Lung neuroendocrine neoplasms: recent progress and persistent challenges

Treatment of RET/ALK comutated advanced lung large cell neuroendocrine carcinoma: a case report and literature review

The prognosis of advanced lung large-cell neuroendocrine carcinoma is poor, and the efficacy of targeted therapy is still being explored. A case of RET fusion mutation combined with ALK rearrangement positive advanced lung complex large cell neuroendocrine carcinoma was reported. The patient developed intrapulmonary and bone metastases 8 months after chemotherapy after lung cancer surgery, RET fusion mutations were detected by genetic testing, and intracranial progression occurred 1 year after pilatinib was applied. The comutation of RET and ALK was detected by genetic testing, and the pulmonary progression occurred 2 months after the application of aletinib, after being treated with pilatinib and aletinib, he progressed again in 9 months. We point out that large cell neuroendocrine carcinoma complex patients with RET gene mutation can benefit from targeted therapy, and when drug resistance is accompanied by ALK comutation, the patient can benefit from the treatment of the aletinib combined with pilatinib targeted therapy and the side effect is slight. At the same time, we further explore the resistance mechanism of targeted therapy in lung cancer.

Charting the Course: Insights into Neuroendocrine Tumor Dynamics in the United States

OBJECTIVE

To explore changing trends and characteristics in neuroendocrine tumors (NETs) epidemiology, focusing on demographics, clinical aspects, and survival, including the impact of social determinants of health (SDOH) on outcomes.

BACKGROUND

The escalating incidence and prevalence of NETs underscore the pressing need for updated epidemiologic data to reveal the evolving landscape of this condition. Access to current information is imperative for informing clinical strategies and public health initiatives targeting NETs.

METHODS

A retrospective, population-based study analyzed NET patient data from 1975 to 2020, using the Surveillance, Epidemiology, and End Results (SEER 8, 12, 18) program. We calculated annual age-adjusted incidence, prevalence, and 5-year overall survival (OS) rates. Survival trends from 2000 to 2019 were examined, employing the Fine-Gray model to evaluate cancer-specific mortality.

RESULTS

NETs' age-adjusted incidence rate quadrupled from 1.5 per 100,000 in 1975 to 6.0 per 100,000 in 2020. A decline in incidence occurred from 6.8 per 100,000 in 2019 to 6.0 per 100,000 in 2020. All-cause survival multivariable analysis demonstrated high grade (HR: 2.95, 95% CI: 2.63-3.09, P <0.001), single patients (HR: 1.49, 95% CI: 1.45-1.54, P <0.001), and Black patients (HR: 1.17, 95% CI:1.13-1.22, P <0.001) all had worse survival than their controls.

CONCLUSIONS

Our study shows a steady increase in NETs incidence until 2019, with a decline in 2020. Understanding the reasons behind this trend is vital for improved management and public health planning. Further research should focus on the factors driving these changes to enhance our understanding of NET epidemiology.

Epstein-Barr virus-positive small cell neuroendocrine carcinoma of the nasopharynx: A clinicopathologic study of 7 cases and literature review

Epstein-Barr virus (EBV)-positive small cell neuroendocrine carcinoma (NEC) of the nasopharynx is a rare entity with poorly characterized clinicopathological and prognostic features. In this study, seven cases of EBV-positive nasopharyngeal small cell NEC will be compared to 6 EBV-negative cases of nasopharyngeal small cell NEC. The overall EBV-positive rate, defined by EBV-encoded small RNAs (EBERs) in situ hybridization of nasopharyngeal small cell NEC, was 53.8 % (7/13). The patients' age ranged from 38 to 73 years, with a median age of 56 years. There was a large preponderance of males, with a male-to-female ratio of 6:1. In the present study, EBV-positive nasopharyngeal small cell NEC had a significantly higher expression of POU2F3 (85.7 %, 6/7) than EBV-negative nasopharyngeal small cell NEC (16.7 %, 1/6). RNA sequencing revealed that EBV-positive nasopharyngeal small cell NEC was distinct from EBV-negative nasopharyngeal small cell NEC in the control group. There was no statistically significant difference in overall survival between patients with EBV-positive and EBV-negative nasopharyngeal small cell NEC in the present cohort. These findings suggest that EBV-positive nasopharyngeal small cell NEC may be closely associated with POU2F3. In addition, POU2F3 and ASCL1 may play important roles in the tumorigenesis of EBV-positive nasopharyngeal small cell NEC.

Myc family proteins: Molecular drivers of tumorigenesis and resistance in neuroendocrine tumors

Neuroendocrine cancers are a diverse and poorly understood collection of malignancies derived from neuroendocrine cells throughout the body. These cancers uniquely exhibit properties of both the nervous and endocrine systems. Only a limited number of genetic driver mutations have been identified in neuroendocrine cancers, however the mechanisms of how these genetic aberrations alter tumor biology remain elusive. Recent studies have implicated the MYC family of transcription factors as important oncogenic factors in neuroendocrine tumors. We take a systematic approach to understand the roles of the MYC family (c-MYC, n-MYC, l-MYC) in the tumorigenesis of neuroendocrine cancers of the lung, GI tract, pancreas, kidney, prostate, pediatric neuroblastoma, and adrenal glands. Reflecting the complexity of neuroendocrine cancers, we highlight the roles of the MYC family in deregulating the cell cycle and transcriptional networks, invoking cellular plasticity, affecting proliferation capacity, aiding in chromatin remodeling, angiogenesis, metabolic changes, and resistance mechanisms. Depicting the diversity of neuroendocrine cancers, we suggest new approaches in understanding the underlying tumorigenic processes of neuroendocrine cancers from the perspective of MYC.

Lung Carcinoid Tumors With Potentially Actionable Genomic Alterations and Responses to Targeted Therapies

BACKGROUND

Effective treatments for patients with advanced lung carcinoids remain limited. The prevalence of potentially actionable genomic alterations (AGAs) among lung carcinoids is not well-understood.

MATERIALS AND METHODS

Lung carcinoids submitted for next-generation sequencing (NGS) at a Clinical Laboratory Improvement Amendments (CLIA)-certified genomics laboratory from September 2013 to March 2024 were retrospectively investigated to determine prevalence of AGAs. We evaluated outcomes with genotype-matched targeted therapies in patients with advanced lung carcinoids with AGAs identified across 3 institutions and comprehensive literature search.

RESULTS

Among 321 cases of lung carcinoids profiled by NGS, 8 (2.5%) harbored potential AGAs (4 [1.2%] with commercially available targeted therapies), including KRAS mutations (n = 4, 1.2%: G12C, G12D, G12R, G12V), ALK fusions (n = 2, 0.6%), BRAF D594N (n = 1, 0.3%), and RET fusion (n = 1, 0.3%). None of the 24 typical carcinoids harbored an AGA. Collectively across these database-identified patients, our multi-institutional cohort, and literature review, we identified 36 cases of lung carcinoids with potential AGAs (24 with commercially available targeted therapies), predominantly comprising fusions of ALK (n = 14), RET (n = 5), and NTRK (n = 2). Of 27 with known disease stage, 19 had stage 4 disease, and 13 (68.4%) had outcomes reported following targeted therapies. Median treatment duration was 12.0 months (95% CI: 6.7-16.0). Median progression-free survival (PFS) was 10.6 months (95% CI: 6.7-16.0) across all targeted therapy lines and 14.0 months (95% CI: 1.3-NA) with first-line targeted therapies. Objective response rate with at least one targeted therapy was 61.5%.

CONCLUSIONS

Patients with advanced lung carcinoids harboring AGAs can derive meaningful benefit from genotype-matched targeted therapies, highlighting potential role for NGS in patients with advanced carcinoids.

Basic science and translational implications of current knowledge on neuroendocrine tumors

Neuroendocrine tumors (NETs) are a diverse group of malignancies that can occur in various organs, with a notable prevalence in the lungs and gastrointestinal tract, which are the focus of this Review. Although NETs are rare in individual organs, their incidence has increased over recent decades, highlighting the urgent need for current classification systems to evolve by incorporating recent advances in the understanding of NET biology. Several omics studies have revealed molecular subtypes, which, when integrated into existing classification frameworks, may provide more clinically relevant insights for patients with NETs. This Review examines recent progress in elucidating the biology of NETs, with a particular emphasis on the tumor microenvironment and cells of origin. The existence of different cells of origin, which may contribute to distinct molecular groups, along with profiles of immune infiltration - despite being generally low - could explain the emergence of more aggressive cases and the potential for metastatic progression. Given the molecular heterogeneity of NETs and the diversity of their microenvironments and different cells of origin, there is an urgent need to develop morphomolecular classification systems. Such systems would make it possible to better characterize tumor progression, identify new therapeutic targets, and, ultimately, guide the development of personalized therapies.

Oncocytic and spindle cell typical carcinoids of lung: different immunophenotype and biological behavior

Pulmonary typical carcinoids (TCs) are uncommon, well-differentiated neuroendocrine tumors of the lung that do not exhibit necrosis and have fewer than two mitoses per 2 mm2, as defined by the current World Health Organization classifications. Despite their low-grade status and favorable prognostic impact, the protein expression profile and morphological characteristics associated with tumor progression and metastatic spread remain largely unidentified. Oncocytic and spindle cell histological variants are acknowledged for their role in differential diagnosis, though their clinical significance remains a topic of debate. We centrally reviewed a multicenter series of 297 TCs to identify cases of oncocytic and spindle cell variants. We examined associations with clinicopathological features and immunohistochemical markers (orthopedia homeobox protein, thyroid transcription factor 1, mammalian achaete-scute homologue 1, somatostatin receptor 2A, Ki-67, anti-mitochondria, and S100); these data were further related to disease-free survival (DFS), overall survival, and cancer-specific survival (CSS). Our analysis identified oncocytic TCs (n = 36, 12.1%), spindle cell TCs (n = 55, 18.5%), and ordinary TCs, defined as those without either variant or with variants that were not prominent (n = 206, 69.4%). Interestingly, ordinary tumors were associated with a higher number of tumor-related deaths (p = 0.01) compared to the other histological variants. Additionally, patients with spindle cell morphology had longer CSS compared to those with ordinary morphology (p = 0.04). Parameters such as histological variant, age, tumor stage, and Ki-67 were significantly linked to DFS on multivariable analysis, even after accounting for differences between centers. In conclusion, oncocytic, spindle cell, and ordinary TCs are linked to distinct clinicopathological characteristics and exhibit varying clinical outcomes.

Neuroendocrine differentiation and serotonin expression in oesophageal adenocarcinomas after neoadjuvant therapy: correlation with clinicopathological features and outcome

AIMS

Oesophageal adenocarcinoma (EAC) is a glandular or mucinous epithelial malignancy that can show immunohistochemical evidence of neuroendocrine differentiation (NED) and express the hormone serotonin. The objective of this study was to correlate the presence of NED and serotonin with clinicopathological characteristics and patient outcome after neoadjuvant chemoradiation.

METHODS AND RESULTS

A retrospective cohort of patients treated between 2002 and 2021 was established and included 218 oesophagectomy specimens with residual tumour. Representative full-face sections of tumour were stained for synaptophysin, chromogranin-A and serotonin by immunohistochemistry, and staining results were correlated with disease-free survival (DFS) and overall survival (OS). In total, 129 (59%) tumours showed evidence of NED, defined as immunohistochemical expression of synaptophysin or chromogranin-A, while 40 (18%) showed evidence of NED and expressed serotonin. Patients with neuroendocrine-positive tumours had significantly shorter median OS compared to those with neuroendocrine-negative tumours (22.5 versus 48.8 months, P = 0.006), but similar median DFS (13.3 versus 17.8 months, P = 0.34). Using Cox regression, the association between NED and OS was significant in univariate [hazard ratio (HR) = 1.68, 95% confidence interval (CI) = 1.16-2.45] and multivariate (HR = 1.65, 95% CI = 1.08-2.52) analysis. Patients with serotonin-expressing tumours had similar median OS (21.7 versus 25.9 months, P = 0.24) and DFS (7.3 versus 15.6 months, P = 0.12) compared to those with NED but lacking serotonin. Using Cox regression, serotonin expression was associated with reduced OS in univariate (HR = 1.62, 95% CI = 1.06-2.47) but not multivariate (HR = 1.03, 95% CI = 0.64-1.65) analysis.

CONCLUSIONS

Our findings support NED as independent predictor of OS in EAC after neoadjuvant chemoradiation. While a subset of tumours with NED expressed serotonin, this did not provide additional prognostic information.

Framework for the Pathology Workup of Metastatic Castration-Resistant Prostate Cancer Biopsies

Lineage plasticity and histologic transformation from prostate adenocarcinoma to neuroendocrine (NE) prostate cancer (NEPC) occur in up to 15% to 20% of patients with castration-resistant prostate cancer (CRPC) as a mechanism of treatment resistance and are associated with aggressive disease and poor prognosis. NEPC tumors typically display small cell carcinoma morphology with loss of androgen receptor (AR) expression and gain of NE lineage markers. However, there is a spectrum of phenotypes that are observed during the lineage plasticity process, and the clinical significance of mixed histologies or those that co-express AR and NE markers or lack all markers is not well defined. Translational research studies investigating NEPC have used variable definitions, making clinical trial design challenging. In this manuscript, we discuss the diagnostic workup of metastatic biopsies to help guide the reproducible classification of phenotypic CRPC subtypes. We recommend classifying CRPC tumors based on histomorphology (adenocarcinoma, small cell carcinoma, poorly differentiated carcinoma, other morphologic variant, or mixed morphology) and IHC markers with a priority for AR, NK3 homeobox 1, insulinoma-associated protein 1, synaptophysin, and cell proliferation based on Ki-67 positivity, with additional markers to be considered based on the clinical context. Ultimately, a unified workup of metastatic CRPC biopsies can improve clinical trial design and eventually practice.

Artificial intelligence for diagnosis and predictive biomarkers in Non-Small cell lung cancer Patients: New promises but also new hurdles for the pathologist

The rapid development of artificial intelligence (AI) based tools in pathology laboratories has brought forward unlimited opportunities for pathologists. Promising AI applications used for accomplishing diagnostic, prognostic and predictive tasks are being developed at a high pace. This is notably true in thoracic oncology, given the significant and rapid therapeutic progress made recently for lung cancer patients. Advances have been based on drugs targeting molecular alterations, immunotherapies, and, more recently antibody-drug conjugates which are soon to be introduced. For over a decade, many proof-of-concept studies have explored the use of AI algorithms in thoracic oncology to improve lung cancer patient care. However, despite the enthusiasm in this domain, the set-up and use of AI algorithms in daily practice of thoracic pathologists has not been operative until now, due to several constraints. The purpose of this review is to describe the potential but also the current barriers of AI applications in routine thoracic pathology for non-small cell lung cancer patient care and to suggest practical solutions for rapid future implementation.

Chromothripsis-Mediated Small Cell Lung Carcinoma

Small cell lung carcinoma (SCLC) is a highly aggressive malignancy that is typically associated with tobacco exposure and inactivation of RB1 and TP53 genes. Here, we performed detailed clinicopathologic, genomic, and transcriptomic profiling of an atypical subset of SCLC that lacked RB1 and TP53 co-inactivation and arose in never/light smokers. We found that most cases were associated with chromothripsis-massive, localized chromosome shattering-recurrently involving chromosome 11 or 12 and resulting in extrachromosomal amplification of CCND1 or co-amplification of CCND2/CDK4/MDM2, respectively. Uniquely, these clinically aggressive tumors exhibited genomic and pathologic links to pulmonary carcinoids, suggesting a previously uncharacterized mode of SCLC pathogenesis via transformation from lower-grade neuroendocrine tumors or their progenitors. Conversely, SCLC in never-smokers harboring inactivated RB1 and TP53 exhibited hallmarks of adenocarcinoma-to-SCLC derivation, supporting two distinct pathways of plasticity-mediated pathogenesis of SCLC in never-smokers. Significance: Here, we provide the first detailed description of a unique SCLC subset lacking RB1/TP53 alterations and identify extensive chromothripsis and pathogenetic links to pulmonary carcinoids as its hallmark features. This work defines atypical SCLC as a novel entity among lung cancers, highlighting its exceptional histogenesis, clinicopathologic characteristics, and therapeutic vulnerabilities. See related commentary by Nadeem and Drapkin, p. 8.

TERT Expression and Clinical Outcome in Pulmonary Carcinoids

PURPOSE

The clinical course of pulmonary carcinoids ranges from indolent to fatal disease, suggesting that specific molecular alterations drive progression toward the fully malignant state. A similar spectrum of clinical phenotypes occurs in pediatric neuroblastoma, in which activation of telomerase reverse transcriptase (TERT) is decisive in determining the course of disease. We therefore investigated whether TERT expression defines the clinical fate of patients with pulmonary carcinoid.

METHODS

TERT expression was examined by RNA sequencing in a test cohort and a validation cohort of pulmonary carcinoids (n = 88 and n = 105, respectively). A natural TERT expression cutoff was determined in the test cohort on the basis of the distribution of TERT expression, and its prognostic value was assessed by Kaplan-Meier survival estimates and multivariable analyses. Telomerase activity was validated by telomere repeat amplification protocol assay.

RESULTS

Similar to neuroblastoma, TERT expression exhibited a bimodal distribution in pulmonary carcinoids, separating tumors into TERT-high and TERT-low subgroups. A natural TERT cutoff discriminated unfavorable from favorable clinical courses with high accuracy both in the test cohort (5-year overall survival [OS], 0.547 ± 0.132 v 1.0; P < .001) and the validation cohort (5-year OS, 0.788 ± 0.063 v 0.913 ± 0.048; P < .001). In line with these findings, telomerase activity was largely absent in TERT-low tumors, whereas it was readily detectable in TERT-high carcinoids. In multivariable analysis considering TERT expression, histology (typical v atypical carcinoid), and stage (≤IIA v ≥IIB), high TERT expression was an independent prognostic marker for poor survival, with a hazard ratio of 5.243 (95% CI, 1.943 to 14.148; P = .001).

CONCLUSION

Our data demonstrate that high TERT expression defines clinically aggressive pulmonary carcinoids with fatal outcome, similar to neuroblastoma, indicating that activation of TERT may be a defining feature of lethal cancers.

Neuroendocrine tumor discovered in a teenager following asthma misdiagnosis

Although relatively rare, neuroendocrine tumors (NETs) represent the most common type of endobronchial tumors in pediatric patients. Their clinical presentation lacks specificity, often leading to delayed diagnosis due to limited clinical suspicion. Mainly classified as low-grade malignant tumors (grade 1), they typically demonstrate favorable outcomes following surgical removal. However, local recurrence and/or metastases may occur in both low- and high-grade NET. We present the case of a 17-year-old girl initially misdiagnosed with asthma, later found to have a low-grade NET obstructing the left main bronchus. Surgical resection enabled complete tumor removal, and subsequent follow-up confirmed the postsurgical recovery. This case emphasizes the importance of familiarizing pediatricians and GP with the need for chest X-rays in all initial asthma diagnosis in order to eliminate differential diagnoses such as bronchial NET. This underscores the importance of a prompt diagnosis and follow-up care in similar cases.

Protein kinase D2-Aurora kinase A-ERK1/2 signalling axis drives neuroendocrine differentiation of epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is deadliest gynecological malignancy with poor prognosis and patient survival. Despite development of several therapeutic interventions such as poly-ADP ribose polymerase (PARP) inhibitors, EOC remains unmanageable and discovery of novel early detection biomarkers and treatment targets are highly warranted. Although neuroendocrine differentiation (NED) is implicated in different human cancers including prostate adenocarcinoma and lung cancer, mechanistic studies concerning NED of epithelial ovarian cancer are lacking. We report that Aurora kinase A drives NED of epithelial ovarian cancer in an ERK1/2-dependent manner and pharmacological and genetic inhibition of Aurora kinase A suppress NED of ovarian cancer. Moreover, we demonstrate that protein kinase D2 positively regulated Aurora kinase A to drive NED. Overexpression of catalytically active PKD2 drives NED and collectively, PKD2 cross talks with Aurora kinase A/ERK1/2 signalling axis to positively regulate NED of EOC. PKD2/Aurora kinase A/ERK1/2 signalling axis is a novel therapeutic target against neuroendocrine differentiated EOC.

Optimizing Endoscopic Respiratory Diagnostics with Cytology: An Update on Touch Imprints with a Comparative Literature Review

Background: Major diagnostic and therapeutic changes led to the implementation of the 'lung cancer diagnosis in small biopsies and cytology specimens' concept in the WHO Classification of Tumours of the Lung, Pleura, Thymus and Heart in 2015. Touch imprints are an established technique in cytology that provides a rapid and minimally invasive method for morphological diagnoses of clinical specimens, accurate subtyping, and molecular characterizations of malignancies. The extended diagnostic requirements from the increasingly limited material provided by minimally invasive biopsy techniques pose major challenges for pathology. Recognizing the relevant features and potential pitfalls is essential for cytologists to avoid misinterpretation. Materials and Methods: A retrospective analysis of endoscopic and surgical biopsy diagnostics was performed on 717 patients (303 women and 414 men; average age of 66.9 years) with clinically suspicious tumor findings at the LungenClinic Grosshansdorf in 2020. A total of 1363 cytological samples were obtained pre-therapeutically from 986 distinct biopsies covering 330 surgically and 656 endoscopically examined pulmonary, mediastinal, and bronchial regions. These samples were then compared with the histological diagnoses that were critical for determining the final therapy. Results: Out of a total of 656 endoscopically examined cases, 322 were classified as malignant, 308 as benign, and 26 as undetermined. While touch imprints and histological analysis separately achieved specificity values of 95.4% and 98.8%, both methods showed sensitivity values of 82.1% and 86.5%, respectively. In contrast, combining the two methods improved the sensitivity by 8 percentage points to 94.6%. Out of 330 cases of surgically examined samples, 137 were malignant, 190 were benign, and 3 were undetermined. The specificity of the morphological examinations for these samples was comparably high at 97.9% and 100%, respectively. In this surgical setting, touch imprints alone achieved a sensitivity of 75.9% (n = 104/137 cases), with a specificity of 97.9% (n = 186/190 cases). The outcome of the histological approach alone and in combination with touch imprints reached a sensitivity of 96.4% (n = 132/137 cases). Conclusions: Cytology and histology achieved comparably high sensitivity and specificity values on small biopsies. Under optimal conditions for morphological analysis in a surgical setting, the sensitivity of cytology for detecting malignant tumors was only 6 percentage points lower compared with the clinical endoscopic setting. A combined approach of cytologic-histologic evaluation for endoscopically examined specimens significantly increased the sensitivity by approximately 8% compared with the surgical setting (p < 0.003).

Delta-like ligand 3 (DLL3) landscape in pulmonary and extra-pulmonary neuroendocrine neoplasms

Delta-like Ligand 3 (DLL3) targeting therapies are promising in small cell lung cancer (SCLC) treatment. However, DLL3 expression in SCLC and other neuroendocrine neoplasms (NEN) is heterogeneous and not well characterized. We describe the landscape of DLL3 at the mRNA and protein levels across SCLC, large cell neuroendocrine carcinoma (LCNEC), and non-small cell lung cancer. Additionally, we explore its expression in extra-pulmonary NEN (EP-NEN) using a standardized DLL3 IHC assay. DLL3 expression is enriched in SCLC, LCNEC along with combined histology lung cancers. Moreover, we find a wide range of DLL3 expression in high-grade EP-NEN. We describe heterogenous DLL3 expression not only in SCLC but also in different NEN types. This comprehensive characterization of DLL3 can help guide future clinical trial design targeting DLL3 in NEN including LCNEC and EP-NEN that are lacking standard of care treatment options.

RepID as a potential biomarker and therapeutic target for lung neuroendocrine tumor

Neuroendocrine tumor (NET) is a rare malignant tumor, notably small cell lung cancer (SCLC), a type of lung neuroendocrine tumor, which has a survival rate of less than 7%. Although various biomarkers including CHGA (Chromogranin A), INSM1 (Insulinoma-associated protein 1), and SYP (Synaptophysin) are extensively used for the diagnostic testing of NET, their diverse specificities and sensitivities are acknowledged as limitations. Here, we demonstrate that RepID (Replication initiation determinant protein), a component of CRL4 (Cullin-RING ubiquitin E3 ligase 4), holds promise as a biomarker for identifying NET and SCLC. Analysis of the Cancer Cell Line Encyclopedia (CCLE) via the CellMinerCDB portal reveals a high correlation between RepID transcript levels and mRNA expression of NE signature genes. Additionally, RepID protein is highly expressed in SCLC patient tissues and a subset of SCLC cell lines. Viability analysis following treatment with pevonedistat and SZL-P1-41 in SCLC cell lines and human SCLC-organoid models indicates that RepID expression determines the sensitivity to CRL-targeting anti-cancer drugs. These findings suggest that RepID represents a novel biomarker for NET and SCLC, and insights from RepID research in these cancers could lead to innovative therapeutic strategies.

Natural Killer Cells in Cancers of Respiratory System and Their Applications in Therapeutic Approaches

BACKGROUND

Cancer is still regarded as a major worldwide health issue due to its high health and socioeconomic burden. Currently, lung cancer is the most common cause of cancer-related fatalities globally. Additionally, mesotheliomas and other cancers of the respiratory system, including those of the trachea, larynx, and bronchi, are also posing a significant health threat. Natural killer (NK) cells are lymphocytes of the innate immune system involved in response against cancer.

OBJECTIVE

This review discussed recent findings in the context of NK cell activity in the immune surveillance of respiratory system cancers and NK cell-based treatments to combat those malignancies.

RESULTS

The presence of natural killer cells in the tumor microenvironment is shown to be associated with a higher survival rate in patients with various malignancies. However, cancerous cells benefit from several mechanisms to evade natural killer cell-mediated cytotoxicity, including reduced major histocompatibility complex I expression, shedding of ligands, upregulation of inhibitory receptors, and release of soluble factors. Using NK cells to design therapeutic approaches may enhance antitumor immunity and improve clinical outcomes. Clinical trials investigating the use of natural killer cells in combination with cytokine stimulation or immune checkpoint inhibitors have exhibited promising results in various respiratory system malignancies.

CONCLUSION

Respiratory system cancers present significant health challenges worldwide, and while NK cells play a crucial role in tumor surveillance, tumors often evade NK cell responses through various mechanisms. Advances in NK cell-based therapies, including CAR-NK cells, immune checkpoint inhibitors, and cytokine stimulation, have shown promising outcomes in tackling these tactics. However, challenges such as the immunosuppressive tumor microenvironment persist. Ongoing research is crucial to improve NK cell therapies by targeting autophagy, modulating miRNAs, and developing combinatorial approaches to enhance treatment efficacy for respiratory cancers.

[Neuroendocrine carcinomas of the gastrointestinal tract : Morphology, molecular pathology, cellular origin]

Neuroendocrine carcinomas (NEC) are poorly differentiated neuroendocrine neoplasms that can occur ubiquitously in the mucosa-bearing organs of the gastrointestinal tract. Based on their morphology, they are classified into large cell (LCNEC) and small cell NEC (SCNEC). The most common form of mixed differentiation is the combination with an adenocarcinoma, referred to as mixed adenoneuroendocrine carcinoma (MANEC). NEC/MANEC exhibit a significantly poorer prognosis than the adenocarcinomas of their respective primary sites, which is inextricably linked to their typical histomorphology. Adenocarcinomas with aberrant expression of neuroendocrine markers do not show a worse clinical course. Molecularly, NEC/MANEC have a profile comparable to the adenocarcinomas of their site of origin and a profile divergent from neuroendocrine tumors. Analyses of gastric NEC/MANEC have shown frequent MYC amplifications, which are reflected in MYC signatures in various transcriptome analyses.The cellular origin of NEC remains a subject of controversial discussion. New insights are provided by a MYC-driven, genetically modified mouse model that led to the development of large gastric tumors. These tumors were histologically identified as LCNEC and were accompanied by both neuroendocrine and non-neuroendocrine precursor lesions. Using immunofluorescence, a derivation from resident neuroendocrine cells in the gastric corpus was demonstrated, suggesting that at least a portion of LCNEC may originate directly from neuroendocrine cells.

YAP1 Status Defines Two Intrinsic Subtypes of LCNEC with Distinct Molecular Features and Therapeutic Vulnerabilities

PURPOSE

Large cell neuroendocrine carcinoma (LCNEC) is a high-grade neuroendocrine malignancy that, like small cell lung cancer (SCLC), is associated with the absence of druggable oncogenic drivers and dismal prognosis. In contrast to SCLC, however, there is little evidence to guide optimal treatment strategies, which are often adapted from SCLC and non-small cell lung cancer approaches.

EXPERIMENTAL DESIGN

To better define the biology of LCNEC, we analyzed cell line and patient genomic data and performed IHC and single-cell RNA sequencing of core needle biopsies from patients with LCNEC and preclinical models.

RESULTS

In this study, we demonstrate that the presence or absence of YAP1 distinguishes two subsets of LCNEC. The YAP1-high subset is mesenchymal and inflamed and is characterized, alongside TP53 mutations, by co-occurring alterations in CDKN2A/B and SMARCA4. Therapeutically, the YAP1-high subset demonstrates vulnerability to MEK- and AXL-targeting strategies, including a novel preclinical AXL chimeric antigen receptor-expressing T cell. Meanwhile, the YAP1-low subset is epithelial and immune-cold and more commonly features TP53 and RB1 co-mutations, similar to those observed in pure SCLC. Notably, the YAP1-low subset is also characterized by the expression of SCLC subtype-defining transcription factors, especially ASCL1 and NEUROD1, and as expected, given its transcriptional similarities to SCLC, exhibits putative vulnerabilities reminiscent of SCLC, including delta-like ligand 3 and CD56 targeting, as is with novel preclinical delta-like ligand 3 and CD56 chimeric antigen receptor-expressing T cells, and DNA damage repair inhibition.

CONCLUSIONS

YAP1 defines distinct subsets of LCNEC with unique biology. These findings highlight the potential for YAP1 to guide personalized treatment strategies for LCNEC.

Enhancer landscape of lung neuroendocrine tumors reveals regulatory and developmental signatures with potential theranostic implications

Well-differentiated low-grade lung neuroendocrine tumors (lung carcinoids or LNETs) are histopathologically classified as typical and atypical LNETs, but each subtype is still heterogeneous at both the molecular level and its clinical manifestation. Here, we report genome-wide profiles of primary LNETs' cis-regulatory elements by H3K27ac ChIP-seq with matching RNA-seq profiles. Analysis of these regulatory landscapes revealed three regulatory subtypes, independent of the typical/atypical classification. We identified unique differentiation signals that delineate each subtype. The "proneuronal" subtype emerges under the influence of ASCL1, SOX4, and TCF4 transcription factors, embodying a pronounced proneuronal signature. The "luminal-like" subtype is characterized by gain of acetylation at markers of luminal cells and GATA2 activation and loss of LRP5 and OTP. The "HNF+" subtype is characterized by a robust enhancer landscape driven by HNF1A, HNF4A, and FOXA3, with notable acetylation and expression of FGF signaling genes, especially FGFR3 and FGFR4, pivotal components of the FGF pathway. Our findings not only deepen the understanding of LNETs' regulatory and developmental diversity but also spotlight the HNF+ subtype's reliance on FGFR signaling. We demonstrate that targeting this pathway with FGF inhibitors curtails tumor growth both in vitro and in xenograft models, unveiling a potential vulnerability and paving the way for targeted therapies. Overall, our work provides an important resource for studying LNETs to reveal regulatory networks, differentiation signals, and therapeutically relevant dependencies.

Differential NEUROD1, ASCL1, and POU2F3 Expression Defines Molecular Subsets of Bladder Small Cell/Neuroendocrine Carcinoma With Prognostic Implications

Small cell carcinomas (SMC) of the lung are now molecularly classified based on the expression of transcriptional regulators (NEUROD1, ASCL1, POU2F3, and YAP1) and DLL3, which has emerged as an investigational therapeutic target. PLCG2 has been shown to identify a distinct subpopulation of lung SMC with stem cell-like and prometastasis features and poor prognosis. We analyzed the expression of these novel neuroendocrine markers and their association with traditional neuroendocrine markers and patient outcomes in a cohort of bladder neuroendocrine carcinoma (NEC) consisting of 103 SMC and 19 large cell NEC (LCNEC) assembled in tissue microarrays. Coexpression patterns were assessed and integrated with detailed clinical annotation including overall (OS) and recurrence-free survival (RFS) and response to neoadjuvant/adjuvant chemotherapy. We identified 5 distinct molecular subtypes in bladder SMC based on the expression of ASCL1, NEUROD1, and POU2F3: ASCL1+/NEUROD1- (n = 33; 34%), ASCL1- /NEUROD1+ (n = 21; 21%), ASCL1+/NEUROD1+ (n = 17; 17%), POU2F3+ (n = 22, 22%), and ASCL1- /NEUROD1- /POU2F3- (n = 5, 5%). POU2F3+ tumors were mutually exclusive with those expressing ASCL1 and NEUROD1 and exhibited lower expression of traditional neuroendocrine markers. PLCG2 expression was noted in 33 tumors (32%) and was highly correlated with POU2F3 expression (P < .001). DLL3 expression was high in both SMC (n = 72, 82%) and LCNEC (n = 11, 85%). YAP1 expression was enriched in nonneuroendocrine components and negatively correlated with all neuroendocrine markers. In patients without metastatic disease who underwent radical cystectomy, PLCG2+ or POU2F3+ tumors had shorter RFS and OS (P < .05), but their expression was not associated with metastasis status or response to neoadjuvant/adjuvant chemotherapy. In conclusion, the NEC of the bladder can be divided into distinct molecular subtypes based on the expression of ASCL1, NEUROD1, and POU2F3. POU2F3-expressing tumors represent an ASCL1/NEUROD1-negative subset of bladder NEC characterized by lower expression of traditional neuroendocrine markers. Marker expression patterns were similar in SMC and LCNEC. Expression of PLCG2 and POU2F3 was associated with shorter RFS and OS. DLL3 was expressed at high levels in both SMC and LCNEC of the bladder, nominating it as a potential therapeutic target.

Head-to-head: Should Ki67 proliferation index be included in the formal classification of pulmonary neuroendocrine neoplasms?

The reporting of lung neuroendocrine neoplasms (NENs) according to the 2021 World Health Organisation (WHO) is based on mitotic count per 2 mm2, necrosis assessment and a constellation of cytological and immunohistochemical details. Accordingly, typical carcinoid and atypical carcinoid are low- to intermediate-grade neuroendocrine tumours (NETs), while large-cell neuroendocrine carcinoma (NEC) and small-cell lung carcinoma are high-grade NECs. In small-sized diagnostic material (cytology and biopsy), the noncommittal term of carcinoid tumour/NET not otherwise specified (NOS) and metastatic carcinoid NOS have been introduced with regard to primary and metastatic diagnostic settings, respectively. Ki-67 antigen, a well-known marker of cell proliferation, has been included in the WHO classification as a non-essential but desirable criterion, especially to distinguish NETs from high-grade NECs and to delineate the provisional category of carcinoid tumours/NETs with elevated mitotic counts (> 10 mitoses per mm2) and/or Ki-67 proliferation index (≥ 30%). However, a wider use of this marker in the spectrum of lung NENs continues to be highly reported and debated, thus witnessing a never-subsided attention. Therefore, the arguments for and against incorporating Ki-67 in the classification and clinical practice of these neoplasms are discussed herein in detail.

Molecular subtypes and prognostic factors of lung large cell neuroendocrine carcinoma

Background

Lung large cell neuroendocrine carcinoma (LCNEC) is an aggressive disease with poor prognosis and short-term survival, which lacks effective prognostic indicators. The study aims to investigate the molecular subtypes and prognostic markers of lung LCNEC.

Methods

Patients diagnosed with lung LCNEC at Sun Yat-sen University Cancer Center (SYSUCC) between November 2007 and January 2021 were screened. Baseline clinical data were collected and routine blood indexes including lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) were calculated. Immunohistochemistry (IHC) of ASCL1, NEUROD1, POU2F3, YAP1 were done to perform molecular subtyping, while CD56, Syn, CgA, CD3, CD8, CD20, CD68, and CD163 were also stained on tissue samples. Then prognostic factors of lung LCNEC were explored.

Results

One hundred and fifty-one lung LCNEC patients were identified, 103 of whom had complete clinical information, available routine blood and biochemical indexes were eventually included in the present study. Tumor tissue specimens were available from 64 patients. Positive expression rates of ASCL1, NEUROD1, and YAP1 were 82.8%, 50.0%, and 28.1%, respectively. No POU2F3+ cases were detected. Forty (62.5%) patients co-expressed with two or three markers. High LMR (>3.3) was an independent predictor of favorable prognosis of disease-free survival (DFS) [hazard ratio (HR), 0.391; 95% confidence interval (CI): 0.161-0.948; P=0.04] and overall survival (OS) (HR, 0.201; 95% CI: 0.071-0.574; P=0.003). Notably, high LMR was correlated with higher intra-tumoral CD3+ (P=0.004), CD8+ (P=0.01), and CD68+ (P<0.001) immune cell infiltration compared to low LMR in lung LCNEC.

Conclusions

Our study validated molecular subtypes by IHC in lung LCNEC, and co-expression was found among different subtypes, with no prognostic effect. High blood LMR level was associated with a favorable prognosis in lung LCNEC, which might partly reflect a hot tumor tissue immune microenvironment. Our findings may benefit clinical practice, and further studies are warranted.

Insights into the Two Most Common Cancers of Primitive Gut-Derived Structures and Their Microbial Connections

The gastrointestinal and respiratory systems are closely linked in different ways, including from the embryological, anatomical, cellular, and physiological angles. The highest number (and various types) of microorganisms live in the large intestine/colon, and constitute the normal microbiota in healthy people. Adverse alterations of the microbiota or dysbiosis can lead to chronic inflammation. If this detrimental condition persists, a sequence of pathological events can occur, such as inflammatory bowel disease, dysplasia or premalignant changes, and finally, cancer. One of the most commonly identified bacteria in both inflammatory bowel disease and colon cancer is Escherichia coli. On the other hand, patients with inflammatory bowel disease are at risk of several other diseases-both intestinal (such as malnutrition and intestinal obstruction, besides cancer) and extraintestinal (such as arthritis, bronchiectasis, and cancer risk). Cancers of the lung and colon are the two most common malignancies occurring worldwide (except for female breast cancer). Like the bacterial role in colon cancer, many studies have shown a link between chronic Chlamydia pneumoniae infection and lung cancer. However, in colon cancer, genotoxic colibactin-producing E. coli belonging to the B2 phylogroup may promote tumorigenesis. Furthermore, E. coli is believed to play an important role in the dissemination of cancer cells from the primary colonic site. Currently, seven enteric pathogenic E. coli subtypes have been described. Conversely, three Chlamydiae can cause infections in humans (C. trachomatis may increase the risk of cervical and ovarian cancers). Nonetheless, striking genomic plasticity and genetic modifications allow E. coli to constantly adjust to the surrounding environment. Consequently, E. coli becomes resistant to antibiotics and difficult to manage. To solve this problem, scientists are thinking of utilizing suitable lytic bacteriophages (viruses that infect and kill bacteria). Several bacteriophages of E. coli and Chlamydia species are being evaluated for this purpose.

Metabolomic Profiling of Pulmonary Neuroendocrine Neoplasms

BACKGROUND/OBJECTIVES

Pulmonary neuroendocrine neoplasms (NENs) account for 20% of malignant lung tumors. Their management is challenging due to their diverse clinical features and aggressive nature. Currently, metabolomics offers a range of potential cancer biomarkers for diagnosis, monitoring tumor progression, and assessing therapeutic response. However, a specific metabolomic profile for early diagnosis of lung NENs has yet to be identified. This study aims to identify specific metabolomic profiles that can serve as biomarkers for early diagnosis of lung NENs.

METHODS

We measured 153 metabolites using liquid chromatography combined with mass spectrometry (LC-MS) in the plasma of 120 NEN patients and compared them with those of 71 healthy individuals. Additionally, we compared these profiles with those of 466 patients with non-small-cell lung cancers (NSCLCs) to ensure clinical relevance.

RESULTS

We identified 21 metabolites with consistently altered plasma concentrations in NENs. Compared to healthy controls, 18 metabolites were specific to carcinoid tumors, 5 to small-cell lung carcinomas (SCLCs), and 10 to large-cell neuroendocrine carcinomas (LCNECs). These findings revealed alterations in various metabolic pathways, such as fatty acid biosynthesis and beta-oxidation, the Warburg effect, and the citric acid cycle.

CONCLUSIONS

Our study identified biomarker metabolites in the plasma of patients with each subtype of lung NENs and demonstrated significant alterations in several metabolic pathways. These metabolomic profiles could potentially serve as biomarkers for early diagnosis and better management of lung NENs.

Effect of Ki-67 proliferation index on survival in large cell neuroendocrine carcinoma of the lung

OBJECTIVE

Large cell neuroendocrine carcinoma of the lung is a rare type of lung cancer. There is a limited number of studies on clinical and histopathological characteristics that are effective in survival. The aim of this study was to investigate the relationship between histopathological and clinical characteristics, mainly Ki-67 proliferation index, and survival in patients diagnosed with large cell neuroendocrine carcinoma of the lung.

METHODS

The data of 38 patients followed up with the diagnosis of large cell neuroendocrine carcinoma of the lung were evaluated. The mean Ki-67 value was determined to be 65.8% (±20.8). The patients' clinical characteristics and survival times were compared according to the cut-off value determined for Ki-67 index.

RESULTS

When median overall survival times were compared, it was seen that overall survival was numerically lower in patients aged 65 years and over, in tumors located on the right side, in cases who were in the metastatic stage at diagnosis, whose Ki-67 index was 65% and above, who did not receive chemotherapy, who did not undergo curative surgery, and in patients with chronic diseases (p>0.05). In the Kaplan-Meier analysis, the median overall survival was determined to be 22.2 months (95%CI 21.7-22.7) in the patients with Ki-67<65%, while it was found to be 20.3 months (95%CI 4.5-36.2) in the patients with Ki-67≥65% (p=0.351).

CONCLUSION

Our study identified subgroups with decreased survival in large cell neuroendocrine carcinoma of lung patients. Studies including a larger number of patients are needed to identify the prognostic importance of these clinical and histopathological characteristics.

PROX1 is a regulator of neuroendocrine-related gene expression in lung carcinoid

Lung neuroendocrine neoplasms (NENs) are a diverse group of tumors characterized by neuroendocrine (NE) differentiation. Among lung NENs, lung carcinoid (LC) is a rare tumor with unique characteristics. Recent research has highlighted the importance of transcription factors (TFs) in establishing gene expression programs in lung NENs such as small cell lung carcinoma. However, the TFs that control the gene expression of LC are largely unknown. In this study, we report the expression and potential function of a TF called Prospero homeobox protein1 (PROX1) in LC. Publicly available transcriptome data suggested that PROX1 was highly expressed in LC tissues, which was confirmed by immunohistochemical analysis on a tissue microarray. Knockdown of PROX1 did not impact the cellular viability of an LC-derived cell line, NCI-H727. Meanwhile, transcriptome analysis revealed that PROX1 knockdown altered the expression of genes involved in NE differentiation. ASCL1, CHGA, CALCA, and LINC00261 were suggested as downstream genes of PROX1. These findings indicate that PROX1 may play an important role in the NE identity of LC by regulating the expression of key target genes.

CT Texture Analysis of Perihilar Cholangiocarcinoma-Associations With Tumor Grading, Tumor Markers and Clinical Outcome

BACKGROUND

Texture analysis derived from computed tomography (CT) may provide clinically relevant imaging biomarkers associated with tumor histopathology. Perihilar cholangiocarcinoma is a malignant disease with an overall poor prognosis.

AIMS

The present study sought to elucidate possible associations between texture features derived from CT images with grading, tumor markers, and survival in extrahepatic, perihilar cholangiocarcinomas tumors.

METHODS

This retrospective study included 22 patients (10 females, 45%) with a mean age of 71.8 ± 8.7 years. Texture analysis was performed using the free available Mazda software. All tumors were histopathologically confirmed. Survival and clinical parameters were used as primary study outcomes.

RESULTS

In discrimination analysis, "S(1,1)SumVarnc" was statistically significantly different between patients with long-term survival and nonlong-term survival (mean 275.8 ± 32.6 vs. 239.7 ± 26.0, p = 0.01). The first-order parameter "skewness" was associated with the tumor marker "carcinoembryonic antigen" (CEA) (r = -0.7, p = 0.01). A statistically significant correlation of the texture parameter "S(5,0)SumVarnc" with tumor grading was identified (r = -0.6, p < 0.01). Several other texture features correlated with tumor markers CA-19-9 and AFP, as well as with T and N stage of tumors.

CONCLUSION

Several texture features derived from CT images were associated with tumor characteristics and survival in patients with perihilar cholangiocarcinomas. CT texture features could be used as valuable novel imaging markers in clinical routine.

The prognostic analysis and a machine-learning based disease-specific survival state model in pulmonary large-cell neuroendocrine carcinomas

Background

Pulmonary large-cell neuroendocrine carcinoma (PLCNEC) is a rare and highly malignant lung cancer. Due to the paucity of data from clinical studies, its clinical characteristics and treatment remain controversial. The present study explored factors influencing the prognosis and survival outcomes of patients with PLCNEC and developed a dependable prognostic model using machine learning.

Methods

The clinical data of PLCNEC patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2020. A total of 2,897 PLCNEC patients were enrolled and univariate and multivariate Cox regression analyses were performed to explore independent prognostic factors for disease-specific survival (DSS). Ten machine learning algorithms were utilized to predict the 2-year survival. The clinicopathological data collected from The First Affiliated Hospital of Sun Yat-sen University between 2010 and 2022 were used to test the trained machine.

Results

Sex [hazard ratio (HR) 1.168, 95% confidence interval (CI): 1.063-1.284], age (HR 1.262, 95% CI: 1.144-1.391), surgery (HR 0.481, 95% CI: 0.413-0.559), chemotherapy (HR 0.450, 95% CI: 0.404-0.501), bone metastasis (HR 1.284, 95% CI: 1.124-1.466), brain metastasis (HR 1.167, 95% CI: 1.023-1.331), liver metastasis (HR 1.223, 95% CI: 1.069-1.399), American Joint Committee on Cancer-Node (AJCC-N), and tumor stage were independent prognostic factors. The gradient boosting decision tree (GBDT) performed better than other models, with an F1-score of 0.791 and an area under the curve of 0.831.

Conclusions

Male, age ≥65 years, distant metastasis to the bone, liver, and brain are associated with a worse prognosis in PLCNEC patients, while surgery and chemotherapy are associated with improved prognosis. GBDT showed promising performance in predicting 2-year survival, which can serve as a valuable reference for clinical diagnosis and treatment of PLCNEC.

[Advances of Treatment of Pulmonary Large Cell Neuroendocrine Carcinoma]

Large cell neuroendocrine carcinoma (LCNEC) of lung is a rare neuroendocrine carcinoma subtype with difficulty in early diagnosis and poor prognosis which is treated with standard strategies of small cell lung cancer and non-small cell lung cancer. In recent years, the precise types of LCNEC and its response to therapy have been identified by next-generation sequencing. Some researches have also found the correlation between different subtypes of LCNEC and the efficacy of chemotherapy regimens. However, there is no consensual agreement of its therapy. Recently, immune checkpoint inhibitors (ICIs) has provided a new option for LCNEC patients based on some retrospective research data and case reports. In this review, we aimed to summarize the epidemiological characteristics, standard therapy, the advances of molecular subtypes and clinical applications of ICIs of LCNEC, so as to provide optimal systemic clinical decision-making for LCNEC patients.
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Role of Bone Metastases in Lung Neuroendocrine Neoplasms: Clinical Presentation, Treatment and Impact on Prognosis

Lung neuroendocrine neoplasms (L-NEN) are heterogeneous tumors. While bone metastases (BM) have been associated with worse prognosis in other NEN, their role in L-NEN deserves in-depth analysis. This study analyzes the clinical presentation, treatment and survival outcomes of L-NEN, focusing on patients with BM compared with patients without metastases or with metastases in other sites (OtherMtx). The clinicopathological and survival data of L-NEN admitted to the Federico II University were retrospectively evaluated. Fifty L-NEN were included. Among 27 metastatic patients (54%), 13 (26%) had BM, more commonly occurring in males than females and in primary bilateral L-NEN or L-NEN > 26 mm, with higher Ki67. Atypical carcinoid and hypovitaminosis D were associated with BM. The number of metastatic sites was higher in patients with BM than OtherMtx. Synchronous metastases were associated with shorter overall survival (OS). The median progression-free survival (PFS) and OS in patients with BM were similar to OtherMtx, but a two-times increased risk of shorter OS was detected. BM do not impact PFS or OS more than OtherMtx, but the increased risk of shorter OS in patients with BM should be considered. Periodic bone evaluation in L-NEN should be recommended.

An Overview of Altered Pathways Associated with Sensitivity to Platinum-Based Chemotherapy in Neuroendocrine Tumors: Strengths and Prospects

Neuroendocrine neoplasms (NENs) are a diverse group of malignancies with a shared phenotype but varying prognosis and response to current treatments. Based on their morphological features and rate of proliferation, NENs can be classified into two main groups with a distinct clinical behavior and response to treatment: (i) well-differentiated neuroendocrine tumors (NETs) or carcinoids (with a low proliferation rate), and (ii) poorly differentiated small- or large-cell neuroendocrine carcinomas (NECs) (with a high proliferation rate). For certain NENs (such as pancreatic tumors, higher-grade tumors, and those with DNA damage repair defects), chemotherapy is the main therapeutic approach. Among the different chemotherapic agents, cisplatin and carboplatin, in combination with etoposide, have shown the greatest efficacy in treating NECs compared to NETs. The cytotoxic effects of cisplatin and carboplatin are primarily due to their binding to DNA, which interferes with normal DNA transcription and/or replication. Consistent with this, NECs, which often have mutations in pathways involved in DNA repair (such as Rb, MDM2, BRCA, and PTEN), have a high response to platinum-based chemotherapy. Identifying mutations that affect molecular pathways involved in the initiation and progression of NENs can be crucial in predicting the response to platinum chemotherapy. This review aims to highlight targetable mutations that could serve as predictors of therapeutic response to platinum-based chemotherapy in NENs.

Clinical management of typical and atypical carcinoids/neuroendocrine tumors in ENETS centres of excellence (CoE): Survey from the ENETS lung NET task force

Lung carcinoid tumours are neuroendocrine neoplasms originating from the bronchopulmonary tract's neuroendocrine cells, accounting for only 1%-3% of all lung cancers but 30% of all neuroendocrine tumours. The incidence of lung carcinoids, both typical and atypical, has been increasing over the years due to improved diagnostic methods and increased awareness among clinicians and pathologists. The most recent WHO classification includes a subgroup of lung carcinoids with atypical morphology and higher mitotic count and/or Ki67 labelling index. Despite appropriate surgery, the 5-year survival rate for atypical carcinoids barely exceeds 50%-70%. The role of adjuvant therapy in lung carcinoids is not well-defined, and clinical decisions are generally based on the presence of high-risk features. Long-term follow-up is essential to monitor for recurrence, although the optimal follow-up protocol remains unclear. To address the lack of consensus in clinical management decisions, the European Neuroendocrine Tumor Society (ENETS) initiated a survey among 20 expert centres. The survey identified varied opinions on approaches to imaging, surgery, use of adjuvant therapy, and follow-up protocols. Notably, the absence of dedicated multidisciplinary lung neuroendocrine tumour boards in some centres was evident. Experts agreed on the need for a prospective adjuvant trial in high-risk patients, emphasizing the feasibility of such a study. In conclusion, the study highlights the need for a more uniform adoption of existing guidelines in the management of lung carcinoid tumours and emphasizes the importance of international collaboration to advance research and patient care. Close collaboration between healthcare providers and patients is vital for effective long-term surveillance and management of these rare tumours.

Transcription Factor yin-Yang 1 augments nucleoporin 93 oncogene activity and modulates bladder Cancer malignancy

OBJECTIVE

This study aims to investigate the functional interplay between transcription factor YY1 and nucleoporin 93 (NUP93) in regulating the malignancy of bladder cancer cells.

METHODS

NUP93 expressions in bladder cancer tissues and normal counterparts were analyzed using a public dataset and clinical samples. NUP93 and Yin Yang 1 (YY1) mRNA expression and protein levels in T24 and RT4 cells were determined by Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. The effect of NUP93 knockdown on the proliferation, migration, and invasion capabilities of cells was evaluated. Concurrently, transcriptional regulation of NUP93 by YY1 was confirmed using a dual luciferase assay. The effect of NUP93 knockdown on tumorigenesis was evaluate in a subcutaneous xenograft mouse model.

RESULTS

Elevated levels of NUP93 in bladder cancer tissues and cell lines were observed. Silencing NUP93 significantly suppressed glycolysis, impeded the growth, migration, invasion and tumor formation of bladder cancer cells. The transcription factor YY1 acted as a positive regulator to upregulate NUP93 expression. YY1 overexpression partially rescued the effects of NUP93 silencing on bladder cancer cells.

CONCLUSION

Our results uncovered transcription factor YY1 as a positive regulator of NUP93 expression, and NUP93 serves as an oncogenic factor to sustain the malignancy of bladder cancer cells. These findings suggest that targeting the YY1-NUP93 axis could offer novel therapeutic strategies for bladder cancer treatment.

Targeting SOX4/PCK2 signaling suppresses neuroendocrine trans-differentiation of castration-resistant prostate cancer

BACKGROUND

Neuroendocrine prostate cancer (NEPC), a lethal subset of prostate cancer (PCa), is characterized by loss of AR signaling and resistance to AR-targeted therapy. While it is well reported that second-generation AR blockers induce neuroendocrine (NE) trans-differentiation of castration-resistant prostate cancer (CRPC) to promote the occurrence of NEPC, and pluripotent transcription factors might be potential regulators, the underlying molecular mechanisms remain unclear.

METHODS

We analyzed the data from public databsets to screen candidate genes and then focused on SOX4, a regulator of NE trans-differentiation. The expression changes of SOX4 and its relationship with tumor progression were validated in clinical tumor tissues. We evaluated malignant characteristics related to NEPC in prostate cancer cell lines with stable overexpression or knockdown of SOX4 in vitro. Tumor xenografts were analyzed after inoculating the relevant cell lines into nude mice. RNA-seq, ATAC-seq, non-targeted metabolomics analysis, as well as molecular and biochemical assays were carried out to determine the mechanism.

RESULTS

We screened public datasets and identified that expression of SOX4 was significantly elevated in NEPC. Overexpressing SOX4 in C4-2B cells increased cell proliferation and migration, upregulated the expression of NE marker genes, and inhibited AR expression. Consistently, inhibition of SOX4 expression in DU-145 and PC-3 cells reduced the above malignant phenotypes and repressed the expression of NE marker genes. For the in vivo assay, we found that knockdown of SOX4 inhibited tumor growth of subcutaneous xenografts in castrated nude mice which were concomitantly treated with enzalutamide (ENZ). Mechanically, we identified that one of the key enzymes in gluconeogenesis, PCK2, was a novel target of SOX4. The activation of carbohydrate metabolism reprogramming by SOX4 could promote NE trans-differentiation via the SOX4/PCK2 pathway.

CONCLUSIONS

Our findings reveal that SOX4 promotes NE trans-differentiation both in vitro and in vivo via directly enhancing PCK2 activity to activate carbohydrate metabolism reprogramming. The SOX4/PCK2 pathway and its downstream changes might be novel targets for blocking NE trans-differentiation.

An Illustrated Review of the Recent 2019 World Health Organization Classification of Neuroendocrine Neoplasms: A Radiologic and Pathologic Correlation

ABSTRACT

Recent advances in molecular pathology and an improved understanding of the etiology of neuroendocrine neoplasms (NENs) have given rise to an updated World Health Organization classification. Since gastroenteropancreatic NENs (GEP-NENs) are the most common forms of NENs and their incidence has been increasing constantly, they will be the focus of our attention. Here, we review the findings at the foundation of the new classification system, discuss how it impacts imaging research and radiological practice, and illustrate typical and atypical imaging and pathological findings. Gastroenteropancreatic NENs have a highly variable clinical course, which existing classification schemes based on proliferation rate were unable to fully capture. While well- and poorly differentiated NENs both express neuroendocrine markers, they are fundamentally different diseases, which may show similar proliferation rates. Genetic alterations specific to well-differentiated neuroendocrine tumors graded 1 to 3 and poorly differentiated neuroendocrine cancers of small cell and large-cell subtype have been identified. The new tumor classification places new demands and creates opportunities for radiologists to continue providing the clinically most relevant report and on researchers to design projects, which continue to be clinically applicable.

Clinical Evaluation of Response to Octreotide and Chemotherapy in High-Grade Malignant Neuroendocrine Tumors and Promising In Vitro Preclinical Results with Pasireotide

Background and Objectives: High-grade malignant neuroendocrine tumors (G3 NETs) and neuroendocrine carcinomas (NECs) are characterized by rapid proliferation, high metastatic capacity, and strong expression of somatostatin receptors (SSTRs). We aimed to analyze the presence of SSTRs in NET G3 and NEC, and to correlate their expression with the use of octreotide and pasireotide. Materials and Methods: For this purpose, we first performed a retrospective study of G3 NET and NEC patients, which included the determination of SSTR expression and response to octreotide treatment. Second, we selected the H69 small cell lung cancer cell line to determine the effect of octreotide and pasireotide. Results: Our results showed the traditional somatostatin analog (SSA) octreotide was ineffective in patients with NET G3 and NEC. On the other hand, RT-qPCR showed a high expression of SSTR2 and SSTR5 in H69 cells. Interestingly, while octreotide did not modify H69 cell proliferation, a strong inhibition of proliferation was detected with the use of pasireotide. Conclusions: In view of these results, a clinical trial in NET G3 and NEC patients using pasireotide is necessary to determine the usefulness of this drug in improving patient treatment.

Long-term outcomes and prognosis of neuroendocrine neoplasms of the head and neck: a cohort from a single institution

BACKGROUND

Neuroendocrine neoplasm is a rare cancer of head and neck. This study aimed to evaluate clinical features, treatment outcomes, and prognostic factors of neuroendocrine neoplasm of head and neck treated at a single institution.

METHODS

Between Nov 2000 and Nov 2021, ninety-three patients diagnosed with neuroendocrine neoplasms of head and neck treated at our institution were reviewed retrospectively. The initial treatments included chemotherapy (induction, adjuvant, or concurrent) combined with radiotherapy in 40 patients (C + RT group), surgery followed by post-operative RT in 34 (S + RT group), and surgery plus salvage therapy in 19 patients (S + Sa group).

RESULTS

The median follow-up time was 64.5 months. 5-year overall survival rate (OS), progression-free survival rate (PFS), loco-regional relapse-free survival free rate (LRRFS) and distant metastasis-free survival rate (DMFS) were 64.5%, 51.6%, 66.6%, and 62.1%, respectively. For stage I-II, the 5-year LRRFS for patients' treatment regimen with or without radiotherapy (C + RT and S + RT groups versus S + Sa group) was 75.0% versus 12.7% (p = 0.015) while for stage III-IV, the 5-year LRRFS was 77.8% versus 50.0% (p = 0.006). The 5-year DMFS values for patients with or without systemic therapy (C + RT group versus S + RT or S + Sa) were 71.2% and 51.5% (p = 0.075). 44 patients (47.3%) experienced treatment failure and distant metastasis was the main failure pattern.

CONCLUSIONS

Radiotherapy improved local-regional control and played an important role in the management of HNNENs. The optimal treatment regimen for HNNENs remains the combination of local and systemic treatments.

Molecular Classification of Gastrointestinal and Pancreatic Neuroendocrine Neoplasms: Are We Ready for That?

In the last two decades, the increasing availability of technologies for molecular analyses has allowed an insight in the genomic alterations of neuroendocrine neoplasms (NEN) of the gastrointestinal tract and pancreas. This knowledge has confirmed, supported, and informed the pathological classification of NEN, clarifying the differences between neuroendocrine carcinomas (NEC) and neuroendocrine tumors (NET) and helping to define the G3 NET category. At the same time, the identification genomic alterations, in terms of gene mutation, structural abnormalities, and epigenetic changes differentially involved in the pathogenesis of NEC and NET has identified potential molecular targets for precision therapy. This review critically recapitulates the available molecular features of digestive NEC and NET, highlighting their correlates with pathological aspects and clinical characteristics of these neoplasms and revising their role as predictive biomarkers for targeted therapy. In this context, the feasibility and applicability of a molecular classification of gastrointestinal and pancreatic NEN will be explored.

Assessment of the current and emerging criteria for the histopathological classification of lung neuroendocrine tumours in the lungNENomics project

BACKGROUND

Six thoracic pathologists reviewed 259 lung neuroendocrine tumours (LNETs) from the lungNENomics project, with 171 of them having associated survival data. This cohort presents a unique opportunity to assess the strengths and limitations of current World Health Organization (WHO) classification criteria and to evaluate the utility of emerging markers.

PATIENTS AND METHODS

Patients were diagnosed based on the 2021 WHO criteria, with atypical carcinoids (ACs) defined by the presence of focal necrosis and/or 2-10 mitoses per 2 mm2. We investigated two markers of tumour proliferation: the Ki-67 index and phospho-histone H3 (PHH3) protein expression, quantified by pathologists and automatically via deep learning. Additionally, an unsupervised deep learning algorithm was trained to uncover previously unnoticed morphological features with diagnostic value.

RESULTS

The accuracy in distinguishing typical from ACs is hampered by interobserver variability in mitotic counting and the limitations of morphological criteria in identifying aggressive cases. Our study reveals that different Ki-67 cut-offs can categorise LNETs similarly to current WHO criteria. Counting mitoses in PHH3+ areas does not improve diagnosis, while providing a similar prognostic value to the current criteria. With the advantage of being time efficient, automated assessment of these markers leads to similar conclusions. Lastly, state-of-the-art deep learning modelling does not uncover undisclosed morphological features with diagnostic value.

CONCLUSIONS

This study suggests that the mitotic criteria can be complemented by manual or automated assessment of Ki-67 or PHH3 protein expression, but these markers do not significantly improve the prognostic value of the current classification, as the AC group remains highly unspecific for aggressive cases. Therefore, we may have exhausted the potential of morphological features in classifying and prognosticating LNETs. Our study suggests that it might be time to shift the research focus towards investigating molecular markers that could contribute to a more clinically relevant morpho-molecular classification.

Multiple bronchial carcinoids associated with Cowden syndrome

Cowden syndrome (CS) is a rare genetic condition due to the various germline mutations in the phosphatase and tensin homologue on chromosome ten (PTEN) tumour suppressor gene. As a result, CS is characterised by an increased risk of developing various benign and malignant tumours, such as thyroid, breast, endometrial and urogenital neoplasms, as well as gastrointestinal tract tumours. However, the neuroendocrine tumour association with CS is not elucidated yet. We present a case of a 46-year-old male patient diagnosed with testicular seminoma and follicular thyroid cancer in his medical history. Our patient met the clinical diagnostic criteria of Cowden syndrome. Genetic analysis established the clinical diagnosis; a known heterozygous PTEN mutation was detected [PTEN (LRG_311t1)c.388 C > T (p.Arg130Ter)]. Incidentally, he was also seen with multiple pulmonary lesions during his oncological follow-up. A video-assisted thoracoscopic left lingula wedge resection and later resections from the right lung were performed. Histological findings revealed typical pulmonary carcinoid tumours and smaller tumorlets. Somatostatin receptor SPECT-CT, 18F-FDG-PET-CT and 18F-FDOPA-PET-CT scans and endoscopy procedures could not identify any primary tumours in other locations. Our patient is the first published case of Cowden syndrome, associated with multifocal pulmonary carcinoids. Besides multiple endocrine neoplasia type 1, we propose Cowden syndrome as another hereditary condition predisposing to multiple pulmonary tumorlets and carcinoid tumours.

Expression patterns of novel immunotherapy targets in intermediate- and high-grade lung neuroendocrine neoplasms

BACKGROUND

Advancements in immunotherapeutic approaches only had a modest impact on the therapy of lung neuroendocrine neoplasms (LNENs). Our multicenter study aimed to investigate the expression patterns of novel immunotherapy targets in intermediate- and high-grade LNENs.

METHODS

The expressions of V-domain Ig suppressor of T cell activation (VISTA), OX40L, Glucocorticoid-induced TNF receptor (GITR), and T cell immunoglobulin and mucin domain 3 (TIM3) proteins were measured by immunohistochemistry in surgically resected tumor samples of 26 atypical carcinoid (AC), 49 large cell neuroendocrine lung cancer (LCNEC), and 66 small cell lung cancer (SCLC) patients. Tumor and immune cells were separately scored.

RESULTS

Tumor cell TIM3 expression was the highest in ACs (p < 0.001), whereas elevated tumor cell GITR levels were characteristic for both ACs and SCLCs (p < 0.001 and p = 0.011, respectively). OX40L expression of tumor cells was considerably lower in ACs (vs. SCLCs; p < 0.001). Tumor cell VISTA expression was consistently low in LNENs, with no significant differences across histological subtypes. ACs were the least immunogenic tumors concerning immune cell abundance (p < 0.001). Immune cell VISTA and GITR expressions were also significantly lower in these intermediate-grade malignancies than in SCLCs or in LCNECs. Immune cell TIM3 and GITR expressions were associated with borderline prognostic significance in our multivariate model (p = 0.057 and p = 0.071, respectively).

CONCLUSIONS

LNEN subtypes have characteristic and widely divergent VISTA, OX40L, GITR, and TIM3 protein expressions. By shedding light on the different expression patterns of these immunotherapy targets, the current multicenter study provides support for the future implementation of novel immunotherapeutic approaches.

All That Is Small Is Not a Small-Cell Carcinoma: Thoracic SMARCA4-Deficient Undifferentiated Tumors Masquerading as SCLC

Small-cell lung carcinoma (SCLC) cell lines have been widely utilized as a preclinical model of this highly aggressive disease. However, since their creation decades ago, novel tumor entities have been defined that might clinicopathologically mimic SCLC, which notably includes thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT). Multiomic reassessment of the presumed SCLC cell lines with high YAP1 expression reveals that nearly all of these tumors represent unsuspected SMARCA4-UT. See related article by Ng et al., p. 1846.

POU2F3-positive small cell carcinoma of the bladder: A clinicopathologic analysis of 4 cases and literature review

POU class 2 homeobox 3 (POU2F3)-positive small cell bladder carcinoma (SCBC) is an extremely rare entity, and its clinicopathologic features have not been fully described. Here, we investigated the clinicopathologic features of 4 cases of POU2F3-positive small cell bladder carcinoma (SCBC) and reviewed the literature. We collected 12 cases of SCBC from our departmental archives and detected the expression of POU2F3 by immunohistochemical (IHC) staining. Selected cases with or without POU2F3 expression were subjected to gene expression analysis between two different groups using DESeq2 software. We identified 4 POU2F3-positive SCBC patients, 2 males and 2 females, with a mean age of 77 years. Three patients had hematuria, and 1 patient had dysuria. Radiologic findings showed a bladder mass. Pathologic diagnosis showed that 3 cases were pure SCBC and 1 was mixed urothelial cancer (UC). Histopathologically, four POU2F3-positive SCBC tumors were composed of small round cells with sparse cytoplasm, the nuclei were salt-and-pepper-like or finely granular. Tumor cells showed characteristic cytoplasmic staining with punctate positive signals for cytokeratin. Syn and CD56 were diffusely positive in all the 4 patients. CgA was positive in only one patient. POU2F3-positive SCBC showed higher expression levels of POU2F3, HMGA2 and PLCG2 genes by RNA-Seq. Our data showed the specific clinicopathologic features of 4 rare POU2F3-positive SCBC cases, and the distinct molecular feature was observed between POU2F3-positive and negative SCBC in the limited number of cases.

Molecular and Pathologic Characterization of YAP1-Expressing Small Cell Lung Cancer Cell Lines Leads to Reclassification as SMARCA4-Deficient Malignancies

PURPOSE

The classification of small cell lung cancer (SCLC) into distinct molecular subtypes defined by ASCL1, NEUROD1, POU2F3, or YAP1 (SCLC-A, -N, -P, or -Y) expression, paves the way for a personalized treatment approach. However, the existence of a distinct YAP1-expressing SCLC subtype remains controversial.

EXPERIMENTAL DESIGN

To better understand YAP1-expressing SCLC, the mutational landscape of human SCLC cell lines was interrogated to identify pathogenic alterations unique to SCLC-Y. Xenograft tumors, generated from cell lines representing the four SCLC molecular subtypes, were evaluated by a panel of pathologists who routinely diagnose thoracic malignancies. Diagnoses were complemented by transcriptomic analysis of primary tumors and human cell line datasets. Protein expression profiles were validated in patient tumor tissue.

RESULTS

Unexpectedly, pathogenic mutations in SMARCA4 were identified in six of eight SCLC-Y cell lines and correlated with reduced SMARCA4 mRNA and protein expression. Pathologist evaluations revealed that SMARCA4-deficient SCLC-Y tumors exhibited features consistent with thoracic SMARCA4-deficient undifferentiated tumors (SMARCA4-UT). Similarly, the transcriptional profile SMARCA4-mutant SCLC-Y lines more closely resembled primary SMARCA4-UT, or SMARCA4-deficient non-small cell carcinoma, than SCLC. Furthermore, SMARCA4-UT patient samples were associated with a YAP1 transcriptional signature and exhibited strong YAP1 protein expression. Together, we found little evidence to support a diagnosis of SCLC for any of the YAP1-expressing cell lines originally used to define the SCLC-Y subtype.

CONCLUSIONS

SMARCA4-mutant SCLC-Y cell lines exhibit characteristics consistent with SMARCA4-deficient malignancies rather than SCLC. Our findings suggest that, unlike ASCL1, NEUROD1, and POU2F3, YAP1 is not a subtype defining transcription factor in SCLC. See related commentary by Rekhtman, p. 1708.

ETV6-NTRK2 Fusion in a Patient With Metastatic Pulmonary Atypical Carcinoid Successfully Treated With Entrectinib: A Case Report and Review of the Literature

Pulmonary atypical carcinoid (AC) is an extremely rare neuroendocrine tumor. The neurotrophic tropomyosin receptor kinase (NTRK) fusions are reported in only 0.5% of nonsmall cell lung cancer, and are more rare in AC with only one previously reported case. Currently, there is little established evidence on the optimal therapeutic strategies and prognosis for advanced cases. We present a female patient with metastatic AC after complete resection. Due to low expression of somatostatin receptor in this case, somatostatin analogs and peptide receptor radionuclide therapy were not available. After pursuing other alternative treatments, including chemotherapy (ie, carboplatin, etoposide, capecitabine, temozolomide, and paclitaxel), everolimus, and atezolizumab, she returned with significant progression, including innumerable subcutaneous nodules, left pleura metastasis, multiple bone metastases, and brain metastases. New biopsy analysis revealed an ETV6-NTRK2 fusion. She was immediately administered the first-generation tropomyosin receptor kinase inhibitor entrectinib at a dose of 600 mg q.d. A subsequent month of treatment resulted in a complete response in all of the metastatic lung lesions. To date, she has maintained sustained benefit for at least 1 year from initiation of entrectinib. Here, we present the first case of a female patient with metastatic AC harboring the ETV6-NTRK2 fusion, and successfully treated with entrectinib, providing evidence for the application of entrectinib in patients with NTRK-positive AC, and underscoring the critical role of molecular profiling for such cases.

Investigating pulmonary neuroendocrine cells in human respiratory diseases with airway models

Despite accounting for only ∼0.5% of the lung epithelium, pulmonary neuroendocrine cells (PNECs) appear to play an outsized role in respiratory health and disease. Increased PNEC numbers have been reported in a variety of respiratory diseases, including chronic obstructive pulmonary disease and asthma. Moreover, PNECs are the primary cell of origin for lung neuroendocrine cancers, which account for 25% of aggressive lung cancers. Recent research has highlighted the crucial roles of PNECs in lung physiology, including in chemosensing, regeneration and immune regulation. Yet, little is known about the direct impact of PNECs on respiratory diseases. In this Review, we summarise the current associations of PNECs with lung pathologies, focusing on how new experimental disease models, such as organoids derived from human pluripotent stem cells or tissue stem cells, can help us to better understand the contribution of PNECs to respiratory diseases.