's oncogenic and prognostic significance within sinonasal malignancies. The sinonasal tract poses challenges to HPV detection where p16 lacks value as an accurate surrogate. A growing body of data supports a potentially favorable clinical profile for certain sinonasal HPV-positive lesions.

Summary

HPV represents a potential biologically and clinically relevant factor for some sinonasal malignancies. Definitive conclusions regarding HPV's role as a potential oncogenic agent require routine testing using validated methodologies, genomic interrogation, and large-scale prospective studies.

EGFR and BRAF mutations in inverted sinonasal papilloma - a more complex landscape?

Inverted (Schneiderian) sinonasal papilloma (ISP) is a neoplasm derived from mucosa of the sinonasal tract characterized by local aggressive growth, a tendency to recur and an association with sinonasal carcinoma. The etiology of ISP remains unclear. Recently, identical mutations in exons 19 and 20 of the oncogene EGFR were reported in ISP and ISP-associated sinonasal carcinoma. Nevertheless, it remains unclear whether recurring ISPs show identical EGFR mutations at different time points or whether these mutations are identical throughout the respective ISP sample. We used Sanger sequencing to test 60 formalin-fixed paraffin embedded ISP samples from 40 patients regarding mutations in exons 19 and 20 of EGFR—together with exon 15 of BRAF. Overall, 32 samples of 22 patients showed a mutation in EGFR exon 20, whereas 28 samples of 18 patients showed none. No mutation in EGFR exon 19 was found in any sample. Four samples of four patients showed a BRAF exon 15 mutation. Interestingly, samples of four patients exhibited genetic heterogeneity, enabling us to report this in ISP for the first time.

Frequent KRAS and HRAS mutations in squamous cell papillomas of the head and neck

Squamous cell papilloma (SCP) is a benign neoplasm of the head and neck. Human papillomavirus (HPV) has been reported to be a tumourigenic factor for SCP. However, not all SCPs are positive for HPV, suggesting that other possible mechanisms are involved in their development. In this study, we examined the mutational status of 51 SCPs using targeted panel sequencing in addition to HPV status using GP5+/GP6+ PCR. HPV DNA was detected in 6 (12%) SCPs, while KRAS and HRAS mutations were detected in 18 (35%) and 17 (33%) SCPs, respectively. Notably, KRAS mutations, HRAS mutations and HPV infection were mutually exclusive. The larynx and trachea (4/7, 57%) were more preferentially infected by HPV than the other sites (2/44, 5%, p = 0.0019) and HPV was associated with multifocal development (4/5, 80%). In contrast, KRAS and HRAS mutations in SCPs were evenly distributed across the anatomical sites and found only in single SCPs. In conclusion, this study demonstrated that HPV was not frequently involved in SCPs and that RAS mutations were more common alterations. In contrast to inverted sinonasal papillomas and oncocytic sinonasal papillomas, SCP may not be a precursor lesion of carcinoma, because these aetiological events in SCP are distinct from squamous cell carcinoma in the same sites.

Comparative transcriptome analysis of sinonasal inverted papilloma and associated squamous cell carcinoma: Out-HOXing developmental genes

BACKGROUND

Sinonasal papilloma has a tendency toward local destruction, recurrence, and malignant transformation. This study aimed to unravel mechanisms in the malignant transformation of sinonasal papillomas using RNA-seq.

METHODS

The cohort consisted of 37 consecutive patients; tumor histology included a continuum spectrum (sinonasal papillomas/dysplastic/carcinomas-in-situ/invasive squamous cell carcinomas). These were microdissected and RNA was subjected to whole-transcriptome shotgun sequencing.

RESULTS

RNA-seq and pathway analysis showed that the highest expressed genes/potential drivers were development- and differentiation-related genes. The protein expression of six highly upregulated genes (HOXA9, EN1, DUX4, CA9, CD1a, and CK5/6) validated the RNA-seq results. HOXA9 and CA9 were found to be expressed in most of the carcinoma samples but were largely negative in papillomas; all of the CA9-negative carcinomas were recurrent.

CONCLUSIONS

We conclude that sinonasal carcinomas arising from papillomas are mainly defined by overexpressed developmental/homeobox genes, which provide the potential for transformation/plasticity, along with differentiation and proliferation behavior of neoplastic cells. Our results support HOXA9 and CA9 as biomarkers for carcinomas, with CA9 emerging as a predictive marker of recurrence.

Human papillomavirus (HPV) and somatic EGFR mutations are essential, mutually exclusive oncogenic mechanisms for inverted sinonasal papillomas and associated sinonasal squamous cell carcinomas

Background

Inverted sinonasal (Schneiderian) papilloma (ISP) is a locally aggressive neoplasm often associated with sinonasal squamous cell carcinoma (SNSCC). While the etiology of ISP is not well understood, human papillomavirus (HPV) has been detected in a subset of cases. Our group recently identified activating somatic EGFR mutations in the majority of ISP and ISP-associated SNSCC. However, the relationship between EGFR mutations and HPV infection has not been explored.

Patients and methods

We evaluated 58 ISP and 22 ISP-associated SNSCC (including 13 patients with matched ISP/SNSCC samples), as well as 14 SNSCC without clinical or pathologic evidence of an associated ISP. Formalin-fixed, paraffin-embedded samples were evaluated for EGFR mutations using Sanger sequencing and for HPV infection using GP5+/GP6+ PCR. HPV subtyping based on the L1 sequence was done for HPV positive cases including temporally distinct tumors for four patients. Clinicopathologic data including progression free survival was also analyzed.

Results

All ISP and ISP-associated SNSCC demonstrated either an EGFR mutation or HPV infection. HPV and EGFR mutation were mutually exclusive in all cases of ISP-associated SNSCC and all but one ISP; this case was only weakly HPV positive, and analysis of a prior temporally distinct ISP specimen from this patient failed to show HPV infection, suggesting transient infection/incidental colonization. HPV subtypes in ISP and ISP-associated SNSCC were predominantly low-risk, in contrast with SNSCC without ISP association, which showed frequent high-risk HPV. All paired ISP and associated SNSCC samples demonstrated concordant HPV status and EGFR genotypes. ISP progression to SNSCC was significantly associated with the presence of HPV infection and the absence of an EGFR mutation (log-rank = 9.620, P = 0.002).

Conclusions

Collectively our data show that EGFR mutations and HPV infection represent essential, alternative oncogenic mechanisms in ISP and ISP-associated SNSCC.

Human Papillomavirus-Associated Neoplasms of the Head and Neck

Human papillomavirus (HPV) is an essential causal factor in a subset of head and neck neoplasms, most notably oropharyngeal squamous cell carcinoma, for which HPV infection has important diagnostic, prognostic, and therapeutic implications. This article summarizes the current understanding of HPV-associated neoplasms of the head and neck, including the recently described carcinoma with adenoid cystic-like features. Salient clinical, gross, and microscopic features are discussed, and the utility of specific ancillary studies is highlighted.