TP53 mutations and CDKN2A mutations/deletions are highly recurrent molecular alterations in the malignant progression of sinonasal papillomas

Sinonasal Papillomas-An Up-To-Date Review for Practicing Pathologists

Sinonasal papillomas are a group of uncommon benign neoplasms that often represent a diagnostic challenge for surgical pathologists due to their diverse morphologic features. Our understanding of the molecular pathogenesis of these tumors has made significant advances recently that have reinforced the histology-based classification that was introduced over 50 years ago. As some subtypes have features that overlap with other sinonasal tumors, including specific carcinomas such as DEK::AFF2 nonkeratinizing squamous cell carcinoma, being aware of their key diagnostic findings is vital for appropriate classification.

Retinol-binding protein type 1 expression predicts poor prognosis in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent malignancy worldwide, with high incidence and poor survival rates. RBP1 is highly expressed in several kinds of cancer and plays a potential prognostic factor. However, the relationship between RBP1 and HNSCC were analyzed based on The Cancer Genome Atlas (TCGA) database.

MATERIALS AND METHODS

RBP1 expression and clinical information were obtained from the Cancer Genome Atlas (TCGA) database. Tumor tissue and adjacent normal tissue of 6 HNSCC patients were collected to analyze the RBP1 mRNA expression level by quantitative PCR. Cox regression analysis was used to evaluate the prognostic values of RBP1 and clinical data in HNSCC. A nomogram was also established to predict the impact of RBP1 on prognosis based on Cox multivariate results. The methylation level of RBP1 in HNSC and its prognosis were analyzed in UALACN and MethSurv. Finally, the potential biological functions of RBP1 were investigated using gene set enrichment analysis (GSEA) and single sample GSEA (ssGSEA).

RESULTS

The mRNA expression levels of RBP1 were highly expressed in HNSCC tissue. The Cox analyses demonstrate that highly-expressed RBP1 is an independent prognosis marker(P < 0.05). ROC curve analysis showed that performances of RBP1 (area under the ROC curve: 0.887, sensitivity: 84.1%, specificity: 79.9%). The methylation was increased in HNSCC patients compared with normal subjects(P < 0.05) and was associated with better prognosis at sites cg06208339, cg12298268, cg12497564, cg15288618, cg20532370, cg23448348. Additionally, RBP1 expression is mildly associated with immune cell infiltration and immunological checkpoints.

CONCLUSION

RBP1 is overexpressed and associated with poor patient prognosis in head and neck squamous cell carcinoma.

Assessment of TP53 and CDKN2A status as predictive markers of malignant transformation of sinonasal inverted papilloma

The mechanism and predictive biomarkers of sinonasal inverted papilloma (IP) transformation into squamous cell carcinoma (SCC) are still unclear. We investigated the genetic mutations involved and the predictive biomarkers. Fourteen patients with SCC arising from IP and six patients with IPs without malignant transformation (sIP) were included. DNA was extracted separately from areas of normal tissue, IP, dysplasia, and SCC. Whole exome sequencing and immunohistochemistry was performed. Major oncogenic mutations were observed in the progression from IP to SCC. The most frequently mutated genes were TP53 (39%) and CDKN2A (27%). Mutations in TP53 and/or CDKN2A were observed in three of six IPs with malignant transformation (cIP); none were observed in sIPs. Tumor mutational burden (TMB) increased from IP to SCC (0.64/Mb, 1.11/Mb, and 1.25 for IP, dysplasia, and SCC, respectively). TMB was higher in the cIPs than in the sIPs (0.64/Mb vs 0.3/Mb). Three cIPs showed a diffuse strong or null pattern in p53, and one showed a total loss of p16, a distinct pattern from sIPs. Our result suggests that TP53 and CDKN2A status can be predictive markers of malignant transformation of IP. Furthermore, immunohistochemistry of p53 and p16 expression can be surrogate markers for TP53 and CDKN2A status.

Sinonasal (Schneiderian) Tumors in the Temporal Bone: Case Series and Systematic Review

BACKGROUND

Neoplasms derived from the sinonasal epithelium are a rare finding in the temporal bone, and their origins are controversial.

PURPOSE

To review the characteristics of sinonasal epithelial (previously known as Schneiderian) tumors occurring in the temporal bone.

DATA SOURCE

This was a 2-center case series and systematic review of MEDLINE, EMBASE, and the Web of Science through May 2021.

STUDY SELECTION

Patients with clinicopathologic evidence of temporal bone involvement by neoplasms of sinonasal epithelial origin were selected, with or without a history of prior primary sinonasal epithelial tumors.

DATA ANALYSIS

Clinical, radiologic, and pathologic data were extracted.

DATA SYNTHESIS

The systematic review included 56 studies and our 8 unpublished cases, totaling 76 cases of papillomas or squamous cell carcinomas in the temporal bone. Of these, 51% occurred secondary to sinonasal tumors, and 49% occurred primarily. Secondary tumors were usually metachronous (77%), with a median delay of 1 year from sinonasal-to-temporal bone tumor diagnosis. Most cases were unilateral (90%); bilateral temporal bone involvement occurred only as secondary ("trilateral") tumors. Unilateral secondary tumors had ipsilateral (81%) or bilateral (19%) sinonasal counterparts. Secondary tumors were more likely to be malignant (OR, 6.7, P < .001).

LIMITATIONS

The review was based on case reports and small case series, which are subject to reporting bias.

CONCLUSIONS

The observed tumor patterns support the hypothesis that the Eustachian tube facilitates the spread of sinonasal epithelium-derived neoplasms from the sinonasal cavity to the temporal bone. Transtubal spread of sinonasal epithelium-derived neoplasms should be considered among the rare causes of middle ear 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.

Evaluation of high-risk human papillomavirus in sinonasal papillomas and squamous cell carcinomas

The sinonasal tract is considered a second hotspot for human papillomavirus (HPV)-related tumors in the head and neck, with HPV being identified in up to 62% of squamous cell carcinomas (SCCs) and 38% of papillomas. There is limited data from geographical regions with low prevalence of high-risk (HR)-HPV on the association of HR-HPV in sinonasal neoplasms and on utility of p16 as a surrogate marker. p16 immunohistochemistry, HR-HPV mRNA ISH and quantitative real-time PCR (qPCR) were performed on a retrospective cohort of sinonasal papillomas and SCCs. KRAS mutation analysis was done in oncocytic papillomas. p16 positivity was present in 22/142 cases (15.5%) including eight inverted papillomas, one oncocytic papilloma (OP), and 13 SCC. Among these, mRNA ISH showed HR-HPV in the OP and two SCC, while another SCC was found to harbour HPV18 by qPCR. Two HPV-associated SCCs had foci of OP. mRNA ISH was negative in all p16 negative cases. p16 immunohistochemistry showed 68% concordance with mRNA ISH, and had sensitivity and negative predictive value of 100%; specificity was 67%, and positive predictive value was 14.3%. Association with HR-HPV in sinonasal papillomas and SCC is rare, and may be seen in cases demonstrating oncocytic morphology. p16 immunohistochemistry has low specificity and positive predictive value in low-prevalence populations; thus, reflex direct HR-HPV testing should be performed in p16 immunopositive cases. This two-step approach is viable in resource-limited settings, as the proportion of p16 positive cases is small.

Adult granulosa cell tumor of the testis with malignant tendency: A case report with genetic analysis using high-throughput sequencing

BACKGROUND

The adult granulosa cell tumor of the testis is a rare sex-cord/stromal tumor, with a potentiality for late recurrence and metastasis. Because of its rarity, this tumor is poorly understood, particularly in terms of its molecular features. As a result, it is necessary to register each occurrence in order to study the evolution of this rare malignancy and develop therapeutic strategies.

METHODS

A 50-year-old man discovered a painless right testicular mass unexpectedly, and the mass steadily expanded for 2 months. Ultrasonography showed a 5.2 cm × 4.0 cm × 3.6 cm mass in the right testicle. A right radical orchiectomy was performed on September 7, 2016. The pathologic diagnosis was a testicular adult granulosa cell tumor. The post-computed tomography scans and bone scintigraphy ruled out distant metastases. A high-throughput sequencing of 520 cancer-related genes revealed FOXL2 C134W, CDKN2A E87Gfs*24, TP53 S183*, TERT c.-124C > T, and H3F3A K28R mutations in this case. Because the patient stated he would be unable to return to the hospital for a follow-up appointment on time, he elected to have 4 cycles of adjuvant chemotherapy BEP (bleomycin, etoposide, and cisplatin) after the right radical orchiectomy.

RESULTS

The patient has not had a clinical recurrence or metastasis in 6 years.

CONCLUSION

Surgery together with adjuvant chemotherapy may be useful treatment options for these individuals with malignant tendencies who are unable to visit the hospital for a follow-up appointment on time. Adult testicular granulosa cell tumors have a relatively complex genetic profile; their etiology is linked to a number of common driver genes, including TERT, CDKN2A, TP53, and H3F3A.

Low-grade papillary Schneiderian carcinoma with TP53 mutation: a case report and review of the literature

BACKGROUND

Low-grade papillary Schneiderian carcinoma (LGPSC) is a relatively new entity of the sinonasal tract and is characterized by a bland morphology simulating sinonasal papilloma, invasive growth pattern with pushing borders, and aggressive clinical behavior with multiple recurrences and metastatic potential. Recently, DEK::AFF2 fusions were identified in LGPSC. However, some LPGSCs lack DEK::AFF2 fusion, and the molecular features of these tumors have not been clarified.

CASE PRESENTATION

A 69-year-old man presented with a discharge of pus from his left cheek. Computed tomography revealed a mass involving the left maxillary sinus, ethmoid sinus, and nasal cavity with the destruction of the orbital wall. The biopsy specimens showed that the tumor had a predominantly exophytic, papillary growth and did not have an apparent stromal invasion. The tumor was composed of multilayered epithelium that showed bland morphology with a round to polygonal shape, abundant eosinophilic cytoplasm, and uniform nuclei. Dense neutrophilic infiltrates were focally present. Immunohistochemically, CK5/6 was strongly and diffusely positive, and p16 was negative. p63 was mainly positive in the basal layer, and EMA was predominantly expressed in the outermost cell layer. DNA-based targeted sequencing showed TP53 R175H mutation, whereas neither EGFR nor KRAS mutation was identified. Reverse transcription polymerase chain reaction and fluorescence in situ hybridization revealed no DEK::AFF2 fusion.

CONCLUSIONS

We describe the first case of TP53-mutant LGPSC and review the literature. LGPSC is a genetically heterogeneous entity, and the recognition of this rare entity and comprehensive assessment of clinicopathological and molecular findings are crucial for the correct pathological diagnosis and clinical management.

Sinonasal Cancer: Improving Classification, Stratification and Therapeutic Options

The nasal cavities and paranasal sinuses are the site of origin of a wide spectrum of histologically and clinically distinct disease entities [...].

Tumors of the Nose and Paranasal Sinuses: Promoting Factors and Molecular Mechanisms-A Systematic Review

Sinonasal neoplasms are uncommon diseases, characterized by heterogeneous biological behavior, which frequently results in challenges in differential diagnosis and treatment choice. The aim of this review was to examine the pathogenesis and molecular mechanisms underlying the regulation of tumor initiation and growth, in order to better define diagnostic and therapeutic strategies as well as the prognostic impact of these rare neoplasms. A systematic review according to Preferred Reporting Items for Systematic Review and Meta-Analysis criteria was conducted between September and November 2022. The authors considered the three main histological patterns of sinonasal tumors, namely Squamous Cell Carcinoma, Intestinal-Type Adenocarcinoma, and Olfactory Neuroblastoma. In total, 246 articles were eventually included in the analysis. The genetic and epigenetic changes underlying the oncogenic process were discussed, through a qualitative synthesis of the included studies. The identification of a comprehensive model of carcinogenesis for each sinonasal cancer subtype is needed, in order to pave the way toward tailored treatment approaches and improve survival for this rare and challenging group of cancers.

Seborrheic Keratosis With Malignant Transformation (Invasive or Noninvasive Squamous Cell Carcinoma Arising in Seborrheic Keratosis): A Clinicopathologic and Immunohistochemical Study of 11 Cases

ABSTRACT

Seborrheic keratosis is a common benign neoplasm composed of basaloid keratinocytes. However, little is known about the malignant transformation of the tumor. Eleven cases of seborrheic keratosis with malignant transformation were analyzed. The 11 patients included 5 male patients and 6 female patients with a median age of 75 years at diagnosis (68-90 years). The tumors arose at various sites from the scalp (n = 3) to the lower leg (n = 2). The median tumor size was 12 (10-32) and 40 (20-75) mm in 7 noninvasive and 4 invasive cases, respectively. One patient exhibited in-transit skin metastasis. Histopathology of the malignant components resembled porocarcinoma or inverted follicular keratosis. Bowenoid and pagetoid spreading was frequently observed. The malignant components expressed cytokeratin 5/6 (100%) and GATA3 (73%), but not cytokeratin 7 (0%), cytokeratin 19 (9%), BerEP4 (0%), c-kit (0%), and NUT (0%). No significant immunoreactivity of YAP1 was observed in any of the cases. Mutant-type immunostaining of p53 and PTEN was observed in 91% and 82% of the cases, respectively. An increase in p16 expression was seen in 6 (86%) of the 7 cases with noninvasive carcinoma, although a loss of p16 immunoexpression was seen in the invasive carcinoma component in 3 (75%) of the 4 cases. This study demonstrated that seborrheic keratosis can undergo malignant transformation, particularly in large-sized lesions in elderly patients. Malignant components mimic porocarcinoma or inverted follicular keratosis. Malignant transformation induced by TP53 and PTEN mutations and tumor invasion by CDKN2A inactivating mutations are suggested in this study.

Epstein-Barr virus-associated leiomyosarcoma of the larynx in an adult patient with human immunodeficiency virus infection: Case report and review of the literature

We investigated the clinical features, treatment, and prognosis of laryngeal leiomyosarcoma (LLMS) and Epstein-Barr virus-associated (EBV-associated) LMS. We report a case of EBV-associated LLMS in an adult patient with HIV infection. We also conducted a review of the English-language literature on LLMS and EBV-associated leiomyosarcoma. To the best of our knowledge, 62 cases of LLMS and EBV-associated leiomyosarcoma have been reported to date. Of patients with LLS, 18.9% had distant metastases and 17.0% had local recurrence. The overall 5-year survival rate was 64.0%. Distant metastases affected the survival of patients with LLMS (p = 0.04). EBV-positive patients had a low survival rate (p = 0.01). Among patients with EBV-associated LMS, 8.2% had distant metastases and recurrence and the overall 5-year survival rate was 50.0%. EBV-associated LLMS is rare. The EBV infection might be a poor prognostic factor of LLMS.

Molecular Basis and Rationale for the Use of Targeted Agents and Immunotherapy in Sinonasal Cancers

Despite the progress of surgery, radiotherapy, and neoadjuvant chemotherapy, the prognosis for advanced sinonasal cancers (SNCs) remains poor. In the era of precision medicine, more research has been conducted on the molecular pathways and recurrent mutations of SNCs, with the aim of understanding carcinogenesis, helping with diagnosis, identifying prognostic factors, and finding potentially targetable mutations. In the treatment of SNC, immunotherapy is rarely used, and no targeted therapies have been approved, partly because these tumors are usually excluded from major clinical trials. Data on the efficacy of targeted agents and immune checkpoint inhibitors are scarce. Despite those issues, a tumor-agnostic treatment approach based on targeted drugs against a detected genetic mutation is growing in several settings and cancer subtypes, and could also be proposed for SNCs. Our work aims to provide an overview of the main molecular pathways altered in the different epithelial subtypes of sinonasal and skull base tumors, focusing on the possible actionable mutations for which potential target therapies are already approved in other cancer types.

Loss of p16 expression is a risk factor for recurrence in sinonasal inverted papilloma

BACKGROUND

The purpose of this study was to evaluate p16, p53, EGFR, pEGFR protein expression and HPV infection as possible markers of tumor progression in a series of sinonasal inverted papilloma (SNIP) and sinonasal squamous cell carcinoma (SNSCC).

METHODS

A series of 49 SNIP, 11 SNSCC associated with SNIP (SNIP-SNSCC) and 52 SNSCC not associated with SNIP were analyzed for p16, p53, EGFR, and phosphorylated EGFR (pEGFR) expression by immunohistochemistry. Human papillomavirus (HPV) infection status was evaluated by DNA-PCR. Results were correlated to clinical and follow-up data.

RESULTS

Reduced or loss of p16 expression was observed in 18% SNIP, 64% SNIP-SNSCC and 87% of SNSCC. Reduced or loss p16 staining in SNIP correlated with shorter recurrent SNIP-free follow-up. In contrast, p16 expression was not predictive of recurrent SNSCC in cases with SNIP-SNSCC and SNSCC. P53, EGFR, and pEGFR expression did not differ between the tumor groups, nor were they related to recurrent SNIP-free follow-up or recurrent SNSCC. Oncogenic HPV types 16 and 18 were detected in 5% of SNIP and 18% of SNIP-SNSCC, but not in SNSCC. There was no correlation between HPV infection and &gt;70% p16 immunostaining.

CONCLUSIONS

HPV infection appears to play a minor role in SNIP and SNSCC and p16 immunostaining does not appear a valid surrogate marker for HPV. However, reduced or loss p16 expression may have prognostic value as a risk marker for recurrent SNIP.

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.

Increased Neutrophil Infiltration and Epithelial Cell Proliferation in Sinonasal Inverted Papilloma Compared to Contralateral Nasal Polyps

BACKGROUND

Sinonasal inverted papilloma (IP) is a rare and benign epithelial tumor in the sinonasal tract. Recent study suggested the potential role of chronic inflammation in the pathogenesis of IP. This study aims to compare the inflammatory pattern, the capacity of epithelial cell proliferation and EGFR mutation status of unilateral IP with contralateral polyp tissue.

METHODS

Sixteen patients with unilateral IP and contralateral nasal polyps (NP) were identified through a retrospective chart review. The neutrophil and eosinophil infiltration in IP and NP were assessed by immunostaining for neutrophil elastase and major basic protein (MBP). Immunohistochemistry was also used to assess the expression of FoxM1, Ki67 and cyclin D1 in IP tissue and contralateral NP. Sanger sequencing was used to evaluate the EGFR mutations.

RESULTS

The neutrophil count in IP was significantly higher than contralateral NP and 68.8% patients presented with neutrophilic inflammation, whereas only 37.5% contralateral NP tissue showed neutrophilic inflammation. The percentage of positive FoxM1-staining cells was significantly increased in IP, and positively correlated with the percentage of cells with positive staining for cyclin D1 and ki67 as well as neutrophil counts. EGFR exon 20 insertions were detected in 14 (87.5%) IP samples and no EGFR mutations were found in contralateral NP sample.

CONCLUSION

Our study demonstrated distinct inflammatory pattern between IP and contralateral NP and implied the oncogenic role of neutrophils in the pathogenesis of IP. EGFR mutations may be the early event to initiate IP development by enhancing epithelial cell proliferation.

Towards a Molecular Classification of Sinonasal Carcinomas: Clinical Implications and Opportunities

Simple Summary

In recent years, there have been several molecular and immunohistochemical additions to the pathologic diagnosis of sinonasal malignancies that could facilitate the identification of clinically relevant groups of sinonasal malignancies. Molecular profiling is progressively integrated in the histopathologic classification of sinonasal carcinomas, and it is likely to influence the management of these tumors in the near future. In this article we review the recent literature on molecular analysis and/or subtyping of sinonasal carcinomas and we discuss the possible clinical implications of a classification of sinonasal tumors based on their molecular features.

Abstract

Sinonasal carcinomas are a heterogeneous group of rare tumors, often with high-grade and/or undifferentiated morphology and aggressive clinical course. In recent years, with increasing molecular testing, unique sinonasal tumor subsets have been identified based on specific genetic alterations, including protein expression, chromosomal translocations, specific gene mutations, or infection by oncogenic viruses. These include, among others, the identification of a subset of sinonasal carcinomas associated with HPV infection, the identification of a subset of squamous cell carcinomas with EGFR alterations, and of rare variants with chromosomal translocations (DEK::AFF2, ETV6::NTRK and others). The group of sinonasal adenocarcinomas remains very heterogeneous at the molecular level, but some recurrent and potentially targetable genetic alterations have been identified. Finally, poorly differentiated and undifferentiated sinonasal carcinomas have undergone a significant refinement of their subtyping, with the identification of several new novel molecular subgroups, such as NUT carcinoma, IDH mutated sinonasal undifferentiated carcinoma and SWI/SNF deficient sinonasal malignancies. Thus, molecular profiling is progressively integrated in the histopathologic classification of sinonasal carcinomas, and it is likely to influence the management of these tumors in the near future. In this review, we summarize the recent developments in the molecular characterization of sinonasal carcinomas and we discuss how these findings are likely to contribute to the classification of this group of rare tumors, with a focus on the potential new opportunities for treatment.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Nasal Cavity, Paranasal Sinuses and Skull Base

The World Health Organization Classification of Head and Neck Tumours recently published the 5th edition. There are new entities, emerging entities, and significant updates to the taxonomy and characterization of tumor and tumor-like lesions, specifically in this article as it relates to nasal cavity, paranasal sinuses and skull base. Importantly, the number of diagnostic entries has been reduced by creating category-specific chapters for soft tissue, hematolymphoid, melanocytic, neuroectodermal, and metastatic tumors. Bone and salivary gland tumors are also not separately reported in the sinonasal tract, but included in the jaw and salivary gland sections, respectively. Repetition of characteristic entities in each anatomic site was also reduced, instead highlighting only the unique features in each anatomic site. Two new entities (SWI/SNF complex-deficient sinonasal carcinomas and HPV-related multiphenotypic sinonasal carcinoma) will be highlighted in this review, with a discussion of several emerging entities. There is a short description of updated information for all 24 diagnostic entities included in this edition to allow the reader a snapshot of current state of knowledge, but to encourage more investigation and further broaden understanding of these diverse and rare entities.

EGFR Exon 20 Insertion Mutations in Sinonasal Squamous Cell Carcinoma

Recurrent epidermal growth factor receptor (EGFR)-activating mutations have been identified in a rare form of head and neck cancer known as sinonasal squamous cell carcinoma (SNSCC), a malignant disease with a 5-year mortality rate of ~40%. Interestingly, the majority of EGFR mutations identified in patients with primary SNSCC are exon 20 insertions (Ex20ins), which is in contrast to non-small-cell lung cancer (NSCLC), where the EGFR exon 19 deletion and L858R mutations predominate. These studies demonstrate that EGFR Ex20ins mutations are not exclusive to lung cancer as previously believed, but are also involved in driving SNSCC pathogenesis. Here we review the landscape of EGFR mutations in SNSCC, with a particular focus on SNSCC associated with inverted sinonasal papilloma (ISP), a benign epithelial neoplasm. Taking lessons from NSCLC, we also discuss potential new treatment options for ISP-associated SNSCC harbouring EGFR Ex20ins in the context of targeted therapies, drug resistance and precision cancer medicine. Moving forward, further basic and translational work is needed to delineate the biology of EGFR Ex20ins in SNSCC in order to develop more effective treatments for patients with this rare disease.

Mismatch Repair Deficiency and Somatic Mutations in Human Sinonasal Tumors

Simple Summary

Sinonasal carcinomas are rare tumors with an overall poor prognosis. Due to limitations in local therapeutic approaches, systemic neo-adjuvant or adjuvant therapies are becoming increasingly important in order to improve patient outcome. This study aimed to examine potentially therapeutic targetable molecular alterations in different sinonasal tumors, including deficiency in mismatch repair proteins and microsatellite instability as well as driver mutations. According to our results, immunohistochemical (IHC) analysis of mismatch repair (MMR) proteins and sequencing-based panel analysis should be integrated into the diagnostics of clinically aggressive inverted sinonasal papilloma (ISP) and sinonasal squamous cell carcinoma (SNSCC) in order to enable the therapeutic possibility of a targeted therapy.

Abstract

Due to limitations in local therapy approaches for sinonasal tumors, improvement in systemic therapies plays a pivotal role for prolongation of the patient’s survival. The aim of this study was to examine potential biomarkers, including deficiency in mismatch repair proteins (dMMR)/microsatellite instability (MSI-H) in sinonasal cancers and their precancerous lesions. A comprehensive analysis of 10 sinonasal cancer cell lines by whole exome sequencing, screening 174 sinonasal tumors by immunohistochemistry (IHC) for mismatch repair deficiency and next generation sequencing (NGS) of 136 tumor samples revealed a dMMR/MSI-H sinonasal squamous cell carcinoma (SNSCC) cell line based on a somatic missense mutation in MLH1 and an overall frequency of dMMR/MSI-H SNSCC of 3.2% (4/125). Targetable EGFR mutations were found in 89.3% (25/28) of inverted sinonasal papilloma (ISP) and in 60% (6/10) of ISP-associated carcinomas. While PIK3CA and EGFR mutations were not mutually exclusive, KRAS mutated tumors were an EGFR-wildtype. The effect of potential driver mutations in FGFR2, FGFR3, BRAF, HRAS, MAP2K1, PTEN, NOTCH1 and CARD11 need further investigation. Our results suggest that biomarker testing, including MMR-IHC and NGS panel analysis, should be integrated into the diagnostics of clinically aggressive ISPs and SNSCC to assess prognosis and facilitate therapeutic decisions.

Aberrant Signaling Pathways in Sinonasal Intestinal-Type Adenocarcinoma

Sinonasal intestinal-type adenocarcinoma (ITAC) is strongly related to occupational exposure to wood and leather dust, however, little is known on the genetic alterations involved in tumor development and progression. The aim of this study was to identify tumorigenic signaling pathways affected by gene mutations and their relation to clinical features. We applied whole exome sequencing of 120 cancer-related genes in 50 ITACs and analyzed the signaling activity of four specific pathways frequently affected by mutations. Genes involved in DNA damage response showed somatic mutations in 30% of cases, including four tumors that also harbored germline mutations. Genes in Wnt, MAPK and PI3K pathways harbored mutations in 20%, 20% and 24% of cases, respectively. Mutations and copy number gains in receptor tyrosine kinases possibly affecting MAPK and PI3K pathways occurred in 44% of cases. Expression of key pathway proteins showed no correlation to mutations in these pathways, except for nuclear β-catenin and APC/CTNNB1 mutation. No specific gene mutation, mutated pathway, nor pathway activity level showed correlation to clinical data or survival. In addition, a similar mutational profile was observed among histological subtypes. The wide spectrum of gene mutations suggests that ITAC is a genetically heterogeneous without specific characterizing gene mutations.

HPV-Associated Benign Squamous Cell Papillomas in the Upper Aero-Digestive Tract and Their Malignant Potential

Squamous cell papilloma (SCP) in the upper aero-digestive tract is a rare disease entity with bimodal age presentation both at childhood and in adults. It originates from stratified squamous and/or respiratory epithelium. Traditionally, SCPs have been linked to chemical or mechanical irritation but, since the 1980s, they have also been associated with human papillomavirus (HPV) infection. Approximately 30% of the head and neck SCPs are associated with HPV infection, with this association being highest for laryngeal papillomas (76–94%), followed by oral (27–48%), sinonasal (25–40%), and oropharyngeal papillomas (6–7%). There is, however, a wide variation in HPV prevalence, the highest being in esophageal SCPs (11–57%). HPV6 and HPV11 are the two main HPV genotypes present, but these are also high-risk HPVs as they are infrequently detected. Some 20% of the oral and oropharyngeal papillomas also contain cutaneous HPV genotypes. Despite their benign morphology, some SCPs tend to recur and even undergo malignant transformation. The highest malignant potential is associated with sinonasal inverted papillomas (7–11%). This review discusses the evidence regarding HPV etiology of benign SCPs in the upper aero-digestive tract and their HPV-related malignant transformation. In addition, studies on HPV exposure at an early age are discussed, as are the animal models shedding light on HPV transmission, viral latency, and its reactivation.

Low Grade Papillary Sinonasal (Schneiderian) Carcinoma: A Series of Five Cases of a Unique Malignant Neoplasm with Comparison to Inverted Papilloma and Conventional Nonkeratinizing Squamous Cell Carcinoma

There have been a few case reports and one small series of low grade papillary sinonasal (Schneiderian) carcinomas (LGPSC) which mimic papillomas but have overtly invasive growth and which occasionally metastasize. We describe the morphologic, clinical, immunohistochemical, and molecular features of five patients with LGPSC compared with eight cases each of inverted papilloma (IP) and conventional nonkeratinizing squamous cell carcinoma (SCC) with papillary growth. All LGPSC were nested with predominantly pushing invasion, no stromal reaction, and frequent surface papillary growth. All consisted of one cell type only, with polygonal cells with round nuclei, no (or limited) cytologic atypia, low mitotic activity, and prominent neutrophilic infiltrate. One patient had slightly more infiltrative bone invasion, another lymphovascular, perineural, and skeletal muscle invasion, and a third nodal metastasis after 17 years. By comparison, IPs had bland cytology, neutrophilic microabscesses, mixed immature squamous, goblet cell, and respiratory epithelium, and extremely low mitotic activity. Nonkeratinizing SCCs had basaloid-appearing cells with nuclear pleomorphism, brisk mitotic activity, and apoptosis. All LGPSC were p63 positive. Mitotic activity and Ki67 indices were significantly higher for LGPSCs than IPs and significantly lower than NKSCCs, while p53 immunohistochemistry in LGPSC was identical to nonkeratinizing SCC and higher than for IP. Sequencing showed all five tumors to harbor a MUC6 mutation, one tumor to harbor CDKN2A and PIK3R1 mutations, and one tumor to harbor a NOTCH1 mutation. All LGPSC lacked EGFR and KRAS mutations and lacked copy number variations of any main cancer genes. At a median follow up of 12 months, two LGPSC recurred locally, and one patient died after massive local recurrences and nodal metastases. LGPSC is a distinct, de novo sinonasal carcinoma that can be differentiated from papillomas by morphology and selected immunohistochemistry.