Comprehensive Molecular Profiling of Olfactory Neuroblastoma Identifies Potentially Targetable FGFR3 Amplifications

Olfactory neuroblastoma mimics molecular heterogeneity and lineage trajectories of small-cell lung cancer

The olfactory epithelium undergoes neuronal regeneration from basal stem cells and is susceptible to olfactory neuroblastoma (ONB), a rare tumor of unclear origins. Employing alterations in Rb1/Trp53/Myc (RPM), we establish a genetically engineered mouse model of high-grade metastatic ONB exhibiting a NEUROD1+ immature neuronal phenotype. We demonstrate that globose basal cells (GBCs) are a permissive cell of origin for ONB and that ONBs exhibit cell fate heterogeneity that mimics normal GBC developmental trajectories. ASCL1 loss in RPM ONB leads to emergence of non-neuronal histopathologies, including a POU2F3+ microvillar-like state. Similar to small-cell lung cancer (SCLC), mouse and human ONBs exhibit mutually exclusive NEUROD1 and POU2F3-like states, an immune-cold tumor microenvironment, intratumoral cell fate heterogeneity comprising neuronal and non-neuronal lineages, and cell fate plasticity-evidenced by barcode-based lineage tracing and single-cell transcriptomics. Collectively, our findings highlight conserved similarities between ONB and neuroendocrine tumors with significant implications for ONB classification and treatment.

Recurrent Wnt Pathway and ARID1A Alterations in Sinonasal Olfactory Carcinoma

Sinonasal tumors with neuroepithelial differentiation, defined by neuroectodermal elements reminiscent of olfactory neuroblastoma (ONB) and epithelial features such as keratin expression or gland formation, are a diagnostically challenging group that has never been formally included in sinonasal tumor classifications. Recently, we documented that most of these neuroepithelial neoplasms have distinctive histologic and immunohistochemical findings and proposed the term "olfactory carcinoma" to describe these tumors. However, the molecular characteristics of olfactory carcinoma have not yet been evaluated. In this study, we performed targeted molecular profiling of 23 sinonasal olfactory carcinomas to further clarify their pathogenesis and classification. All tumors included in this study were composed of high-grade neuroectodermal cells that were positive for pankeratin and at least 1 specific neuroendocrine marker. A significant subset of cases also displayed rosettes and neurofibrillary matrix, intermixed glands with variable cilia, peripheral p63/p40 expression, and S100 protein-positive sustentacular cells. Recurrent oncogenic molecular alterations were identified in 20 tumors, including Wnt pathway alterations affecting CTNNB1 (n = 8) and PPP2R1A (n = 2), ARID1A inactivation (n = 5), RUNX1 mutations (n = 3), and IDH2 hotspot mutations (n = 2). Overall, these findings do demonstrate the presence of recurrent molecular alterations in olfactory carcinoma, although this group of tumors does not appear to be defined by any single mutation. Minimal overlap with alterations previously reported in ONB also adds to histologic and immunohistochemical separation between ONB and olfactory carcinoma. Conversely, these molecular findings enhance the overlap between olfactory carcinoma and sinonasal neuroendocrine carcinomas. A small subset of neuroepithelial tumors might better fit into the superseding molecular category of IDH2-mutant sinonasal carcinoma. At this point, sinonasal neuroendocrine and neuroepithelial tumors may best be regarded as a histologic and molecular spectrum that includes core groups of ONB, olfactory carcinoma, neuroendocrine carcinoma, and IDH2-mutant sinonasal carcinoma.

Update on olfactory neuroblastoma

Olfactory neuroblastomas are uncommon malignancies that arise from olfactory receptor cells located high in the nasal cavity. Accurate diagnosis plays a crucial role in determining clinical results and guiding treatment decisions. Diagnosis can be a major challenge for pathologists, especially when dealing with tumours with poor differentiation. The discovery of several molecular and immunohistochemical markers would help to overcome classification difficulties. Due to the paucity of large-scale studies, standardisation of diagnosis, treatment and prediction of outcome remains a challenge. Surgical resection by endoscopic techniques with the addition of postoperative irradiation is the treatment of choice. In addition, it is advisable to consider elective neck irradiation to minimise the risk of nodal recurrence. Molecular characterisation will help not only to make more accurate diagnoses but also to identify specific molecular targets that can be used to develop personalised treatment options tailored to each patient. The present review aims to summarise the current state of knowledge on histopathological diagnosis, the molecular biology and management of this disease.

Characterizing Immune Infiltration in Esthesioneuroblastoma Subtypes Through Gene Expression Deconvolution

BACKGROUND

Esthesioneuroblastoma (ENB) is a rare cancer deriving from the olfactory mucosa. Among the basal or neural genomic subtypes, the basal subtype is associated with poorer survival, poor differentiation, and higher levels of tumor-infiltrating immune cells (TIICs). The immune microenvironment of these ENB subtypes remains unclear. We used an established machine learning algorithm on ENB transcriptomic profiles.

METHODS

The authors characterized 22 immune cell populations using the CIBERSORTx deconvolutional machine learning pipeline on RNA sequencing data from 18 ENB cases. The characterization aimed to elucidate differences in relative proportions and populations of TIICs between basal and neural ENB.

RESULTS

No differences in age, Hyams, Dulguerov, IDH2 mutation, or PD-L1 expression were seen between basal and neural subtypes of ENB (P > 0.05). Also, no difference in median overall survival was appreciated (52.0 ± 13.1 months vs. 50.0 ± 43.2 months, P = 0.5). As a cohort, M2 macrophages were the most abundant subpopulation (14%) followed by naïve B cells (13%) and CD4 memory resting T cells (12%). No gross differences in CD20, CD4, or CD8 cells/mm2 were apparent on gross histology (P > 0.05). However, further analysis showed that activated CD4 memory T cells were significantly increased in the basal ENBs, whereas resting dendritic cells were increased in the neural ENB subtype. The TIIC profiles alone could not differentiate between basal and neural ENB, but did suggest immunoprofile differences.

CONCLUSIONS

Basal and neural subtypes display distinct TIIC involvement, which may impact their difference in outcome. These findings provide the framework for further investigation in novel immunomodulation strategies for ENB.

Olfactory neuroblastoma: diagnosis, management, and current treatment options

Olfactory neuroblastoma (ONB) is a rare neoplasm originating from the olfactory neuroepithelium representing 3-6% of tumors of the sinonasal tract. ONB require multi-disciplinary care. Historically, the gold standard surgical procedure for ONB has been open craniofacial resection. In the last years, endoscopic endonasal approaches have been largely introduced with lower complication rates, shorter hospital stay, and similar clinical outcome. Radiotherapy plays an important role in the management of ONB, however there are not generally accepted recommendations for its application. Although there is agreement that multimodal therapy is needed, the optimal use of chemotherapy is still unknown. The rarity of the disease, makes difficult to draw definitive conclusions about the role of systemic treatment in induction and concomitant setting.

Treatment outcomes and prognostic factors of esthesioneuroblastoma-a retrospective study from South India

Esthesioneuroblastoma (ENB) or olfactory neuroblastoma is a rare malignant neoplasm arising from the neural crest cells of the olfactory epithelium. The optimum treatment for this rare disease is still unclear. Most of the available literature on this rare head and neck tumour is limited to small retrospective series and single institutional reports. We conducted a retrospective study to investigate the clinical profile, treatment outcomes and prognostic factors of patients with ENB treated at a tertiary cancer centre in south India. Patients with a histopathological diagnosis of ENB treated from 2000 to 2019 were included. Patient demographics, tumour characteristics, stage, treatment details and outcome data were identified from medical records. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method and the log-rank test was used for comparison. The prognostic factors were identified using Cox regression analysis. Forty-two patients underwent treatment for ENB from 2000 to 2019. Twenty-six patients underwent surgery. Twelve patients received radical radiotherapy (RT) while 24 patients underwent adjuvant radiation. After a median follow-up of 71 months, the estimated OS and DFS at 4 years were 64.4% and 54%, respectively. The estimated 4-year OS for modified Kadish A, B, C and D stages was 75.0%, 90.9%, 56.4% and 0%, respectively. Modified Kadish stage, nodal involvement, orbital invasion, intracranial extension, surgery, RT treatment and use of chemotherapy were significant predictors of OS and DFS in univariate Cox regression analysis. Orbital invasion and RT treatment were significant predictors of DFS in the multivariate analysis as well. However, only RT treatment came out to be a significant predictor for OS in multivariate Cox regression analysis. Surgery is the mainstay of treatment. Adjuvant RT may improve local control and survival in advanced cases. Advanced modified Kadish stage, lymph node involvement and orbital invasion are associated with poor outcomes.

Proceedings of the 2023 North American Society of Head and Neck Pathology Companion Meeting, New Orleans, LA, March 12, 2023: Navigating New Developments in High Grade Sinonasal Neuroendocrine and Neuroectodermal Neoplasms

Although the definitions of sinonasal neuroendocrine and neuroectodermal neoplasms did not change substantially in the 5th edition WHO Classification of Head and Neck Tumours, the diagnosis of olfactory neuroblastoma (ONB), small cell neuroendocrine carcinoma, and large cell neuroendocrine carcinoma remains quite challenging in practice. Ambiguities surrounding the amount of keratin expression allowable in ONB and the amount of neuroendocrine differentiation seen in sinonasal undifferentiated carcinoma (SNUC) lead to significant diagnostic discrepancies at the high grade end of this tumor spectrum. Furthermore, a group of problematic neuroepithelial tumors that show overlapping features of ONB and neuroendocrine carcinoma have never been recognized in formal classification schemes. Since publication of the 5th edition WHO, two new tumor entities have been proposed that help resolve these problems. Olfactory carcinoma is defined by high grade keratin-positive neuroectodermal cells with frequent intermixed glands and shows recurrent Wnt pathway, ARID1A, and RUNX1 alterations. IDH2-mutant sinonasal carcinoma is a molecularly-defined category that encompasses tumors with undifferentiated (SNUC), large cell neuroendocrine, and neuroepithelial phenotypes. This review will provide a practical overview of these emerging entities and their application to diagnostic challenges in the post-WHO sinonasal neuroendocrine and neuroectodermal tumor classification.

Immunohistochemical Profiling and Staging in Esthesioneuroblastoma: A Single-Center Cohort Study and Systematic Review

OBJECTIVE

Esthesioneuroblastoma (ENB) is a rare sinonasal malignant neoplasm with 40% 5-year survival. Because of the rarity of the tumor, the optimal treatment and subsequent prediction of prognosis are unclear. We studied a modern series of patients with ENB to evaluate the association of immunohistochemical (IHC) markers and clinical stages/grades with outcomes.

METHODS

A single-center retrospective review of patients with ENB treated during a 25-year period was performed. A systematic literature review evaluating the prognostic benefits of current staging systems in evaluating survival outcomes in ENB was undertaken.

RESULTS

Among 29 included patients, 25 (85%) were treated surgically at our institution, with 76% of those endoscopically resected; 7 (24.1%) received chemotherapy, and 18 (62.1%) received radiation therapy. The 5-year overall survival (OS) was 91.3%, and 10-year OS was 78.3%. Progression-free survival at 5 and 10 years was 85.6% and 68.2%, respectively. A total of 36 distinct IHC markers were used to diagnose ENB but were inconsistent in predicting survival. A systematic literature review revealed predictive accuracy for OS using the Kadish, TNM, and Hyams staging/grading systems was 68%, 42%, and 50%, respectively.

CONCLUSIONS

This study reports the 5- and 10-year OS and progression-free survival in a modern series of patients with ENB. No traditional IHC marker consistently predicted outcome. Some novel reviewed markers show promise but have yet to enter clinical mainstream use. Our systematic review of accepted staging/grading systems also demonstrated a need for further investigation due to limited prognostic accuracy.

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.

Olfactory Neuroblastoma: Morphological Reappraisal and Molecular Insights with Quantum Leap in Clinical Perspectives

PURPOSE OF REVIEW

The purpose of review is to provide a comprehensive review of the literature focusing on the recent advances in the diagnosis, molecular underpinning, and targeted therapy of olfactory neuroblastoma (ONB).

RECENT FINDINGS

Studies focused on the molecular fingerprinting of ONB are critical to engage new promising treatment strategies. Molecular-based subtype classifications have been proposed (basal-like ONB and neural-like ONB) but are not widely used. The rationale for implementation of DNA methylation analysis and IDH2 sequencing in routine work-up for ONB is gaining recognition. Expression of somatostatin receptors (SSTR) in ONB open new avenues for both, diagnostic (especially metastatic disease) and new treatment protocols with somatostatin analogs. Olfactory carcinoma is proposed as a unifying diagnostic terminology pertinent to epithelial divergent differentiation in olfactory neuroblastoma. Molecular (genetic and epigenetic) efforts on olfactory neuroblastoma are promising; however further refinement is needed for employment of these biomarkers as clinical standard of care. Ongoing and future multi-institutional collaborative studies will contribute to further understanding of ONB biology and aid the development of targeted treatments for this disease.

A Review on Esthesioneuroblastoma

Background Esthesioneuroblastoma (ENB) is a rare, aggressive and malignant sinonasal tumour. This tumour makes for a very interesting study because ever since its mention in medical literature, although quite a lot of research has been put into it, a lot is yet to be known about it. Aim To summarize the available literature & document an article on the contemporary practises in the management of ENB. Methods A comprehensive literature review was done using Google Scholar and PubMed database with the key words: "esthesioneuroblastoma", "olfactory neuroblastoma", "Kadish" and "Hyams". Articles published in English were used. Articles published till April 2021 were reviewed. Conclusion ENB has a diverse histological appearance. This tumour has a bimodal age distribution without any gender predilection. Prompt identification and treatment is required for a favourable outcome and requires close collaboration of radiology, pathology, and rhinology. Staging, management and prognosis are determined by regional involvement in non-metastatic cases due to its proximity to neurological structures and locally destructive nature. Immunohistochemistry is a must for accurate diagnosis. Uni-modality of treatment has high chances of local recurrence. Multi-modality provides good results even in advanced stage. A combination of surgery and radiotherapy seems to be the optimum approach to treatment. The exact role of chemotherapy in treatment protocols is still unclear. Cervical lymph node metastases are commonly studied, however its management in patients who present without apparent nodal involvement is not yet clear. An extended follow-up period is recommended in all patients of ENB patients.

Molecular Biomarkers in Sinonasal Cancers: New Frontiers in Diagnosis and Treatment

Purpose of Review

Sinonasal tumors are rare and heterogeneous diseases which pose challenges in diagnosis and treatment. Despite significant progress made in surgical, oncological, and radiotherapy fields, their prognosis still remains poor. Therefore, alternative strategies should be studied in order to refine diagnosis and improve patient care.

Recent Findings

In recent years, in-depth molecular studies have identified new biological markers, such as genetic abnormalities and epigenetic variations, which have allowed to refine diagnosis and predict prognosis. As a consequence, new histological entities have been described and specific subgroup stratifications within the well-known histotypes have been made possible. These discoveries have expanded indications for immunotherapy and targeted therapies in order to reduce tumor spread, thus representing a valuable implementation of standard treatments.

Summary

Recent findings in molecular biology have paved the way for better understanding and managing such rare and aggressive tumors. Although further efforts need to be made in this direction, expectations are promising.

IDH2 R172 Mutations Across Poorly Differentiated Sinonasal Tract Malignancies: Forty Molecularly Homogenous and Histologically Variable Cases With Favorable Outcome

IDH2 R172 mutations occur in sinonasal undifferentiated carcinoma (SNUC), large-cell neuroendocrine carcinoma (LCNEC), sinonasal adenocarcinomas, and olfactory neuroblastoma (ONB). We performed a clinical, pathologic, and genetic/epigenetic analysis of a large IDH2-mutated sinonasal tumor cohort to explore their distinct features. A total 165 sinonasal/skull base tumors included 40 IDH2 mutants studied by light microscopy, immunohistochemistry, and genome-wide DNA methylation, and 125 IDH2 wild-type tumors used for comparison. Methylation profiles were analyzed by unsupervised hierarchical clustering, t-distributed stochastic neighbor embedding dimensionality reduction and assessed for copy number alterations (CNA). Thirty-nine histologically assessable cases included 25 (64.1%) SNUC, 8 (20.5%) LCNEC, 2 (5.1%) poorly differentiated adenocarcinomas, 1 (2.7%) ONB, and 3 (7.7%) IDH2-mutated tumors with ONB features. All cases were high-grade showing necrosis (82.4%), prominent nucleoli (88.9%), and median 21 mitoses/10 HPFs. AE1/AE3 and/or CAM 5.2 were positive in all and insulinoma-associated protein 1 (INSM1) in 80% cases. All IDH2 mutants formed one distinct group by t-distributed stochastic neighbor embedding dimensionality reduction separating from all IDH2 wild-type tumors. There was no correlation between methylation clusters and histopathologic diagnoses. Recurrent CNA included 1q gain (79.3%), 17p loss (75.9%), and 17q gain (58.6%). No CNA differences were observed between SNUC and LCNEC. IDH2 mutants showed better disease-specific survival than SMARCB1-deficient (P=0.027) and IDH2 wild-type carcinomas overall (P=0.042). IDH2-mutated sinonasal tumors are remarkably homogeneous at the molecular level and distinct from IDH2 wild-type sinonasal malignancies. Biology of IDH2-mutated sinonasal tumors might be primarily defined by their unique molecular fingerprint rather than by their respective histopathologic diagnoses.

The genomics and epigenetics of olfactory neuroblastoma: A systematic review

BACKGROUND

Olfactory neuroblastoma (ONB) or esthesioneuroblastoma (ENB) is a rare malignancy of the nasal cavity believed to arise from the olfactory epithelium. The goal of this study was to systematically review the genomics, epigenetics, and cytogenetics of ONB and to understand the potential clinical implications of these studies.

METHODS

A systematic literature review was performed for articles published before May 2020 using Cochrane, Embase, Pubmed, and Scopus databases. Inclusion criteria included genomics, cytogenetics, and epigenetics studies on ONB. Exclusion criteria included studies not in English or systematic reviews. Articles and abstracts were reviewed by two independent reviewers to reduce bias during article selection and synthesis of results. Of the 36 studies included in this review, 24 were research articles and 12 were abstracts.

RESULTS

Although recurrent mutations among ONB tumors are uncommon, alterations in TP53, DMD, PIK3CA, NF1, CDKN2A, CDKN2C, CTNNB1, EGFR, APC, cKIT, cMET, PDGFRA, CDH1, FH, SMAD4, FGFR3 and IDH2 genes have been reported in several recent studies. In addition, cytogenetic studies revealed that the landscape of chromosomal aberrations varies widely amongst ONB tumors.

CONCLUSIONS

The rare character of ONB has limited the sample size available for cytogenetic, genomic, and epigenetic studies and contributes to the limitations of this systematic review. Comprehensive genomic and epigenomic studies with larger cohorts are warranted to validate the initial reports summarized in this review and to identify potential therapeutic targets for ONB.

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

Sinonasal papillomas are benign epithelial tumors of the sinonasal tract that are associated with a synchronous or metachronous sinonasal carcinoma in a subset of cases. Our group recently identified mutually exclusive EGFR mutations and human papillomavirus (HPV) infection in inverted sinonasal papillomas and frequent KRAS mutations in oncocytic sinonasal papillomas. We also demonstrated concordant mutational and HPV infection status in sinonasal papilloma-associated sinonasal carcinomas, confirming a clonal relationship between these tumors. Despite our emerging understanding of the oncogenic mechanisms driving formation of sinonasal papillomas, little is currently known about the molecular mechanisms of malignant progression to sinonasal carcinoma. In the present study, we utilized targeted next-generation DNA sequencing to characterize the molecular landscape of a large cohort of sinonasal papilloma-associated sinonasal carcinomas. As expected, EGFR or KRAS mutations were present in the vast majority of tumors. In addition, highly recurrent TP53 mutations, CDKN2A mutations, and/or CDKN2A copy-number losses were detected; overall, nearly all tumors (n = 28/29; 96.6%) harbored at least one TP53 or CDKN2A alteration. TERT copy-number gains also occurred frequently (27.6%); however, no TERT promoter mutations were identified. Other recurrent molecular alterations included NFE2L2 and PIK3CA mutations and SOX2, CCND1, MYC, FGFR1, and EGFR copy-number gains. Importantly, TP53 mutations and CDKN2A alterations were not detected in matched sinonasal papillomas, suggesting that these molecular events are associated with malignant transformation. Compared to aerodigestive tract squamous cell carcinomas from The Cancer Genome Atlas (TCGA) project, sinonasal papilloma-associated sinonasal carcinomas have a distinct molecular phenotype, including more frequent EGFR, KRAS, and CDKN2A mutations, TERT copy-number gains, and low-risk human papillomavirus (HPV) infection. These findings shed light on the molecular mechanisms of malignant progression of sinonasal papillomas and may have important diagnostic and therapeutic implications for patients with advanced sinonasal cancer.

Gene Expression Profiling of Olfactory Neuroblastoma Helps Identify Prognostic Pathways and Define Potentially Therapeutic Targets

Simple Summary

The gene expression profile of ONB defines a group of patients with a dismal prognosis and identifies potentially targetable pathways. Better prognostic stratification may offer new tailored approaches for the treatment and follow-up of ONB. The integration of new therapeutic agents with standard surgical and RT strategies may improve the outcomes in cases with worse prognoses. Furthermore, the ontogenesis of ONB in basal and neural subtypes is mirrored by different transcriptional pathways, paving the way towards different therapeutic approaches.

Abstract

Olfactory neuroblastoma (ONB) is a rare sinonasal neoplasm with a peculiar behavior, for which limited prognostic factors are available. Herein, we investigate the transcriptional pathways altered in ONB and correlate them with pathological features and clinical outcomes. We analyze 32 ONB patients treated with curative intent at two independent institutions from 2001 to 2019 for whom there is available pathologic and clinical data. We perform gene expression profiling on primary ONB samples and carry out functional enrichment analysis to investigate the key pathways associated with disease-free survival (DFS). The median age is 53.5 years; all patients undergo surgery and a pure endoscopic approach is adopted in the majority of cases (81.2%). Most patients have advanced disease (stages III–IV, 81.2%) and 84.4% undergo adjuvant (chemo)radiotherapy. The median follow-up is 35 months; 11 (26.8%) patients relapse. Clinical characteristics (gender, stage and Hyams’ grade) are not associated with the outcomes. In contrast, TGF-beta binding, EMT, IFN-alpha response, angiogenesis, IL2-STAT5 and IL6-JAK-STAT3 signaling pathways are enriched in patients experiencing recurrence, and significantly associated with shorter DFS. Clustering of transcriptional profiles according to pathological features indicates two distinct molecular groups, defined by either cytokeratin-positive or -negative immunostaining. Definition of the characterizing ONB transcriptomic pathways may pave the way towards tailored treatment approaches.

Case report expanding the germline AXIN2- related phenotype to include olfactory neuroblastoma and gastric adenoma

BACKGROUND

Pathogenic AXIN2 variants cause absence of permanent teeth (hypodontia), sparse hair and eye brows (ectodermal dysplasia), and gastrointestinal polyps and cancer. Inheritance is autosomal dominant with variable penetrance. Only twenty- five patients have been reported from five families. A Mayo Clinic pilot program tested 3009 newly diagnosed cancer patients for pathogenic germline variants in 83 hereditary cancer genes, including AXIN2. We found only one patient with a pathogenic AXIN2 variant.

CASE PRESENTATION

The proband was a 49 year-old female who came to Otolaryngology clinic complaining of right-sided nasal obstruction. Biopsy of identified nasal polyp revealed olfactory neuroblastoma (esthesioneuroblastoma). Surgical resection with gross, total tumor resection was followed by radiation therapy. The patient enrolled in a clinical pilot of genetic testing and a pathogenic variant in AXIN2, c.1822del (p.Leu608Phefs*81) (NM_004655.3) was found. She was seen in Medical Genetics clinic and found to have a personal history of hypodontia. Her eyebrows, hair, and nails were all normal. She underwent upper endoscopy and colonoscopy. A four mm gastric adenoma was found and removed.

CONCLUSIONS

This is the first case reported on a patient with a pathogenic, germline AXIN2 variant and an olfactory neuroblastoma or a gastric adenoma. We propose that these could be features of the AXIN2 phenotype. The known association between gastric adenomas and familial adenomatous polyposis, the other Wnt/beta-catenin disorder, supports the hypothesis that pathogenic AXIN2 variants increase risk as well. As the odds of a chance co-occurrence of a pathogenic AXIN2 variant and an olfactory neuroblastoma are so rare, it is worth exploring potential causation. We are building a clinical registry to expand understanding of the AXIN2 phenotype and request any clinicians caring for patients with pathogenic AXIN2 variants to contact us.

IDH2 Mutation Analysis in Undifferentiated and Poorly Differentiated Sinonasal Carcinomas for Diagnosis and Clinical Management

A large number of tumor types arise from the mucosa of the sinonasal cavities. Although presenting clinically distinct behavior, due to poorly differentiated histologic features, they can be difficult to classify correctly. Our aim was to investigate whether IDH2 and IDH1 mutations may be specific to a subset of undifferentiated and poorly differentiated sinonasal carcinomas. A total of 125 tumor samples of 7 different histologic subtypes were analyzed for IDH mutations by sequencing and mutant-specific immunohistochemistry, and the results were correlated to clinical and follow-up data. The highest incidence of IDH2 mutations occurred in sinonasal undifferentiated carcinoma, with 11/36 (31%) cases affected. However, also, 1/9 neuroendocrine carcinomas, 2/4 high-grade non-intestinal-type adenocarcinomas, and 1/8 poorly differentiated squamous cell carcinomas carried the IDH2 mutation, whereas 1/48 intestinal-type adenocarcinomas harbored an IDH1 mutation. Immunohistochemical analysis of mutant IDH1/2 produced a number of false-negative results, but also 1 false-positive tumor was found. Disease-specific survival was more favorable in IDH2-mutant versus wild-type cases. Our data suggest that IDH-mutant sinonasal cancers, independent of their histologic subtype, may represent a distinct tumor entity with less aggressive clinical behavior. Clinically, patients with these mutations may benefit from specific IDH-guided therapies.

Targeted 595-gene genomic profiling demonstrates low tumor mutational burden in olfactory neuroblastoma

BACKGROUND

Olfactory neuroblastoma (ONB) is a rare skull-base malignancy associated with delayed local recurrence. Treatment options in recurrent disease are few and unreliable. We undertook analysis of the ONB exome and immune environment in order to identify potential future immunotherapy treatment options.

METHODS

Retrospective chart review and next-generation targeted 595-gene genomic profiling was performed on a cohort of 14 ONB cases utilizing Tempus proprietary DNA and RNA sequencing technology. Tempus analysis provided a measurement of tumor mutational burden (TMB) and composition of the immune cell infiltrate present in tumor samples. Clinically relevant genomic alterations and associated targeted therapies were identified using cancer.gov and clinicaltrials.gov. TMB was tested by univariate analysis against clinical stage, pathologic grade, recurrence risk, and immune cell infiltration.

RESULTS

The mean age for the subjects was 50 years (range, 13 to 76 years) with a male:female ratio of 1:1. TMB for ONB samples ranged from 1.3 to 9.6 mutations/megabase (Mb) with mean of 3.8 mutations/Mb. Univariate analysis showed no association between TMB and tumor stage, pathologic grade, risk of recurrence, or immune cell infiltration. Genomic profile revealed that 6 of 13 tumors had genetic alterations with targeted therapies in clinical trials, whereas 1 tumor demonstrated KRAS Q61R mutation with U.S. Food and Drug Administration (FDA)-approved targeted therapies.

CONCLUSION

TMB is a novel biomarker guiding the classification of neoplasms in the emerging era of immunotherapy. The characterization of ONB as a low-TMB pathology contributes to the overall taxonomy of all cancers and suggests limited utility of immunotherapy treatment.

Integrated Multi-omic Analysis of Esthesioneuroblastomas Identifies Two Subgroups Linked to Cell Ontogeny

Esthesioneuroblastoma (ENB) is a rare cancer of the olfactory mucosa, with no established molecular stratification to date. We report similarities of ENB with tumors arising in the neural crest and perform integrative analysis of these tumors. We propose a molecular-based subtype classification of ENB as basal or neural, both of which have distinct pathological, transcriptomic, proteomic, and immune features. Among the basal subtype, we uncovered an IDH2 R172 mutant-enriched subgroup (∼35%) harboring a CpG island methylator phenotype reminiscent of IDH2 mutant gliomas. Compared with the basal ENB methylome, the neural ENB methylome shows genome-wide reprogramming with loss of DNA methylation at the enhancers of axonal guidance genes. Our study reveals insights into the molecular pathogenesis of ENB and provides classification information of potential therapeutic relevance.

Murine Oviductal High-Grade Serous Carcinomas Mirror the Genomic Alterations, Gene Expression Profiles, and Immune Microenvironment of Their Human Counterparts

Robust preclinical models of ovarian high-grade serous carcinoma (HGSC) are needed to advance our understanding of HGSC pathogenesis and to test novel strategies aimed at improving clinical outcomes for women with the disease. Genetically engineered mouse models of HGSC recapitulating the likely cell of origin (fallopian tube), underlying genetic defects, histology, and biologic behavior of human HGSCs have been developed. However, the degree to which the mouse tumors acquire the somatic genomic changes, gene expression profiles, and immune microenvironment that characterize human HGSCs remains unclear. We used integrated molecular characterization of oviductal HGSCs arising in the context of Brca1, Trp53, Rb1, and Nf1 (BPRN) inactivation to determine whether the mouse tumors recapitulate human HGSCs across multiple domains of molecular features. Targeted DNA sequencing showed the mouse BPRN tumors, but not endometrioid carcinoma-like tumors based on different genetic defects (e.g., Apc and Pten), acquire somatic mutations and widespread copy number alterations similar to those observed in human HGSCs. RNA sequencing showed the mouse HGSCs most closely resemble the so-called immunoreactive and mesenchymal subsets of human HGSCs. A combined immuno-genomic analysis demonstrated the immune microenvironment of BPRN tumors models key aspects of tumor-immune dynamics in the immunoreactive and mesenchymal subtypes of human HGSC, with enrichment of immunosuppressive cell subsets such as myeloid-derived suppressor cells and regulatory T cells. The findings further validate the BPRN model as a robust preclinical experimental platform to address current barriers to improved prevention, diagnosis, and treatment of this often lethal cancer. SIGNIFICANCE: The acquired gene mutations, broad genomic alterations, and gene expression and immune cell-tumor axis changes in a mouse model of oviductal serous carcinoma closely mirror those of human tubo-ovarian high-grade serous carcinoma.

Evaluating the prognostic potential of the Ki67 proliferation index and tumour-infiltrating lymphocytes in olfactory neuroblastoma

AIMS

Olfactory neuroblastomas (ONBs) are rare malignant tumours that arise in the nasal vault. To date, the Hyams grade remains the only widely used histological grading system. However, it is based only on morphological criteria, and has not been updated since 1988. The objective of this study was to explore the prognostic potential of the Ki67 proliferation index (PI) and tumour-infiltrating lymphocytes (TILs) in ONB.

METHODS AND RESULTS

A retrospective study was conducted on a bicentric series of 45 cases. The Ki67 PI was determined by counting at least 1000 nuclei on whole slides. TILs were evaluated with CD20, CD4 and CD8 immunohistochemical markers on whole slides. In this series, Hyams grades I, II, III and IV accounted for 13.4%, 44.4%, 20% and 22.2% of all cases, respectively. The Ki67 PI ranged from 1 to 93; the Ki67 PI was significantly higher in Hyams grade III-IV ONBs than in Hyams grade I-II ONBs (P < 0.0001). A Ki67 PI of ≥25 was associated with poorer survival (P = 0.02). TILs were present in both stromal and intratumoral compartments, but were located predominantly in the stromal component of the tumour. The numbers of intratumoral CD8+ cells/mm² and CD4+ cells/mm² were greater in high-grade ONBs than in low-grade ONBs (P = 0.0015 and P = 0.043, respectively). The numbers of T cells/mm² and B cells/mm² were not associated with survival, but a CD4/CD8 ratio of >2 was significantly associated with shorter survival (P = 0.04).

CONCLUSION

Our findings suggest that the Ki67 PI and TILs could be used as prognostic markers, as a potential alternative to the Hyams grade.

DNA methylation-based classification of sinonasal undifferentiated carcinoma

Sinonasal undifferentiated carcinoma (SNUC) is an aggressive malignancy harboring IDH2 R172 mutations in >80% cases. We explored the potential of genome-wide DNA methylation profiling to elucidate tumor biology and improve the diagnosis of sinonasal undifferentiated carcinoma and its histologic mimics. Forty-two cases, including sinonasal undifferentiated, large cell neuroendocrine, small cell neuroendocrine, and SMARCB1-deficient carcinomas and olfactory neuroblastoma, were profiled by Illumina Infinium Methylation EPIC array interrogating >850,000 CpG sites. The data were analyzed using a custom bioinformatics pipeline. IDH2 mutation status was determined by the targeted exome sequencing (MSK-IMPACT^TM) in most cases. H3K27 methylation level was assessed by the immunohistochemistry-based H-score. DNA methylation-based semi-supervised hierarchical clustering analysis segregated IDH2 mutants, mostly sinonasal undifferentiated (n = 10) and large cell neuroendocrine carcinomas (n = 4), from other sinonasal tumors, and formed a single cluster irrespective of the histologic type. t-distributed stochastic neighbor embedding dimensionality reduction analysis showed no overlap between IDH2 mutants, SMARCB1-deficient carcinoma and olfactory neuroblastoma. IDH2 mutants demonstrated a global methylation phenotype and an increase in repressive trimethylation of H3K27 in comparison to IDH2 wild-type tumors (p < 0.001). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed no difference in pathway activation between IDH2-mutated sinonasal undifferentiated and large cell neuroendocrine carcinomas. In comparison to SMARCB1-deficient, IDH2-mutated carcinomas were associated with better disease-free survival (p = 0.034) and lower propensity for lung metastasis (p = 0.002). ARID1A mutations were common in small cell neuroendocrine carcinoma but not among IDH2 mutants (3/3 versus 0/18 and p < 0.001). IDH2 mutations in sinonasal carcinomas induce a hypermethylator phenotype and define a molecular subgroup of tumors arising in this location. IDH2-mutated sinonasal undifferentiated carcinoma and large cell neuroendocrine carcinoma likely represent a phenotypic spectrum of the same entity, which is distinct from small cell neuroendocrine and SMARCB1-deficient sinonasal carcinomas. DNA methylation-based analysis of the sinonasal tumors has potential to improve the diagnostic accuracy and classification of tumors arising in this location.

Translational genomics of sinonasal cancers

The sinonasal cavities harbor a wide variety of histologically distinct cancers, the majority very aggressive with 5-year survival rates between 30-60% and local recurrence as the main cause of death. This is a complex anatomic area, close to structures such the eyes and the brain, which is of special relevance for surgery and postoperative radiotherapy. The low incidence of these rare tumors hampers accumulation of experience with diagnosis and clinical managment as well as knowledge on recurrent genetic aberrations or testing of new treatment strategies. However, recent years have seen a growing number of publications on genetic aberrations providing data that can aid or fine-tune classification and provide molecular targets for treatment with specific inhibitors. In addition, new sinonasal cancer models are created that enable preclinical testing of candidate inhibitor drugs. With more and more novel targeted therapies being developed, options for personalized treatment of sinonasal cancer patients are now opening up.

[Neuroendocrine neoplasms of the auditory, olfactory, and visual sensory organs]

Neuroendocrine neoplasms (NENs) are infrequent in sensory organs. There are well-differentiated neuroendocrine neoplasms that should be classified as neuroendocrine tumors, in analogy to their gastrointestinal counterparts, however the nomenclature is inconsistent. The best defined entities are neuroendocrine tumors in the middle ear and ectopic pituitary adenoma in the sphenoid region. Poorly differentiated NENs most often arise in the olfactory organ and nasal cavity that are represented by olfactory neuroblastomas and poorly differentiated neuroendocrine carcinomas. They have several mimickers such as the sinonasal undifferentiated carcinoma, poorly differentiated squamous cell carcinoma, mucosal malignant melanoma, rhabdomyosarcoma, Ewing sarcoma/primitive neuroectodermal tumor and non-Hodgkin lymphoma.

The role of a monoclonal antibody 11C8B1 as a diagnostic marker of IDH2-mutated sinonasal undifferentiated carcinoma

IDH2 R172 mutations occur in >80% sinonasal undifferentiated carcinomas ("SNUC") and ~80% of these are R172S and R172T variants. We examined the utility of the monoclonal antibody 11C8B1 to IDH2 R172S in IDH2 R172-mutated tumors to establish an immunohistochemistry protocol as a surrogate method for IDH2 R172S mutation detection. Eighty-eight formalin-fixed paraffin-embedded tumors including 42 sinonasal tumors and a variety of IDH1/2-mutated malignancies were tested by immunohistochemistry. The IDH1/2 mutation status was determined in 86 cases by a targeted massively parallel sequencing MSK-IMPACT^TM assay. Interestingly, monoclonal antibody 11C8B1 was reactive with all IDH2 R172S (N = 15) mutated tumors including 12 sinonasal carcinomas, 2 high-grade sarcomas and one intrahepatic cholangiocarcinoma, and with all R172T (N = 3) mutated sinonasal carcinomas displaying a distinct granular cytoplasmic labeling in all R172S/T mutated malignancies. 11C8B1 immunohistochemistry was also positive in 2 of 6 IDH1 R132S-mutated tumors, including one intrahepatic cholangiocarcinoma and one chondrosarcoma showing a smooth homogeneous cytoplasmic staining pattern. All IDH2 R172G/K/M/W (N = 22) and IDH1 132H/C/G/L (N = 15) mutated tumors, and all IDH1/2-wild-type tumors (N = 25), including a histologic variety of 23 sinonasal tumors, were immunonegative. Importantly, 11 sinonasal undifferentiated carcinomas (N = 14, 79%) and 3 (100%) high-grade neuroendocrine carcinomas, large cell type were 11C8B1 immunopositive. Literature search revealed a virtual absence of IDH2 R172 and IDH1 R132S mutations in >1000 cases of 8 different malignancies included in the differential diagnosis of sinonasal undifferentiated carcinoma. Our study suggests that positive IDH2 11C8B1 immunohistochemistry in sinonasal carcinomas would be highly predictive of the presence of IDH2 R172S/T mutations and could serve as a reliable adjunct diagnostic marker of sinonasal undifferentiated carcinomas in >70% cases.

Utility of adjuvant chemotherapy in patients receiving surgery and adjuvant radiotherapy for primary treatment of esthesioneuroblastoma

BACKGROUND

Past research established that surgery plus adjuvant radiotherapy (S + AR) improves overall survival (OS) in esthesioneuroblastoma (ENB). However, it is unknown if the addition of adjuvant chemotherapy (AC) further improves survival. The primary objective of this study was to compare survival among patients treated with S + AR alone to patients who underwent S + AR + AC.

METHODS

Retrospective review of patient records.

RESULTS

Thirty-eight patients met inclusion criteria for either S + AR or S + AR + AC treatment groups. The S + AR + AC group contained more patients with Kadish stage D disease, dural invasion, and positive histologic margins postsurgery. All S + AR + AC patients received platinum-based regimens, combined with etoposide in 67%. OS and recurrence-free survival did not differ between the two groups, even when restricting the analysis to patients with Kadish stages B and C disease.

CONCLUSION

Patients who received platinum-based AC did not exhibit improved survival compared to S + AR alone. Further investigation, preferably prospective, into the optimal use of systemic therapy in ENB is warranted.

DNA methylation-based reclassification of olfactory neuroblastoma

Olfactory neuroblastoma/esthesioneuroblastoma (ONB) is an uncommon neuroectodermal neoplasm thought to arise from the olfactory epithelium. Little is known about its molecular pathogenesis. For this study, a retrospective cohort of n = 66 tumor samples with the institutional diagnosis of ONB was analyzed by immunohistochemistry, genome-wide DNA methylation profiling, copy number analysis, and in a subset, next-generation panel sequencing of 560 tumor-associated genes. DNA methylation profiles were compared to those of relevant differential diagnoses of ONB. Unsupervised hierarchical clustering analysis of DNA methylation data revealed four subgroups among institutionally diagnosed ONB. The largest group (n = 42, 64%, Core ONB) presented with classical ONB histology and no overlap with other classes upon methylation profiling-based t-distributed stochastic neighbor embedding (t-SNE) analysis. A second DNA methylation group (n = 7, 11%) with CpG island methylator phenotype (CIMP) consisted of cases with strong expression of cytokeratin, no or scarce chromogranin A expression and IDH2 hotspot mutation in all cases. T-SNE analysis clustered these cases together with sinonasal carcinoma with IDH2 mutation. Four cases (6%) formed a small group characterized by an overall high level of DNA methylation, but without CIMP. The fourth group consisted of 13 cases that had heterogeneous DNA methylation profiles and strong cytokeratin expression in most cases. In t-SNE analysis, these cases mostly grouped among sinonasal adenocarcinoma, squamous cell carcinoma, and undifferentiated carcinoma. Copy number analysis indicated highly recurrent chromosomal changes among Core ONB with a high frequency of combined loss of chromosome 1-4, 8-10, and 12. NGS sequencing did not reveal highly recurrent mutations in ONB, with the only recurrently mutated genes being TP53 and DNMT3A. In conclusion, we demonstrate that institutionally diagnosed ONB are a heterogeneous group of tumors. Expression of cytokeratin, chromogranin A, the mutational status of IDH2 as well as DNA methylation patterns may greatly aid in the precise classification of ONB.

Sinonasal Neuroendocrine Neoplasms: Current Challenges and Advances in Diagnosis and Treatment, with a Focus on Olfactory Neuroblastoma

Sinonasal tumors with neuroendocrine differentiation form a group of rare heterogeneous neoplasms of neuroectodermal and epithelial origin, consisting of olfactory neuroblastomas and neuroendocrine carcinomas. Because the natural history and biological behavior of this group of tumors vary, the morphological diagnosis coupled with grading/staging is important for prognostication, and the approach to treatment and rehabilitation is multidisciplinary. The identification of molecular abnormalities underlying these tumors is critical to the development of specific targeted therapies and the design of clinical trials.

[Diagnostic and predictive molecular pathology of head and neck neoplasms]

As a result of some seminal observations as well as a consequence of increasing use of modern and innovative molecular diagnostic technologies, a variety of new genetic aberrations have been discovered in head and neck neoplasms of different anatomic locations and histogenetic origins. These advances resulted in the establishment of new molecularly defined disease entities. On the other hand, some of these new genetic biomarkers paved the way to potentially promising novel therapeutic opportunities. Diverse old (well known in other entities) and newly discovered translocations and gene fusions represent the leading subgroup of these genetic aberrations. They have been detected not only in malignant epithelial neoplasms (carcinomas) of the salivary glands, but also in carcinomas from other head and neck sites as well as diverse mesenchymal tumors. In addition to these gene fusions, several activating mutations (such as CTNNB1 in sinonasal glomangiopericytoma) as well as inactivating mutations or deletions (like SMARCB1 loss in sinonasal carcinomas) were detected as new molecular markers. In the present review we summarize the relevant molecular alterations in topographically and histopathologically distinct tumors of the head and neck region with emphasis on recently established molecular markers.

Comprehensive molecular profiling of advanced/metastatic olfactory neuroblastomas

Olfactory neuroblastoma (ONB) is a rare, locally aggressive, malignant neoplasm originating in the olfactory epithelium in the nasal vault. The recurrence rate of ONB remains high and there are no specific treatment guidelines for recurrent/metastatic ONBs. This study retrospectively evaluated 23 ONB samples profiled at Caris Life Sciences (Phoenix, Arizona) using DNA sequencing (Sanger/NGS [Illumina], n = 15) and gene fusions (Archer FusionPlex, n = 6), whole genome RNA microarray (HumanHT-12 v4 beadChip, Illumina, n = 4), gene copy number assays (chromogenic and fluorescent in situ hybridization), and immunohistochemistry. Mutations were detected in 63% ONBs including TP53, CTNNB1, EGFR, APC, cKIT, cMET, PDGFRA, CDH1, FH, and SMAD4 genes. Twenty-one genes were over-expressed and 19 genes under-expressed by microarray assay. Some of the upregulated genes included CD24, SCG2, and IGFBP-2. None of the cases harbored copy number variations of EGFR, HER2 and cMET genes, and no gene fusions were identified. Multiple protein biomarkers of potential response or resistance to classic chemotherapy drugs were identified, such as low ERCC1 [cisplatin sensitivity in 10/12], high TOPO1 [irinotecan sensitivity in 12/19], high TUBB3 [vincristine resistance in 13/14], and high MRP1 [multidrug resistance in 6/6 cases]. None of the cases (0/10) were positive for PD-L1 in tumor cells. Overexpression of pNTRK was observed in 67% (4/6) of the cases without underlying genetic alterations. Molecular alterations detected in our study (e.g., Wnt and cKIT/PDGFRA pathways) are potentially treatable using novel therapeutic approaches. Identified protein biomarkers of response or resistance to classic chemotherapy could be useful in optimizing existing chemotherapy treatment(s) in ONBs.