Pulmonary Neuroendocrine Cells Research Articles

Molecular pathology of small cell lung cancer: Overview from studies on neuroendocrine differentiation regulated by ASCL1 and Notch signaling.

Pulmonary neuroendocrine (NE) cells are rare airway epithelial cells. The balance between Achaete-scute complex homolog 1 (ASCL1) and hairy and enhancer of split 1, one of the target molecules of the Notch signaling pathway, is crucial for NE differentiation. Small cell lung cancer (SCLC) is a highly aggressive lung tumor, characterized by rapid cell proliferation, a high metastatic potential, and the acquisition of resistance to treatment. The subtypes of SCLC are defined by the expression status of NE cell-lineage transcription factors, such as ASCL1, which roles are supported by SRY-box 2, insulinoma-associated protein 1, NK2 homeobox 1, and wingless-related integration site signaling. This network reinforces NE differentiation and may induce the characteristic morphology and chemosensitivity of SCLC. Notch signaling mediates cell-fate decisions, resulting in an NE to non-NE fate switch. The suppression of NE differentiation may change the histological type of SCLC to a non-SCLC morphology. In SCLC with NE differentiation, Notch signaling is typically inactive and genetically or epigenetically regulated. However, Notch signaling may be activated after chemotherapy, and, in concert with Yes-associated protein signaling and RE1-silencing transcription factor, suppresses NE differentiation, producing intratumor heterogeneity and chemoresistance. Accumulated information on the molecular mechanisms of SCLC will contribute to further advances in the control of this recalcitrant cancer.

Distinct regulation of ASCL1 by the cell cycle and chemotherapy in small cell lung cancer.

Small cell lung cancer (SCLC) is an aggressive and lethal malignancy. Achaete-scute homolog 1 (ASCL1) is essential for the initiation of SCLC in mice and the development of pulmonary neuroendocrine cells (PNECs) which are the major cells of origin for SCLC. However, the regulatory mechanism of ASCL1 in SCLC remains elusive. Here, we found that ASCL1 expression gradually increases as the tumors grow in a mouse SCLC model and is regulated by the cell cycle. Mechanistically CDK2-CyclinA2 complex phosphorylates ASCL1, which results in increased proteasome-mediated ASCL1 protein degradation by E3 ubiquitin ligase HUWE1 during mitosis. TCF3 promotes the multi-site phosphorylation of ASCL1 through the CDK2-CyclinA2 complex and the interaction between ASCL1 and TCF3 protects ASCL1 from degradation. The dissociation of TCF3 from ASCL1 during mitosis accelerates the degradation of ASCL1. In addition, chemotherapy drugs greatly reduce the transcription of ASCL1 in SCLC cells. Depletion of ASCL1 sensitizes SCLC cells to chemotherapy drugs. Together, our study demonstrates that ASCL1 is a cell-cycle regulated protein and provides a theoretical basis for applying cell-cycle related antitumor drugs in SCLC treatment. Implications: Our study revealed a novel regulatory mechanism of ASCL1 by cell cycle and chemotherapy drugs in SCLC. Treating SCLC patients with a combination of ASCL1-targeting therapy and chemotherapy drugs could potentially be beneficial.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia in adults

Diffuse Idiopathic Pulmonary NeuroEndocrine Cell Hyperplasia (DIPNECH) is an understudied rare disease that should be taken into account in the differential diagnosis of therapy-resistant bronchial obstruction combined with focal pulmonary lesions and mosaic attenuation on chest CT. The aim of this article is to discuss the aspects of clinical and morphological diagnosis, therapeutic options, prognosis assessment, and the need for follow-up using a clinical case as an example. The article describes a clinical case of DIPNECH in a 55-year-old woman, and also provides a brief review of the scientific literature on DIPNECH. DIPNECH is a rare disease that most often affects non-smoking women aged around 60 years. The most frequent clinical manifestations are cough, dyspnea, stridor, and broncho-obstructive syndrome. Only histological and immunohistochemical assays can confirm the diagnosis. DIPNECH should be considered as part of the differential diagnosis in patients with prolonged cough, dyspnea of unclear genesis and changes on chest CT in the form of pulmonary focal lesions and mosaic attenuation. Conclusion. The presented clinical case shows the challenges and importance of timely diagnosis.

Lineage-specific intolerance to oncogenic drivers restricts histological transformation.

Lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC) are thought to originate from different epithelial cell types in the lung. Intriguingly, LUAD can histologically transform into SCLC after treatment with targeted therapies. In this study, we designed models to follow the conversion of LUAD to SCLC and found that the barrier to histological transformation converges on tolerance to Myc, which we implicate as a lineage-specific driver of the pulmonary neuroendocrine cell. Histological transformations are frequently accompanied by activation of the Akt pathway. Manipulating this pathway permitted tolerance to Myc as an oncogenic driver, producing rare, stem-like cells that transcriptionally resemble the pulmonary basal lineage. These findings suggest that histological transformation may require the plasticity inherent to the basal stem cell, enabling tolerance to previously incompatible oncogenic driver programs.

A multi-lesional analysis of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: a single-centre analysis

To conduct a multi-lesional computed tomography (CT) analysis of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) patients to determine volumetric changes in lesions over 5 years. A retrospective case-note review was undertaken to identify 16 patients with histological and radiological features of DIPNECH between 2012-2021. Area and volume were calculated for 17 sets of lesions identified on high-resolution CT. Clinical data were extracted from electronic patient records, which included demographic data, outpatient clinic letters, histology reports, and imaging reports. One hundred and twenty-eight lesions were identified in 16 patients (one male, 15 female) and followed-up annually over a median 1,985 days (range 1,450-2,290). At year 1 follow-up, lesion area ranged from 1-48 mm2, and lesion volume ranged from 8-18,380 mm3; lesion area ranged from 1-45mm2 and lesion volume ranged from 11-17,800 mm3 and year 5. Half (8/16) of the patients had concomitant typical carcinoid tumours and one patient had an atypical carcinoid tumour. No statistically significant correlation (p<0.05) was found between lesion cross-sectional area or volume and duration of follow-up (years and days). No metastatic spread was observed at the time of analysis. No significant increase was observed in the size of over 100 lesions in patients with DIPNECH over a 5-year period and no metastasis occurred during the study period affirming the relatively indolent course of the disease.

Congenital Pulmonary Airway Malformation Type 1 with Pulmonary Neuroendocrine Cell Hyperplasia in an Adult Male: a Rare Case Report

Abstract Introduction/Objective Congenital pulmonary airway malformations (CPAM) is rare, usually diagnosed in the pediatric population, and may occur in adults. Pulmonary neuroendocrine cell hyperplasia (PNECH) mimicking diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) associated with CPAM has not been described previously. We report a case of CPAM Type 1 with PNECH. Methods/Case Report A 33-year-old male, with past medical history of latent tuberculosis (TB) by Quantiferon blood testing, recurrent pneumonia, recurrent lung abscesses, and lung cavitary lesion for three years, presented with fever, cough with hemoptysis, shortness of breath, and left-sided chest pain. Computerized tomography of chest displayed a 10.8 cm cavitary lesion in the left lower lobe of the lung. The patient underwent left lower lobectomy of the lung. Grossly, the lobectomy specimen revealed a 10.5 cm irregular cavity communicating to the superior segmental bronchus of the left lower lobe. Microscopically, the dominant large cyst was surrounded by lung parenchyma and small cystically dilated spaces resembling bronchioles under the fibrotic pleura. The large cyst was lined by respiratory epithelium with rare pathognomonic mucous cells in clusters. Cyst walls contained smooth muscle, small islands of cartilage, and focal intense acute and chronic inflammatory cell infiltrates with hemorrhage. There were multiple foci of proliferation of pulmonary neuroendocrine cells centered around bronchioles surrounding the large cyst. The neuroendocrine cells were arranged from individual cells and cellular aggregates to larger tumorlets, highlighted by Synaptophysin and Chromogranin immunostains. No granuloma or necrosis was present. No acid-fast bacilli or fungal microorganisms were identified by special stains. The findings are consistent with CPAM type 1, with PNECH. Results (if a Case Study enter NA) NA Conclusion Our study demonstrates a histologically diagnosed adult congenital pulmonary airway malformations type 1 with an incidental pulmonary neuroendocrine cell hyperplasia, which mimics diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. To the best of our knowledge, this is the first report of such an association.

Radiological–pathological correlation in diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH): imaging and histopathology

To review histologically confirmed diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) cases and carry out a detailed pathological-radiological correlation to see if computed tomography (CT) can be used to confidently identify DIPNECH. Twenty-three histologically confirmed DIPNECH patients in the shared database of two NHS Trusts were reviewed. CT images were reviewed by two independent radiologists, each of them with >10 years of experience in thoracic imaging. All histological specimens were reviewed by a single pathologist with >25 years of experience. The diagnosis of DIPNECH was made according to the current World Health Organization (WHO) definition included in the WHO 2015 classification of pulmonary tumours. The results on histology were compared to the presence of nodules and air trapping on CT. Demographic information and, when available, molecular imaging studies and pulmonary function tests were also considered. There are prototypal clinical and radiological findings reflecting the presence of underlying histological DIPNECH: middle-aged women with multiple small and scattered nodules due to the clustering and proliferation of neuroendocrine cells. At least one larger, dominant, lung nodule reflecting a carcinoid tumour is very common and mosaic attenuation/air trapping is seen approximately in 50% of cases in inspiratory scans. Airflow obstruction is rarely associated with histological bronchial or peribronchial fibrosis, which suggests other mechanisms must be involved in its development. CT can be used to predict pathological DIPNECH in the appropriate clinical setting. It is important to consider DIPNECH to avoid overdiagnosis of more sinister conditions such as lung cancer or metastases.

Precursor lesions of lung tumors

Lung cancer is the leading cause of cancer deaths globally with many new cases diagnosed each year. Recent studies have shown that an accumulation of various genetic abnormalities results in progressive morphologic changes in bronchial epithelium. Such changes are part of the continuum from precursor lesions to invasive lung cancers. Improvement in diagnostic modalities has made the detection of such preneoplastic lesions possible and resection at this stage confer excellent prognosis. The World Health Organization (WHO) has recognized atypical adenomatous hyperplasia/ adenocarcinoma in situ, squamous dysplasia/ squamous cell carcinoma in situ, and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia as the precursor lesions of adenocarcinoma, squamous cell carcinoma, and carcinoid tumors respectively. This review summarizes the key features of these preneoplastic lesions based on the current understanding and knowledge.

THU121 Dopamine Regulates Neuroendocrine Cell Expansion In The Developing Lung

Abstract Disclosure: T. Watanabe: None. M. Stupnikov: None. Y. Zhou: None. X. Ke: None. J. Qien: None. A. Ozawa: None. M. Horigome: None. M. Yamada: None. M. Mori: None. W.V. Cardoso: None. Pulmonary neuroendocrine cells (PNECs) are rare airway epithelial cells in the lung that have function as neurosensory and endocrine cells. They arise from naive epithelial progenitor cells in mice on embryonic day (E) 12.5, migrate to branch point of proximal airway and rare found as solitary or in clusters of 5 to 20 cells termed neuroepithelial bodies (NEBs). PNECs can be aberrantly increased in a variety of human diseases, including asthma, neuroendocrine hyperplasia of infants (NEHI) and sudden infant death syndrome (SIDS). Ascl1, an Achaete-Scute family bHLH transcriptional factor is the earliest marker and master regulator of PNEC fate specification. No PNECs form in Ascl1 null mice. In an effort to identify Ascl1 downstream targets involved in PNEC specification and expansion, we performed transcriptional analysis of E14.5 lungs from Ascl1 null mouse. Gene Ontology analysis showed a number of genes associated with the catecholamine pathway downregulated in mutants, compared to WT. These included tyrosine hydroxylase (Th) dopa decarboxylase (Ddc), dopamine beta-hydroxylase (Dβh). To gain initial insights into how catecholamine signaling influence PNEC development, we cultured E12.5 lung explants with various inhibitors of the catecholamine biosynthesis pathway and examined the effects on cell differentiation and proliferation. Treatment with Metyrosine (Met) and Benserazide (Benz) which inhibits dopamine production, resulted in a striking increase in PNEC number in NEBs as seen by expansion in Ascl1+ cells, without affecting cell proliferation. By contrast, no effect was observed with Zamicastat (Zami) which inhibits norepinephrine production. To examine whether dopamine regulated PNEC differentiation, we used the D1-like receptor antagonist, SCH-23390 and the D2-like receptor antagonist, Haloperidol in lung explant cultures, as before. Only Haloperidol increased PNECs in cultured lungs. This effect was similarly observed by maternal administration of Haloperidol intraperitoneally from E9.5 to 13.5 and analysis of harvested embryos at E14.5 and 18.5. Current studies mapping expression of other components of the dopamine pathway in the developing airway epithelium suggests a complex interaction of PNECs with neighbor cells in the regulation of the proper number of NEBs and solitary NE cells. These observations may provide a link between catecholamine signaling and aberrant PNEC behavior in the pathogenesis of human conditions affecting these cells. Presentation: Thursday, June 15, 2023

DIPNECH: pragmatic approach, uncertainties, notable associations, and a proposal for an improved definition.

DIPNECH is an increasingly recognized entity that primarily affects middle-aged and elderly women. It is characterized by abnormal proliferation of pulmonary neuroendocrine cells (PNECs) and considered a preinvasive lesion for carcinoid tumorlets/tumors. Sometimes, DIPNECH is accompanied by constrictive bronchiolitis which usually manifests as chronic cough and/or dyspnea, along with airflow limitation on spirometry. The telltale imaging sign of DIPNECH is the presence of multiple noncalcified pulmonary nodules and mosaic attenuation on CT. However, these clinico-radiologic features of DIPNECH are characteristic but nonspecific; thus, histopathologic confirmation is usually necessary. DIPNECH has an indolent course, and only rarely leads to respiratory failure or death; progression to overt neuroendocrine tumor (carcinoid) of the lung occurs in a minority of patients. Of available therapies, somatostatin analogs and mTOR inhibitors are most promising. In this review, we provide an update regarding the diagnosis and management of DIPNECH and describe critical gaps in our understanding of this entity, including the central terms "diffuse" and "idiopathic". We also summarize the inconsistencies in definitions employed by recent studies and discuss the pitfalls of the DIPNECH definitions proposed by the World Health Organization in 2021. In this context, we propose an objective and reproducible radio-pathologic case definition intended for implementation in the research realm and seeks to enhance homogeneity across cohorts. Furthermore, we discuss aspects of PNECs biology which suggest that PNEC hyperplasia may contribute to the pathogenesis of phenotypes of lung disease aside from constrictive bronchiolitis and carcinoid tumorlets/tumors. Finally, we steer attention to some of the most pressing and impactful research questions awaiting to be unraveled.

Alcohol-mediated susceptibility to lung fibrosis is associated with group 2 innate lymphoid cells in mice.

Chronic alcohol ingestion promotes acute lung injury and impairs immune function. However, the mechanisms involved are incompletely understood. Here, we show that alcohol feeding enhances bleomycin-induced lung fibrosis and inflammation via the regulation of type 2 innate immune responses, especially by group 2 innate lymphoid cells (ILC2s). Neuroimmune interactions have emerged as critical modulators of lung inflammation. We found alcohol consumption induced the accumulation of ILC2 and reduced the production of the neuropeptide calcitonin gene-related peptide (CGRP), primarily released from sensory nerves and pulmonary neuroendocrine cells (PNECs). CGRP potently suppressed alcohol-driven type 2 cytokine signals in vivo. Vagal ganglia TRPV1+ afferents mediated immunosuppression occurs through the release of CGRP. Inactivation of the TRPV1 receptor enhanced bleomycin-induced fibrosis. In addition, mice lacking the CGRP receptor had the increased lung inflammation and fibrosis and type 2 cytokine production as well as exaggerated responses to alcohol feeding. Together, these data indicate that alcohol consumption regulates the interaction of CGRP and ILC2, which is a critical contributor of lung inflammation and fibrosis.

Regionally distinct progenitor cells in the lower airway give rise to neuroendocrine and multiciliated cells in the developing human lung

Using scRNA-seq and microscopy, we describe a cell that is enriched in the lower airways of the developing human lung and identified by the unique coexpression of SCGB3A2/SFTPB/CFTR. To functionally interrogate these cells, we apply a single-cell barcode-based lineage tracing method, called CellTagging, to track the fate of SCGB3A2/SFTPB/CFTR cells during airway organoid differentiation in vitro. Lineage tracing reveals that these cells have a distinct differentiation potential from basal cells, giving rise predominantly to pulmonary neuroendocrine cells and a subset of multiciliated cells distinguished by high C6 and low MUC16 expression. Lineage tracing results are supported by studies using organoids and isolated cells from the lower noncartilaginous airway. We conclude that SCGB3A2/SFTPB/CFTR cells are enriched in the lower airways of the developing human lung and contribute to the epithelial diversity and heterogeneity in this region.

DNA methylation in small cell lung cancer

AbstractSmall cell lung cancer (SCLC) originates from pulmonary neuroendocrine cells and accounts for approximately 15% of lung cancer incidents. Patients with SCLC have a very low survival rate due to fast progression and early metastasis. Despite the recent approval of immune checkpoint blockade for treatment of SCLC by US FDA, conventional platinum chemotherapy remains the first‐line treatment which always develops quick drug resistance. To define targets for diagnosis and treatment, SCLC has been categorized by different molecular markers. The most popular markers include genomic mutations in tumour suppressor genes such as TP53 and RB1 and expression of lineage‐specific transcription factors (TFs), that is ASCL1, NEUROD1, POU2F3 and YAP1. As DNA methylation is an important hallmark of cancer, efforts were made to investigate the mechanisms of DNA methylation involved in SCLC progression. Indeed, SCLC has distinct pattern of DNA methylation due to its different features compared to non‐SCLC and other tumours. In this review, we summarized the mechanisms of DNA methylation in SCLC which are associated with lineage‐specific TFs, cell proliferation, anti‐apoptosis, drug resistance, immune evasion and metastasis. We foresaw the challenges of applying DNA methylation in clinical diagnosis and treatment and discussed new approaches and technologies to overcome them. Combined with other gene regulatory information such as transcription and histone modification, DNA methylation/hydroxymethylation in SCLC will be resolved at single‐cell resolution to dissect the tumour microenvironment. The huge multiomics data will be processed and integrated with clinical data such as clinical images and pathological histochemistry by artificial intelligence and cloud computing. Circulating cell‐free DNA methylation will greatly enhance early diagnosis and prognosis prediction. New organoid and organ chip models will break through the obstacles of sampling limitation, faithfully simulate the physiology of human tissues and enable examining spatiotemporal DNA methylation during SCLC progression.

Depiction of neuroendocrine features associated with immunotherapy response using a novel one-class predictor in lung adenocarcinoma

BackgroundTumours with no evidence of neuroendocrine transformation histologically but harbouring neuroendocrine features are collectively referred to as non-small cell lung cancer (NSCLC) with neuroendocrine differentiation (NED). Investigating the mechanisms underlying NED is conducive to designing appropriate treatment options for NSCLC patients.MethodsIn the present study, we integrated multiple lung cancer datasets to identify neuroendocrine features using a one-class logistic regression (OCLR) machine learning algorithm trained on small cell lung cancer (SCLC) cells, a pulmonary neuroendocrine cell type, based on the transcriptome of NSCLC and named the NED index (NEDI). Single-sample gene set enrichment analysis, pathway enrichment analysis, ESTIMATE algorithm analysis, and unsupervised subclass mapping (SubMap) were performed to assess the altered pathways and immune characteristics of lung cancer samples with different NEDI values.ResultsWe developed and validated a novel one-class predictor based on the expression values of 13,279 mRNAs to quantitatively evaluate neuroendocrine features in NSCLC. We observed that a higher NEDI correlated with better prognosis in patients with LUAD. In addition, we observed that a higher NEDI was significantly associated with reduced immune cell infiltration and immune effector molecule expression. Furthermore, we found that etoposide-based chemotherapy might be more effective in the treatment of LUAD with high NEDI values. Moreover, we noted that tumours with low NEDI values had better responses to immunotherapy than those with high NEDI values.ConclusionsOur findings improve the understanding of NED and provide a useful strategy for applying NEDI-based risk stratification to guide decision-making in the treatment of LUAD.

(857) Bilateral Lung Transplant with Recognition of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) of rhe Donor Lungs in the Immediate Postoperative Period

(857) Bilateral Lung Transplant with Recognition of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) of rhe Donor Lungs in the Immediate Postoperative Period

Novel neuroendocrine role of γ-aminobutyric acid and gastrin-releasing peptide in the host response to influenza infection

Gastrin-releasing peptide (GRP), an evolutionarily conserved neuropeptide, significantly contributes to influenza-induced lethality and inflammation in rodent models. Because GRP is produced by pulmonary neuroendocrine cells (PNECs) in response to γ-aminobutyric acid (GABA), we hypothesized that influenza infection promotes GABA release from PNECs that activate GABAB receptors on PNECs to secrete GRP. Oxidative stress was increased in the lungs of influenza A/PR/8/34 (PR8)-infected mice, as well as serum glutamate decarboxylase 1, the enzyme that converts L-glutamic acid into GABA. The therapeutic administration of saclofen, a GABAB receptor antagonist, protected PR8-infected mice, reduced lung proinflammatory gene expression of C-C chemokine receptor type 2 (Ccr2), cluster of differentiation 68 (Cd68), and Toll like receptor 4 (Tlr4) and decreased the levels of GRP and high-mobility group box 1 (HMGB1) in sera. Conversely, baclofen, a GABAB receptor agonist, significantly increased the lethality and inflammatory responses. The GRP antagonist, NSC77427, as well as the GABAB antagonist, saclofen, blunted the PR8-induced monocyte infiltration into the lung. Together, these data provide the first report of neuroregulatory control of influenza-induced disease.

Distinct roles for SOX2 and SOX21 in differentiation, distribution and maturation of pulmonary neuroendocrine cells

Pulmonary neuroendocrine (NE) cells represent a small population in the airway epithelium, but despite this, hyperplasia of NE cells is associated with several lung diseases, such as congenital diaphragmatic hernia and bronchopulmonary dysplasia. The molecular mechanisms causing the development of NE cell hyperplasia remains poorly understood. Previously, we showed that the SOX21 modulates the SOX2-initiated differentiation of epithelial cells in the airways. Here, we show that precursor NE cells start to develop in the SOX2 + SOX21 + airway region and that SOX21 suppresses the differentiation of airway progenitors to precursor NE cells. During development, clusters of NE cells start to form and NE cells mature by expressing neuropeptide proteins, such as CGRP. Deficiency in SOX2 resulted in decreased clustering, while deficiency in SOX21 increased both the numbers of NE ASCL1 + precursor cells early in development, and the number of mature cell clusters at E18.5. In addition, at the end of gestation (E18.5), a number of NE cells in Sox2 heterozygous mice, did not yet express CGRP suggesting a delay in maturation. In conclusion, SOX2 and SOX21 function in the initiation, migration and maturation of NE cells.

Involvement of Epithelial-Mesenchymal Transition Genes in Small Cell Lung Cancer Phenotypic Plasticity.

Small cell lung cancer (SCLC) is an aggressive cancer recalcitrant to treatment, arising predominantly from epithelial pulmonary neuroendocrine (NE) cells. Intratumor heterogeneity plays critical roles in SCLC disease progression, metastasis, and treatment resistance. At least five transcriptional SCLC NE and non-NE cell subtypes were recently defined by gene expression signatures. Transition from NE to non-NE cell states and cooperation between subtypes within a tumor likely contribute to SCLC progression by mechanisms of adaptation to perturbations. Therefore, gene regulatory programs distinguishing SCLC subtypes or promoting transitions are of great interest. Here, we systematically analyze the relationship between SCLC NE/non-NE transition and epithelial to mesenchymal transition (EMT)-a well-studied cellular process contributing to cancer invasiveness and resistance-using multiple transcriptome datasets from SCLC mouse tumor models, human cancer cell lines, and tumor samples. The NE SCLC-A2 subtype maps to the epithelial state. In contrast, SCLC-A and SCLC-N (NE) map to a partial mesenchymal state (M1) that is distinct from the non-NE, partial mesenchymal state (M2). The correspondence between SCLC subtypes and the EMT program paves the way for further work to understand gene regulatory mechanisms of SCLC tumor plasticity with applicability to other cancer types.

Pulmonary Function Tests as a Biomarker in Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia Patients Treated With Somatostatin Analogues.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) describes an indolent, under-recognised and poorly understood pulmonary condition with fewer than 200 reported cases across the literature. Currently, cases are diagnosed following a biopsy of the primary lesion, with treatment options centring on symptomatic benefit as opposed to targeting the underlying aetiology. Classically, DIPNECH lesions have been described as slow growing and benign, but with growing awareness of the condition, reports of metastatic disease with significant symptomatic burden have been reported. However, effectively addressing the subset of DIPNECH patients with greater metastatic potential remains an unmet clinical need. Due to the similarities between DIPNECH and carcinoid patients, several centres have considered using somatostatin analogues to not only help symptomatically but also to initiate tumour regression. However, to date, there are limited biomarkers to help evaluate the benefit of such options. In this review, we consider the use of pulmonary function tests (PFTs) to help quantify the benefit of somatostatin analogues. Although much of the evidence stems from small single-centre studies, the use of PFTs within the treatment pathway for both localised and metastatic DIPNECH represents a meaningful improvement from subjective monitoring of disease.

Plasma Progastrin-Releasing Peptide and Chromogranin A Assays for Diagnosing and Monitoring Lung Well-Differentiated Neuroendocrine Tumors: A Brief Report

IntroductionThe use of chromogranin A (CGA) as a circulating biomarker in lung carcinoids (LCs) is limited by low specificity and sensitivity. This study aimed to evaluate plasma progastrin-releasing peptide (ProGRPp) as an alternative to plasma CGA (CGAp), for the diagnosis and follow-up of LC. MethodsProGRPp and CGAp concentrations were measured in 107 patients with LC and 105 patients with benign lung disease (BLD). ResultsProGRPp distinguished patients with LC with active disease in the pretreatment (n = 43) and post-treatment (n = 43) groups from those with BLD: area under the curve for both 0.864 (p < 0.0001); sensitivity 67.4% and 58.1%, respectively; specificity 96.2%; at 64 pg/mL cutoff. CGAp failed to differentiate both LC groups from those with BLD: area under the curve 0.579 and 0.526 (for both p > 0.1); sensitivity 34.9% and 25.6%, respectively; specificity 73.3%; at 104 ng/mL cutoff. Only ProGRPp correlated with the Ki67 proliferation index (r = 0.40, p < 0.001) and was associated with mitotic count (p = 0.025), stage (p = 0.018), grade (p = 0.019), and the expression of thyroid transcription factor-1 (p = 0.005). ProGRPp had a high sensitivity (92.3%) in LC with diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. Abnormal postoperative ProGRPp level was associated with residual disease (p = 0.029). The changes in ProGRPp level during treatment, a decrease greater than 30% and an increase greater than 8%, were associated with image-based outcomes, partial response and disease progression, respectively (p < 0.0001). CGAp did not reflect the disease course. ConclusionsProGRPp was superior to CGAp in diagnosing LC with correlations concerning proliferation, grading, staging, diffuse idiopathic pulmonary neuroendocrine cell hyperplasia co-occurrence, and response to treatment. ProGRPp is an optimal emerging biomarker to be further evaluated.