Treatment of pulmonary neuroendocrine tumours: state of the art and future developments

Diagnostic Anatomic Imaging for Neuroendocrine Neoplasms: Maximizing Strengths and Mitigating Weaknesses

ABSTRACT

Neuroendocrine neoplasms are a heterogeneous group of gastrointestinal and lung tumors. Their diverse clinical manifestations, variable locations, and heterogeneity present notable diagnostic challenges. This article delves into the imaging modalities vital for their detection and characterization. Computed tomography is essential for initial assessment and staging. At the same time, magnetic resonance imaging (MRI) is particularly adept for liver, pancreatic, osseous, and rectal imaging, offering superior soft tissue contrast. The article also highlights the limitations of these imaging techniques, such as MRI's inability to effectively evaluate the cortical bone and the questioned cost-effectiveness of computed tomography and MRI for detecting specific gastric lesions. By emphasizing the strengths and weaknesses of these imaging techniques, the review offers insights into optimizing their utilization for improved diagnosis, staging, and therapeutic management of neuroendocrine neoplasms.

A Comprehensive Review on Neuroendocrine Neoplasms: Presentation, Pathophysiology and Management

Neuroendocrine neoplasms (NENs) are a group of heterogeneous tumors with neuroendocrine differentiation that can arise from any organ. They account for 2% of all malignancies in the United States. A significant proportion of NEN patients experience endocrine imbalances consequent to increased amine or peptide hormone secretion, impacting their quality of life and prognosis. Over the last decade, pathologic categorization, diagnostic techniques and therapeutic choices for NENs-both well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs)-have appreciably evolved. Diagnosis of NEN mostly follows a suspicion from clinical features or incidental imaging findings. Hormonal or non-hormonal biomarkers (like serum serotonin, urine 5-HIAA, gastrin and VIP) and histology of a suspected NEN is, therefore, critical for both confirmation of the diagnosis and classification as an NET or NEC. Therapy for NENs has progressed recently based on a better molecular understanding, including the involvement of mTOR, VEGF and peptide receptor radionuclide therapy (PRRT), which add to the growing evidence supporting the possibility of treatment beyond complete resection. As the incidence of NENs is on the rise in the United States and several other countries, physicians are more likely to see these cases, and their better understanding may support earlier diagnosis and tailoring treatment to the patient. We have compiled clinically significant evidence for NENs, including relevant changes to clinical practice that have greatly updated our diagnostic and therapeutic approach for NEN patients.

Clinic and genetic similarity assessments of atypical carcinoid, neuroendocrine neoplasm with atypical carcinoid morphology and elevated mitotic count and large cell neuroendocrine carcinoma

Background

Pulmonary neuroendocrine neoplasms can be divided into typical carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma, and small cell (lung) carcinoma. According to the World Health Organization, these four neoplasms have different characteristics and morphological traits, mitotic counts, and necrotic status. Importantly, “a grey-zone” neoplasm with an atypical carcinoid-like morphology, where the mitotic rate exceeds the criterion of 10 mitoses per 2 mm², have still not been well classified. In clinical practice, the most controversial area is the limit of 11 mitoses to distinguish between atypical carcinoids and large cell neuroendocrine carcinomas.

Methods

Basic and clinical information was obtained from patient medical records. A series of grey-zone patients (n = 8) were selected for exploring their clinicopathological features. In addition, patients with atypical carcinoids (n = 9) and classical large cell neuroendocrine carcinomas (n = 14) were also included to compare their similarity to these neoplasms with respect to tumour morphology and immunohistochemical staining.

Results

We found that these grey-zone tumour sizes varied and affected mainly middle-aged and older men who smoked. Furthermore, similar gene mutations were found in the grey-zone neoplasms and large cell neuroendocrine carcinomas, for the mutated genes of these two are mainly involved in PI3K-Akt signal pathways and Pathways in cancer, including a biallelic alteration of TP53/RB1 and KEAP1.

Conclusions

Our findings indicate that neuroendocrine neoplasm with atypical carcinoid morphology and elevated mitotic counts is more similar to large cell neuroendocrine carcinoma than atypical carcinoid. Furthermore, this study may help improve diagnosing these special cases in clinical practice to avoid misdiagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09391-w.

Role of filamin A in the pathogenesis of neuroendocrine tumors and adrenal cancer

Cell cytoskeleton proteins are involved in tumor pathogenesis, progression and pharmacological resistance. Filamin A (FLNA) is a large actin-binding protein with both structural and scaffold functions implicated in a variety of cellular processes, including migration, cell adhesion, differentiation, proliferation and transcription. The role of FLNA in cancers has been studied in multiple types of tumors. FLNA plays a dual role in tumors, depending on its subcellular localization, post-translational modification (as phosphorylation at Ser2125) and interaction with binding partners. This review summarizes the experimental evidence showing the critical involvement of FLNA in the complex biology of endocrine tumors. Particularly, the role of FLNA in regulating expression and signaling of the main pharmacological targets in pituitary neuroendocrine tumors, pancreatic neuroendocrine tumors, pulmonary neuroendocrine tumors and adrenocortical carcinomas, with implications on responsiveness to currently used drugs in the treatment of these tumors, will be discussed.

Peptide Receptor Radionuclide Therapy of Pulmonary Neuroendocrine Neoplasms: a Single-Centre Experience

Purpose

Peptide receptor radionuclide therapy represents a therapeutic option for neuroendocrine neoplasms; to date, experiences with peptide receptor radionuclide therapy of pulmonary neuroendocrine neoplasms are still limited. We report our experience with peptide receptor radionuclide therapy of pulmonary neuroendocrine neoplasm patients.

Materials and Methods

Clinical records of 14 pulmonary neuroendocrine neoplasm patients (7 female and 7 male) who received at least 2 cycles of peptide receptor radionuclide therapy were retrospectively reviewed. Tumoural uptake of somatostatin analogues at pre-treatment imaging was graded as 2 to 3 in all patients. RECIST criteria were used to evaluate response.

Results

No treated patient had significant toxicity. Partial response was found in 3 (21.4%) patients, stable disease in 7 (50%), and progressive disease in 4 (28.6%). A statistically significant difference between disease state at enrolment and after peptide receptor radionuclide therapy was found.

Conclusions

Our data furtherly support peptide receptor radionuclide therapy as a safe and effective treatment of patients affected by pulmonary neuroendocrine neoplasms allowing disease control in about 71% of patients without showing significant toxicity. Other studies are needed to confirm our results.

Morphologic and molecular classification of lung neuroendocrine neoplasms

Neuroendocrine neoplasms (NENs) of the lung encompass neuroendocrine tumors (NETs) composed of typical (TC) and atypical (AC) carcinoids and full-fledged carcinomas (NECs) inclusive of large cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCLC). NETs and NECs are thought to represent distinct and separate lesions with neither molecular overlap nor common developmental continuum. Two perspectives were addressed regarding the morphologic and molecular classification of lung NENs: (i) a supervised approach by browsing the traditional classification, the relevant gene alterations, and their clinical implications; and (ii) an unsupervised approach, by reappraising neoplasms according to risk factors and natural history of disease to construct an interpretation model relied on biological data. We herein emphasize lights and shadows of the current classification of lung NENs and provide an alternative outlook on these tumors focused on what we currently know about the biological determinants and the natural history of disease.

[Surgery of tracheobronchial carcinoid tumours: Activity report]

INTRODUCTION

Our purpose is to evaluate our results of surgery for tracheobronchial carcinoid tumour as well as the long-term survival.

METHODS

This is a retrospective and descriptive study performed in the department of thoracic surgery of CHU Hassan II (Marocco) over a period of 9 years. It concerns all patients with a tracheal or bronchial carcinoid tumour who underwent surgery.

RESULTS

Twenty-three patients with a mean age of 39 years were operated on for 24 carcinoid tumours. The sex ratio was 0.29. The diagnostic delay ranged from 3 months to 8 years and the main symptom was haemoptysis in 74% of cases (n=17). The tumour was localized in the right bronchial tree in 70% of cases (n=16). The procedures performed were tracheal resection and end-to-end anastomosis in 1 case, lobectomy in 12 cases including 3 sleeve lobectomies, bilobectomy of middle and lower lobes in 7 cases and pneumonectomy in 4 cases. The prognosis was favourable in 91% after an average follow-up of 29 months.

CONCLUSIONS

Surgery remains the only curative therapeutic option for tracheobronchial carcinoid tumours with acceptable morbidity and mortality.

Diagnostic and Management Pathways for Pulmonary Carcinoid Tumours in the United Kingdom: Results from the National Lung Neuroendocrine Tumour Pathway Project

There is inconsistency among published guidelines for the optimal diagnostic and management pathways for patients with typical (TC) or atypical (AC) pulmonary carcinoid tumours. We conducted a UK-wide clinician survey to assess current practice for the diagnosis, management, and follow-up of patients with TC/AC and descriptively compared management between European Neuroendocrine Tumor Society (ENETS) accredited centres of excellence (CoE) and nonaccredited centres (non-CoE). Twenty-seven clinicians (10 CoE; 17 non-CoE) participated. Computed tomography of thorax, abdomen, and pelvis was the most commonly reported diagnostic tool (96% of respondents), and bone scans and gallium somatostatin receptor scintigraphy positron emission tomography (SRS PET) were the least commonly reported (30% and 37% of respondents, respectively). Adjuvant therapy is considered for resected TC/AC by <5% of respondents for patients with stage N0 M0 AC or TC, up to 48% of respondents for patients with AC with R1 disease. Somatostatin analogues were the most commonly reported first-line treatment (63% of respondents), and chemotherapy was the most commonly reported second-line therapy and third-line therapy (33% and 41%, respectively) for unresectable and metastatic disease. Reported frequency of initial follow-up after primary surgery ranged from every 2 months to annual, and total follow-up duration ranged from 2 years to indefinite depending on disease type (TC/AC) and stage. For most diagnostic investigations, the highest reported frequency of use was in CoE, most notably gallium SRS PET (70% CoE vs. 18% non-CoE respondents). 93% of respondents (100% CoE; 88% non-CoE) reported having neuroendocrine tumour- (NET-) specialist multidisciplinary team meetings at their centre; 59% (90% CoE; 41% non-CoE) had a NET Clinical Nurse Specialist (CNS) and 48% (80% CoE; 29% non-CoE) had a lung NET patient database. The survey results suggest variability between UK centres in diagnostic pathways and management of patients with TC/AC and suggest that CoE may be able to offer an improved service to patients.

Epithelial cell plasticity defines heterogeneity in lung cancer

Lung cancer is the leading cause of cancer death for both men and women and accounts for almost 18.4% of all deaths due to cancer worldwide, with the global incidence increasing by approximately 0.5% per year. Lung cancer is regarded as a devastating type of cancer owing to its high prevalence, reduction in the health-related quality of life, frequently delayed diagnosis, low response rate, high toxicity, and resistance to available therapeutic options. The highly heterogeneous nature of this cancer with a proximal-to-distal distribution throughout the respiratory tract dramatically affects its diagnostic and therapeutic management. The diverse composition and plasticity of lung epithelial cells across the respiratory tract are regarded as significant factors underlying lung cancer heterogeneity. Therefore, definitions of the cells of origin for different types of lung cancer are urgently needed to understand lung cancer biology and to achieve early diagnosis and develop cell-targeted therapies. In the present review, we will discuss the current understanding of the cellular and molecular alterations in distinct lung epithelial cells that result in each type of lung cancer.

Molecular heterogeneity in lung cancer: from mechanisms of origin to clinical implications

Molecular heterogeneity is a frequent event in cancer responsible of several critical issues in diagnosis and treatment of oncologic patients. Lung tumours are characterized by high degree of molecular heterogeneity associated to different mechanisms of origin including genetic, epigenetic and non-genetic source. In this review, we provide an overview of recognized mechanisms underlying molecular heterogeneity in lung cancer, including epigenetic mechanisms, mutant allele specific imbalance, genomic instability, chromosomal aberrations, tumor mutational burden, somatic mutations. We focus on the role of spatial and temporal molecular heterogeneity involved in therapeutic implications in lung cancer patients.

Recent advances in the molecular landscape of lung neuroendocrine tumors

INTRODUCTION

Neuroendocrine tumors of the lung (Lung-NETs) make up a heterogenous family of neoplasms showing neuroendocrine differentiation and encompass carcinoids and neuroendocrine carcinomas. On molecular grounds, they considered two completely distinct and separate tumor groups with no overlap of molecular alterations nor common developmental mechanisms. Areas covered: Two perspectives were evaluated based on an extensive review and rethinking of literature: (1) the current classification as an instrument to obtaining clinical and molecular insights into the context of Lung-NETs; and (2) an alternative and innovative interpretation of these tumors, proposing a tripartite separation into early aggressive primary high-grade neuroendocrine tumors (HGNET), differentiating or secondary HGNET, and indolent NET. Expert opinion: We herein provide an alternative outlook on Lung-NETs, which is a paradigm shift to current pathogenesis models and expands the understanding of these tumors.

Clinicopathological characteristics and prognostic factors of pulmonary large cell neuroendocrine carcinoma: A large population-based analysis

BACKGROUND

The study was conducted to compare the clinicopathological characteristics, survival outcomes, and metastatic patterns between pulmonary large cell neuroendocrine carcinoma (LCNEC) and other non-small cell lung cancer (ONSCLC), and to identify the prognostic factors of LCNEC.

METHODS

Data of patients diagnosed with LCNEC and ONSCLC from 2004 to 2014 were obtained from the Surveillance, Epidemiology, and End Results dataset. Pearson's chi-square tests were used to compare differences in clinicopathological characteristics. The Kaplan-Meier method was used for survival analysis. A propensity score was used for matching and a Cox proportional hazards model was used for multivariate and subgroup analyses.

RESULTS

A total of 2368 LCNEC cases and 231 672 ONSCLC cases were identified. LCNEC incidence increased slightly over time. Except for marital status, LCNEC patients had obviously different biological features to ONSCLC patients. Survival analysis showed that LCNEC had poorer outcomes than ONSCLC. Multivariate analysis revealed that female gender, black race, surgery, radiation, and chemotherapy were protective factors for LCNEC. Matched subgroup analysis further demonstrated that most subgroup factors favored ONSCLC, especially in early stage. Early-stage LCNEC patients had a higher risk of lung cancer-specific death than early-stage ONSCLC patients. Moreover, metastatic patterns were different between LCNEC and ONSCLC. LCNEC patients with isolated liver metastasis or combined invasion to other organs had poorer survival rates.

CONCLUSIONS

LCNEC has totally different clinicopathological characteristics and metastatic patterns to ONSCLC. LCNEC also has poorer survival outcomes, primarily because of isolated liver metastasis or combined invasion to other organs. Most subgroup factors are adverse factors for LCNEC.

[Systemic Therapy for Low-grade Pulmonary Neuroendocrine Tumor]

肺部是神经内分泌肿瘤（neuroendocrine tumor, NET）的第二好发部位。肺类癌包括典型类癌和不典型类癌，属于低级别神经内分泌肿瘤。这一类肿瘤由于发病率较低，目前尚未得到广大医务工作者的重视。但有效的治疗不仅能提高患者的远期生存，还能控制患者症状，改善生活质量。本文分别阐述肺低级别神经内分泌肿瘤的流行病学和病理学特点、早期患者的治疗策略以及进展期患者的治疗策略。早期患者应当尽早进行手术治疗。进展期患者治疗方式包括化疗、SSAs、mTOR抑制剂、肽受体介导的放射性核素治疗、生物治疗以及靶向治疗。目前的研究结论大多来自其他部位的NETs研究外推而来，仍需针对肺低级别神经内分泌肿瘤患者进行特异性临床试验加以证实。

Lung and Thymic Carcinoids

Carcinoids of the lung and thymus are rare thoracic cancers. In general, lung carcinoid tumors have a favorable prognosis, particularly when diagnosed at an early stage and treated with surgical resection. Thymic neuroendocrine tumors may be associated with multiple endocrine neoplasia-1 syndrome, tend to have a more aggressive natural history, and relatively frequently secrete ectopic adrenocorticotropic hormone.

PD-L1 expression in large cell neuroendocrine carcinoma of the lung

OBJECTIVES

Large cell neuroendocrine carcinoma of the lung (LCNEC) is associated with an unfavorable prognosis and only few patients are eligible for surgery. In most patients, chemotherapy is recommended alone or in addition to resection. Novel immunotherapies blocking the PD-L1 pathway have been introduced into therapeutic regimens for NSCLC with great success. In order to evaluate a possible efficacy of an anti-PD-L1 therapy, we analyzed the frequency of PD-L1 expression in LCNEC.

MATERIAL AND METHODS

We retrospectively reviewed data from 76 patients with LCNEC treated in our institution between 1998 and 2010. The expression of PD-L1 was examined on the tumor cells and the tumor surrounding tissue by immunohistochemistry. An expression of >1% was considered as positive. Statistical analysis was performed to determine significant predictors for survival.

RESULTS

56 of 76 patients with LCNEC were treated with a potentially therapeutic surgical approach. Tumor-specific survival (TSS) of the entire cohort was 29% at five years. 17 patients (22.3%) had PD-L1 positive tumors and 12 of these had no additional PD-L1 expression in the adjacent immune cell infiltrate. Tumor-flanking immune cells were found PD-L1 positive 28 patients; 16 of these had no additional expression on the tumor cells. The most considerable difference in survival was found when comparing patients with isolated PD-L1 expression on tumor cells and PD-L1 negative immune cell infiltrate to their counterpart (positive immune-cell infiltrate and PD-L1 negative tumor cell surface; 5-year TSS: 0% vs. 60%; p < 0.017).

CONCLUSION

PD-L1 expression in LCNEC was associated with poorer survival whereas PD-L1 expression in the tumor microenvironment seemed to have a beneficial effect. Therapeutic approaches have to be evaluated in future.

Processing Escape Mechanisms Through Altered Proteasomal Cleavage of Epitopes Affect Immune Response in Pulmonary Neuroendocrine Tumors

Background:

Immunotherapy, especially immune checkpoint inhibition, is one of the most sophisticated approaches in cancer therapy. Immune checkpoint inhibition has already been successfully applied for treatment of non-small cell lung cancer and various other entities. Unfortunately, 60% of the cases show signs of therapy resistance. Additionally, a proportion of cases shows initial insensitivity to immune checkpoint inhibition. We consider a novel escape mechanism in association with deficient proteasomal epitope processing to be one prominent reason for initial insensitivity and therapy resistance. Therefore, we aim to identify mutations in association with these so-called processing escapes, in a highly diverse collective of pulmonary neuroendocrine lung tumors.

Materials and Methods:

Seventy representative tumor specimens of pulmonary neuroendocrine lung tumors were analyzed retrospectively via immunohistochemical detection of CD4, CD8, CD68, and CD20 as well as programmed cell death protein 1 and programmed cell death 1 ligand 1 for tumor immune infiltration and composition. Afterward, samples were screened for alterations in 48 genes, including 221 known mutational hotspots by massive parallel sequencing using the Illumina TruSeq Amplicon-Cancer Panel. For prediction of proteasomal cleavage probabilities, an R implementation of the machine learning tool NetChop 3.1 was utilized.

Results:

Immune cell infiltration of different compositions could be found in the majority of tumors. Deficient epitope processing was revealed to be a common event in those with steady distribution across all different subtypes. Despite immune infiltration, no significant antitumor response could be detected.

Conclusion:

Since it is widely acknowledged that tumors need to avoid the immune system to ensure their survival, processing escapes should already be present during primary tumor development. In line, processing escapes can be found in all tumors, regardless of subtype and mutational burden. Furthermore, there is solid evidence that processing escapes have a negative impact on the antitumor activity of tumor infiltrating immune cells.

Pathology Issues in Thoracic Oncology: Histologic Characterization and Tissue/Plasma Genotyping May Resolve Diagnostic Dilemmas

Lung cancer is a heterogeneous diagnosis that encompasses a spectrum of histologic and molecular subgroups. A paradigm shift favoring selection of treatment based on histologic and molecular makeup has positively affected prognosis for patients with metastatic lung cancer, with select patients experiencing durable responses to treatment. However, prognosis remains poor for the majority of patients. Furthermore, oncologists are increasingly faced with challenging dilemmas related to histopathologic and molecular characterization of tumors, both at diagnosis and during treatment. In this review, we focus on three particular challenges: (1) management of mixed histology tumors, a particularly aggressive group of lung cancers, (2) distinguishing multiple primary lung tumors from intrapulmonary metastases, and (3) incorporation of liquid biopsies into the diagnostic algorithm and subsequent follow-up of patients with advanced lung cancer. This review will summarize the existing literature and highlight the potential for molecular genotyping to help refine approaches to each of these challenges.

Classification of pulmonary neuroendocrine tumors: new insights

Neuroendocrine tumors of the lung (Lu-NETs) embrace a heterogeneous family of neoplasms classified into four histological variants, namely typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC). Defining criteria on resection specimens include mitotic count in 2 mm2 and the presence or absence of necrosis, alongside a constellation of cytological and histological traits including cell size and shape, nuclear features and overall architecture. Clinically, TC are low-grade malignant tumors, AC intermediate-grade malignant tumors and SCLC/LCNEC high-grade malignant full-blown carcinomas with no significant differences in survival between them. Homologous tumors arise in the thymus that occasionally have some difficulties in differentiating from the lung counterparts when presented with large unresectable or metastatic lesions. Immunohistochemistry (IHC) helps refine NE diagnosis at various anatomical sites, particularly on small-sized tissue material, in which only TC and small cell carcinoma categories can be recognized easily on hematoxylin & eosin stain, while AC and LCNEC can only be suggested on such material. The Ki-67 labeling index effectively separates carcinoids from small cell carcinoma and may prove useful for the clinical management of a metastatic disease to help the therapeutic decision-making process. Although carcinoids and high-grade neuroendocrine carcinomas in the lung and elsewhere make up separate tumor categories on molecular grounds, emerging data supports the concept of secondary high-grade NETs arising in the preexisting carcinoids, whose clinical and biological relevance will have to be placed into the proper context for the optimal management of these patients. In this review, we will discuss the selected, recent literature with a focus on current issues regarding Lu-NET nosology, i.e., classification, derivation and tumor evolution.

Patient harboring a novel PIK3CA point mutation after acquired resistance to crizotinib in an adenocarcinoma with ROS1 rearrangement: A case report and literature review

ROS1 rearrangement occurs in 1–2% of non‐small cell lung cancer (NSCLC) cases. These patients would benefit from treatment with the anaplastic lymphoma kinase inhibitor, crizotinib; however, resistance to crizotinib inevitably develops in such patients despite an initial response. The mechanism of acquired resistance to crizotinib in patients with NSCLC with ROS1 rearrangement has not yet been identified. Herein, we report a case of a 66‐year‐old woman diagnosed with adenocarcinoma. PCR revealed no EGFR or ALK mutations. After the patient underwent several rounds of chemotherapy, crizotinib was administered. The disease explosively progressed six months later. A novel PIK3CA gene point mutation (p.L531P) was detected by next generation sequencing. This case is the second report of bypass activation conferred crizotinib resistance in a patient with NSCLC with ROS1‐rearrangement, but is the first to confirm that activation of the mTOR signaling pathway leads to acquired crizotinib resistance.

FLNA is implicated in pulmonary neuroendocrine tumors aggressiveness and progression

Pulmonary neuroendocrine tumors (PNTs) comprise different neoplasms, ranging from low grade carcinoids to the highly malignant small cell lung cancers. Several studies identified the cytoskeleton protein Filamin A (FLNA) as determinant in cancer progression and metastasis, but the role of FLNA in PNT aggressiveness and progression is still unknown.

We evaluated FLNA expression in PNTs with different grade of differentiation, the role of FLNA in cell proliferation, colony formation, angiogenesis, cell adhesion and migration in PNT cell line (H727 cells) and primary cultures and the possible interaction between FLNA and Rap1-GTPase. FLNA is highly expressed in PNTs with high malignant grade. FLNA silencing reduces cyclin D1 levels (-51±5, p<0.001) and cell proliferation in PNT cells (-37±4, p<0.05), colony formation and VEGF expression (-39±9%, p<0.01) in H727 cells.

FLNA and Rap1 co-localize in cellular protrusions and FLNA silencing up-regulates Rap1 expression (+73±18%, p<0.01).

Rap1 silencing prevents cell adhesion increase (+43%±18%, p<0.01) and cell migration decrease (-56±7%, p<0.01) induced by FLNA silencing, without affecting cell proliferation reduction. In conclusion, FLNA is implicated in PNT progression, in part through Rap1, thus providing a potential diagnostic and therapeutic target.

Lung neuroendocrine tumours: deep sequencing of the four World Health Organization histotypes reveals chromatin-remodelling genes as major players and a prognostic role for TERT, RB1, MEN1 and KMT2D

Next-generation sequencing (NGS) was applied to 148 lung neuroendocrine tumours (LNETs) comprising the four World Health Organization classification categories: 53 typical carcinoid (TCs), 35 atypical carcinoid (ACs), 27 large-cell neuroendocrine carcinomas, and 33 small-cell lung carcinomas. A discovery screen was conducted on 46 samples by the use of whole-exome sequencing and high-coverage targeted sequencing of 418 genes. Eighty-eight recurrently mutated genes from both the discovery screen and current literature were verified in the 46 cases of the discovery screen, and validated on additional 102 LNETs by targeted NGS; their prevalence was then evaluated on the whole series. Thirteen of these 88 genes were also evaluated for copy number alterations (CNAs). Carcinoids and carcinomas shared most of the altered genes but with different prevalence rates. When mutations and copy number changes were combined, MEN1 alterations were almost exclusive to carcinoids, whereas alterations of TP53 and RB1 cell cycle regulation genes and PI3K/AKT/mTOR pathway genes were significantly enriched in carcinomas. Conversely, mutations in chromatin-remodelling genes, including those encoding histone modifiers and members of SWI-SNF complexes, were found at similar rates in carcinoids (45.5%) and carcinomas (55.0%), suggesting a major role in LNET pathogenesis. One AC and one TC showed a hypermutated profile associated with a POLQ damaging mutation. There were fewer CNAs in carcinoids than in carcinomas; however ACs showed a hybrid pattern, whereby gains of TERT, SDHA, RICTOR, PIK3CA, MYCL and SRC were found at rates similar to those in carcinomas, whereas the MEN1 loss rate mirrored that of TCs. Multivariate survival analysis revealed RB1 mutation (p = 0.0005) and TERT copy gain (p = 0.016) as independent predictors of poorer prognosis. MEN1 mutation was associated with poor prognosis in AC (p = 0.0045), whereas KMT2D mutation correlated with longer survival in SCLC (p = 0.0022). In conclusion, molecular profiling may complement histology for better diagnostic definition and prognostic stratification of LNETs. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Ki-67 labeling index of neuroendocrine tumors of the lung has a high level of correspondence between biopsy samples and surgical specimens when strict counting guidelines are applied

Optimal histopathological analysis of biopsies from metastases of neuroendocrine tumor (NET) of the lung requires more than morphology only. Additional parameters such as Ki-67 labeling index are required for adequate diagnosis, but few studies have compared reproducibility of different counting protocols and modalities of reporting on biopsies of lung NET. We compared the results of four different manual counting techniques to establish Ki-67 LI. On 47 paired biopsies and surgical specimens from 22 typical carcinoids (TCs), 14 atypical carcinoids (ACs), six large cell neuroendocrine carcinomas (LCNECs), and five small cell carcinomas (SCCs) immunohistochemical staining of Ki-67 antigen was performed. We counted, in regions of highest nuclear staining (HSR), a full ×40-high-power field (diameter = 0.55 mm), 500 or 2000 cells, or 2 mm² surface area, including the HSR or the entire biopsy fragment(s). Mitoses and necrosis were evaluated in an area of 2 mm² or the entire biopsy fragment(s). Between the four counting methods, no differences in Ki-67 LI were observed. However, a Ki-67 LI higher than 5% was found in only four cases when in an HSR, 500 cells were counted (18%), five (23%) when in an HSR 2000 cells were counted, four (18%) when 2 mm² were counted, and one (5%) TC case when the entire biopsy was counted. A 20% cutoff distinguished TC and AC from LCNEC and SCC with 100% specificity and sensitivity, while mitoses and necrosis failed to a large extent. Ki-67 LI in biopsy samples was concordant with that in resection specimens when 2000 cells, 2 mm², or the entire biopsy fragment(s) were counted. Our results are important for clinical management of patients with metastases of a lung NET.

Massive parallel sequencing and digital gene expression analysis reveals potential mechanisms to overcome therapy resistance in pulmonary neuroendocrine tumors

Background: Lung cancer is the leading cause of cancer-related deaths worldwide. 25% show neuroendocrine differentiation (typical/atypical carcinoids, large-/small-cell neuroendocrine carcinomas). Carcinoids present with long survival rates, but metastatic carcinoids correlate with decreased survival and are commonly insensitive to standard chemotherapy or radiation. Therefore, novel therapeutic strategies are urgently needed.

Material and methods: 70 representative tumor specimens were used for next-generation sequencing analysis of 14 genes related to therapy response. Additionally, mRNA-expression profiles of 60 matching samples were determined for 13 selected drug targets by using the NanoString nCounter technology.

Results: A number of features known to sensitize tumors for different targeted therapies could be identified, which hopefully improve the clinical management of this subgroup of lung neoplasias. In particular, EGFR expression was observed in the investigated tumors in a noteworthy manner. Additionally, MDM2 was strongly expressed in the majority of all samples whereas the expression of its physiological inhibitor, CDKN2A, was nearly absent in all low-grade tumors. TP53 showed a high frequency of variants in high-grade tumors but mutations were rare in carcinoids.

Conclusion: Based on our results, therapeutic approaches with MDM2-inhibitors and monoclonal anti-EGFR antibodies may be promising in pulmonary carcinoid tumors.

Bronchial and Thymic Carcinoid Tumors

Bronchial and thymic carcinoids are rare. We present epidemiologic data and potential risk factors. The approach to bronchial and thymic carcinoid patients is discussed, from the initial diagnosis and evaluations to treatment. These malignancies follow staging systems of their site of origin. Because bronchial and thymic carcinoids are rare, we use many treatment strategies that have been demonstrated in gastrointestinal and pancreatic neuroendocrine tumors. The lack of information regarding efficacy in bronchial and thymic carcinoids, as well as the scarcity of therapeutic options available, demands the importance of clinical trials that include these patients.

Differential expression and tumorigenic function of neurotensin receptor 1 in neuroendocrine tumor cells

Neurotensin (NTS), localized predominantly to the small bowel, stimulates the growth of a variety of cancers, including neuroendocrine tumors (NETs), mainly through its interaction with the high-affinity NTS receptor 1 (NTSR1). Here, we observed increased expression of NTSR1 in almost all tested clinical NET samples, but not in normal tissues. Through RT-PCR analysis, we found that the expression of NTSR1 and NTSR2 was either variable (NTSR1) or absent (NTSR2) in human NET cell lines. In contrast, NTSR3 and NTS were expressed in all NET cells. Treatment with 5-aza-2′-deoxycytidine, a demethylating agent, increased levels of NTSR1 and NTSR2 suggesting that DNA methylation contributes to NTSR1/2 expression patterns, which was confirmed by methylation analyses. In addition, we found that knockdown of NTSR1 decreased proliferation, expression levels of growth-related proteins, and anchorage-independent growth of BON human carcinoid cells. Moreover, stable silencing of NTSR1 suppressed BON cell growth, adhesion, migration and invasion. Our results show that high expression of NTSR1 is found in clinical NETs and that promoter methylation is an important mechanism controlling the differential expression of NTSR1 and silencing of NTSR2 in NET cells. Furthermore, knockdown of NTSR1 in BON cells suppressed oncogenic functions suggesting that NTSR1 contributes to NET tumorigenesis.

Identification of deregulation of apoptosis and cell cycle in neuroendocrine tumors of the lung via NanoString nCounter expression analysis

Background

Neuroendocrine tumors of the lung comprise typical (TC) and atypical carcinoids (AC), large-cell neuroendocrine cancer (LCNEC) and small-cell lung cancer (SCLC). Cell cycle and apoptosis are key pathways of multicellular homeostasis and deregulation of these pathways is associated with cancerogenesis.

Materials and Methods

Sixty representative FFPE-specimens (16 TC, 13 AC, 16 LCNEC and 15 SCLC) were used for mRNA expression analysis using the NanoString technique. Eight genes related to apoptosis and ten genes regulating key points of cell cycle were investigated.

Results

ASCL1, BCL2, CASP8, CCNE1, CDK1, CDK2, CDKN1A and CDKN2A showed lower expression in carcinoids compared to carcinomas. In contrast, CCNE1 and CDK6 showed elevated expression in carcinoids compared to carcinomas. The calculated BCL2/BAX ratio showed increasing values from TC to SCLC.

Between SCLC and LCNEC CDK2, CDKN1B, CDKN2A and PNN expression was significantly different with higher expression in SCLC.

Conclusion

Carcinoids have increased CDK4/6 and CCND1 expression controlling RB1 phosphorylation via this signaling cascade. CDK2 and CCNE1 were increased in carcinomas showing that these use the opposite way to control RB1. BAX and BCL2 are antagonists in regulating apoptosis. BCL2 expression increased over BAX expression with increasing malignancy of the tumor from TC to SCLC.

SOX4, SOX11 and PAX6 mRNA expression was identified as a (prognostic) marker for the aggressiveness of neuroendocrine tumors of the lung by using next-generation expression analysis (NanoString)

BACKGROUND

Neuroendocrine tumors of the lung (NELC) account for 25% of all lung cancer cases and transcription factors may drive dedifferentiation of these tumors. This study was conducted to identify supportive diagnostic and prognostic biomarkers.

MATERIALS & METHODS

A total of 16 TC, 13 AC, 16 large cell neuroendocrine carcinomas and 15 small cell lung cancer were investigated for the mRNA expression of 11 transcription factors and related genes (MYB, MYBBP1A, OCT4, PAX6, PCDHB, RBP1, SDCBP, SOX2, SOX4, SOX11, TEAD2).

RESULTS

SOX4 (p = 0.0002), SOX11 (p < 0.0001) and PAX6 (p = 0.0002) were significant for tumor type. Elevated PAX6 and SOX11 expression correlated with poor outcome in large cell neuroendocrine carcinomas and small cell lung cancer (p < 0.0001 and p = 0.0232, respectively) based on survival data of 34 patients (57%).

CONCLUSION

Aggressiveness of NELC correlated with increasing expression of transcription factors. SOX11 seems to be a highly valuable diagnostic and prognostic marker for aggressive NELC.

Prognostic value of PD-L1 and PD-1 expression in pulmonary neuroendocrine tumors

PURPOSE

Programmed death 1 (PD-1) receptor and its ligand, programmed death ligand-1 (PD-L1), play critical roles in the immune invasion of various tumors. This study aimed to explore the clinical significance of PD-L1/PD-1 expression in the progression of pulmonary neuroendocrine tumors (PNETs).

METHODS

The expression of PD-L1 and PD-1 in 80 patients diagnosed with PNETs were investigated. Immunohistochemical analysis was performed on 80 formalin-fixed paraffin-embedded tissue specimens from PNETs and 20 corresponding cancer-adjacent tissue specimens.

RESULTS

Tissues from PNETs had higher levels of PD-L1 (58.8%) and PD-1 (51.3%) compared to the cancer-adjacent tissues (25% and 20%, respectively). Meanwhile, PD-L1 expression was associated with PD-1 expression (P=0.007). PD-L1 expression was significantly associated with histological type (P=0.014) and tumor stage (P=0.014). Univariate analyses showed that the overall survival time of PNETs patients was significantly associated with PD-L1 expression in cancer cells (P=0.003), PD-1 expression in tumor-infiltrating lymphocytes (P=0.001), tumor node metastasis stage (P<0.05), and distant metastasis (P<0.001). Additionally, multivariate analysis revealed that PD-L1 expression, PD1 expression, and distant metastasis of PNETs were independently associated with survival time. Moreover, Kaplan-Meier survival curves analysis revealed that patients with negative PD-L1 and PD-1 expression had better prognoses.

CONCLUSION

Data suggested that PD-L1 and PD-1 can be useful prognostic biomarkers for survival and can pave the way toward new immunotherapy regimens against PNETs through targeting the PD-L1/PD-1 pathway.

What clinicians are asking pathologists when dealing with lung neuroendocrine neoplasms?

Lung neuroendocrine tumors (NET) are currently classified in resection specimens according to four histological categories, namely typical carcinoid (TC), atypical carcinoid (AC), large-cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC). Diagnostic criteria have remained unchanged in the 2015 WHO classification, which has ratified the wide acceptance and popularity of such terminology in the pathologists׳ and clinicians׳ community. A unifying umbrella of NE morphology and differentiation has been recognized in lung NET, which has pushed to enter an unique box of invasive tumors along with diffuse idiopathic pulmonary NE cell hyperplasia (DIPNECH) as a pre-invasive lesion with a potential toward the development of carcinoids. However, uncertainties remain in the terminology of lung NET upon small samples, where Ki-67 antigen could play some role to avoid misdiagnosing carcinoids as high-grade NE tumors. Epidemiologic, clinical and genetic traits support a biological three-tier over a pathology four-tier model, according to which TC are low malignancy tumors, AC intermediate malignancy tumors and LCNEC/SCC high malignancy tumors with no significant differences in survival among them. Inconsistencies in diagnostic reproducibility, troubles in the therapy of AC and LCNEC, and limitations to histology within the same tumor category argue in favor of a global re-thinking of lung NET where a grading system could play a role. This review outlines three main key questions in the field of lung NET: (A) unbiased diagnoses, (B) the role of Ki-67 and tumor grading, and (C) management of predictive markers. Answers are still inconclusive, thus additional research is required to improve our understanding on lung NET.

Outcome and prognostic factors of multimodal therapy for pulmonary large-cell neuroendocrine carcinomas

Background

There is controversy whether patients diagnosed with large-cell neuroendocrine carcinoma (LCNEC) should be treated according to protocols for non-small cell lung cancers (NSCLC) or small cell lung cancers (SCLC), especially with regard to the administration of prophylactic cranial irradiation (PCI). This study was set up to determine the incidence of brain metastases and to investigate the outcome following multimodal treatment in 70 patients with LCNEC.

Methods

Seventy patients with histologically confirmed LCNEC were treated at the University Hospital of Heidelberg between 2001 and 2014. Data were collected retrospectively. Al most all patients received thoracic surgery as initial treatment (94 %). Chemotherapy was administered in 32 patients as part of the initial treatment. Fourteen patients were treated with adjuvant or definitive thoracic radiotherapy according to NSCLC protocols. Cranial radiotherapy due to brain metastases, mostly given as whole brain radiotherapy (WBRT), was received by fourteen patients. Statistical analysis was performed using the long-rank test and the Kaplan–Meier method.

Results

Without PCI, the detected rate for brain metastases was 25 % after a median follow-up time of 23.4 months, which is comparable to NSCLC patients in general. Overall (OS), local (LPFS), brain metastases-free survival (BMFS) and extracranial distant progression-free survival (eDPFS) was 43, 50, 63 and 50 % at 5 years, respectively. Patients with incomplete resection showed a survival benefit from adjuvant radiotherapy. The administration of adjuvant chemotherapy improved the general worse prognosis in higher pathologic stages.

Conclusion

In LCNEC patients, the administration of radiotherapy according to NSCLC guidelines appears reasonable and contributes to acceptable results of multimodal treatment regimes. The low incidence of spontaneous brain metastases questions a possible role of PCI.

High-grade neuroendocrine carcinoma

PURPOSE OF REVIEW

This review presents an update on classification, diagnosis and potentially 'drugable' molecular alterations of small cell carcinoma (SCC) and large cell neuroendocrine carcinoma (LCNEC) of the lung.

RECENT FINDINGS

The main controversies in the classification of lung neuroendocrine tumors are: whether SCC and LCNEC should remain separated or should be unified into a high-grade category; and what the role is of Ki67 as an adjunct to the classical parameters (mitotic rate and necrosis). Regarding the diagnosis of SCC and LCNEC, in difficult cases it requires the combined evaluation of clinical-radiological data, histological and cytological material and selected immunostains. The prognosis of both tumors remains very poor. Despite the promising identification of potential molecular targets on preclinical studies, including antiangiogenetic drugs and tricyclic antidepressants, at the moment no specific molecular-driven therapy is available.

SUMMARY

The field of high-grade neuroendocrine carcinomas remains complex in several respects, and studies on molecular targets are urgently needed.

Clinical characteristics of the mixed form of neuroendocrine tumor in the lung: A retrospective study in 2501 lung cancer cases

BACKGROUND

A neuroendocrine tumor (NET) is a special kind of epithelial tumor with predominant neuroendocrine differentiation, which arises throughout the body, including the lung. A subpopulation of lung cancer patients suffer from the mixed (combined) form of NET with components of non-neuroendocrine carcinoma. However, the clinical characteristics of the mixed form of NET are not well established.

METHODS

We analyzed 2501 consecutive cases of primary lung cancer from 2009 to 2011. The diagnosis, histology, therapy, and outcome were collected.

RESULTS

A total of 22 patients were enrolled. The occurrence rate of lung cancer was 0.9%. Neither gender (1.2% and 0.3% for male and female, respectively, P = 0.35) nor age (0.6% and 1.3% for patients aged ≤60 and >60, respectively, P = 0.13) was associated with the onset of this disease; however it has become more frequent in recent years (0.6% and 1.6% at the time ≤ and >2010 respectively, P = 0.03). This cohort of 22 patients had a median survival of 60.0 months (95% confidence interval: 14.3-105.6 months). Patients with metastatic disease (60 months and not reached [NR], P = 0.18) or a small-cell lung cancer component tended to have a shorter survival (35 months and NR, P = 0.16). Patients who underwent surgery had a significantly longer survival period (NR and 17.0 months, P = 0.001).

CONCLUSIONS

A mixed form of NET in the lung is a rare disease. While stage and histology might influence prognosis, surgery is the critical factor for long-term survival.

Ki-67 antigen in lung neuroendocrine tumors: unraveling a role in clinical practice

Classification of lung neuroendocrine (NE) tumors is a step-wise process with four tumor categories being identified by morphology, namely typical carcinoid (TC), atypical carcinoid, large-cell NE carcinoma, and small-cell lung carcinoma (SCLC). Ki-67 antigen or protein (henceforth simply Ki-67) has been largely studied in these tumors, but the clinical implications are so far not clear. A well-defined role has regarded the diagnostic use in the separation of TC and AC from SCLC in nonsurgical specimens, with monoclonal antibody MIB-1 resulting in the most used reagent after antigen retrieval procedures. Uncertainties, however, have arisen in its assessment, usually expressed as Ki-67 labeling index, because of some variability in obtaining either value of the fraction. A diagnostic role is currently lacking, even though there are significant differences in most cases between TC and AC, less so between large-cell NE carcinoma and SCLC. In addition, the prognostic role of Ki-67 is debated, likely due to methodological and biological reasons. The last challenge would be to identify an effective lung-specific grading system based on Ki-67 labeling index. In this review article, five relevant issues to Ki-67 have been addressed by using a question-answer methodology, with relevant key points discussing major interpretation issues. The conclusion is that Ki-67 is a feasible and potentially meaningful marker in lung NE tumors, but more data are needed to determine its ideal function in this setting of tumors.

Treatment outcomes of patients with different subtypes of large cell carcinoma of the lung

BACKGROUND

Although large cell neuroendocrine carcinoma (LCNEC) and lymphoepithelioma-like carcinoma (LELC) are the variants of large cell carcinoma (LCC) of lung, there are few studies comparing them. The aim of this study was to compare the clinical characteristic and treatment outcomes of LCNEC, LELC, and classic LCC.

METHODS

Patients with LCNEC, LELC, or classic LCC were identified in a prospectively collected database, and their data were analyzed.

RESULTS

A total of 46 patients with classic LCC, 30 with LCNEC, and 18 with LELC, who received surgical resection with curative intent, were identified and included in the analysis. Patients with LELC were younger, and the frequency of nonsmokers was greater than in patients with classic LCC or LCNEC. In patients with LCNEC or LELC, most lesions were located on the left side. There were 5 surgical deaths, and the median follow-up time of the surviving patients was 44.1 months. The 5-year disease free survival among the three subgroups was similar (p = 0.601), but patients with LELC had a significantly better overall survival than the other two subgroups (LELC vs classic LCC, p = 0.009; LELC vs LCNEC, p = 0.002). Multivariate analysis showed tumor location site, tumor stage, and LELC were independent prognostic factors of overall survival.

CONCLUSIONS

The clinical manifestations and treatment outcomes of LCNEC, LELC, and classic LCC are different. LCNEC has a poor survival, and survival is not different than that of classic LCC. LELC is associated with younger age and a higher frequency of nonsmokers, and the treatment outcomes are better than those of other subtypes.

The tail of neuroendocrine tumors from lung to pancreas: Two rare case reports

INTRODUCTION

Primary pancreatic neuroendocrine tumors are a well-established disease entity, however, neuroendocrine metastases to the pancreas from other sites have been scarcely documented. Specifically, pancreatic metastases from a pulmonary carcinoid tumor have only previously been described in a single case report.

PRESENTATION OF CASE

We sought to outline our institutional experience of two patients with pulmonary neuroendocrine tumors that developed metastases to the pancreas, confirmed by gross pathology and immunohistochemistry. In both cases, the pancreatic metastases were surgically resected and their pulmonary origin were discovered post-operatively.

DISCUSSION

Our findings should raise awareness to the possibility of metastatic disease when evaluating a pancreatic mass in a patient with a clinical history of pulmonary carcinoid tumor. Expert opinion on immunohistochemically differentiating a primary pancreatic neuroendocrine malignancy from a metastasis should be employed in these cases.

CONCLUSION

Establishing this diagnosis pre-operatively could affect the decision to proceed with surgical resection, given the morbidity of pancreatectomy and the unknown long-term clinical outcome of patients with pulmonary carcinoid tumors metastatic to the pancreas.

Unraveling tumor grading and genomic landscape in lung neuroendocrine tumors

Currently, grading in lung neuroendocrine tumors (NETs) is inherently defined by the histological classification based on cell features, mitosis count, and necrosis, for which typical carcinoids (TC) are low-grade malignant tumors with long life expectation, atypical carcinoids (AC) intermediate-grade malignant tumors with more aggressive clinical behavior, and large cell NE carcinomas (LCNEC) and small cell lung carcinomas (SCLC) high-grade malignant tumors with dismal prognosis. While Ki-67 antigen labeling index, highlighting the proportion of proliferating tumor cells, has largely been used in digestive NETs for assessing prognosis and assisting therapy decisions, the same marker does not play an established role in the diagnosis, grading, and prognosis of lung NETs. Next generation sequencing techniques (NGS), thanks to their astonishing ability to process in a shorter timeframe up to billions of DNA strands, are radically revolutionizing our approach to diagnosis and therapy of tumors, including lung cancer. When applied to single genes, panels of genes, exome, or the whole genome by using either frozen or paraffin tissues, NGS techniques increase our understanding of cancer, thus realizing the bases of precision medicine. Data are emerging that TC and AC are mainly altered in chromatin remodeling genes, whereas LCNEC and SCLC are also mutated in cell cycle checkpoint and cell differentiation regulators. A common denominator to all lung NETs is a deregulation of cell proliferation, which represents a biological rationale for morphologic (mitoses and necrosis) and molecular (Ki-67 antigen) parameters to successfully serve as predictors of tumor behavior (i.e., identification of pathological entities with clinical correlation). It is envisaged that a novel grading system in lung NETs based on the combined assessment of mitoses, necrosis, and Ki-67 LI may offer a better stratification of prognostic classes, realizing a bridge between molecular alterations, morphological features, and clinical behavior.

Analysis on the characteristics and prognosis of pulmonary neuroendocrine tumors

OBJECTIVE

To retrospectively review the clinical characteristics and analyze the prognostic factors of Chinese patients with pulmonary neuroendocrine tumors.

MATERIALS AND METHODS

The clinical data of 176 patients with pulmonary neuroendocrine tumors in Chinese PLA General Hospital from Mar., 2000 to Oct., 2012 were retrospectively analyzed. The parameters were evaluated by univariate and multivariate analysis, including the gender, age, smoking history, family history, TNM staging, localization (central or peripheral), tumor size, nodal status, histological subtype and treatment (operation or non-operation).

RESULTS

There were 23 patients with typical carcinoids (TC) (13.1%), 41 with atypical carcinoids (AC) (23.3%), 10 with large cell neuroendocrine carcinoma (LCNEC) (5.7%) and 102 with small cell lung cancer (SCLC) (57.9%). The median follow-up time was 64.5 months for AC, 38 months for LCNEC and 27 months for SCLC. The typical carcinoid censored data was 18 (more than 50% of the patients), so the median follow-up time was not obtained, and actuarial 5-year survivals for TC, AC, LCNEC and SCLC were 75.1%, 51.7%, 26.7% and 38.8%, respectively. COX univariate analysis revealed that the age (P=0.001), histological subtype (P=0.005), nodal status (P=0.000), treatment (P=0.000) and TNM staging (P=0.000) were the prognostic factors of the patients with pulmonary neuroendocrine tumors, whereas its multivariate analysis showed that only the age(P=0.001), TNM staging (P=0.002) and treatment (P=0.000) were independent prognostic factors.

CONCLUSIONS

Radical surgery remains the treatment of choice, and is the only curative option. The age, TNM staging and treatment are confirmed to be the independent prognostic factors in multivariable models for pulmonary neuroendocrine tumors.

Diagnosis and treatment of neuroendocrine lung tumors

Pulmonary neuroendocrine tumors (PNT) encompass a broad spectrum of tumors including typical carcinoid (TC) and atypical (AC) tumors, large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC). Although no variety can be considered benign, AC and TC have a much lower metastatic potential, are usually diagnosed in early stages, and most are candidates for surgical treatment. Several chemotherapy (CT) regimens are available in the case of recurrence or in advanced stages, although scientific evidence is insufficient. LCNEC, which is currently classified alongside large-cell carcinomas, have molecular features, biological behavior and CT sensitivity profile closely resembling SCLC. Pathological diagnosis is often difficult, despite the availability of immunohistochemical techniques, and surgical specimens may be necessary. The diagnostic tests used are similar to those used in other lung tumors, with some differences in the optimal tracer in positron emission tomography. The new TNM classification is useful for staging these tumors. Carcinoid syndrome, very rare in PNT, may cause symptoms that are difficult to control and requires special therapy with somatostatin analogs and other drugs. Overall, with the exception of SCLC, new trials are needed to provide a response to the many questions arising with regard to the best treatment in each lineage and each stage.

Stemness and inducing differentiation of small cell lung cancer NCI-H446 cells

Small cell lung cancer (SCLC) accounts for nearly 15% of human lung cancers and is one of the most aggressive solid tumors. The SCLC cells are thought to derive from self-renewing pulmonary neuroendocrine cells by oncogenic transformation. However, whether the SCLC cells possess stemness and plasticity for differentiation as normal stem cells has not been well understood thus far. In this study, we investigated the expressions of multilineage stem cell markers in the cancer cells of SCLC cell line (NCI-H446) and analyzed their clonogenicity, tumorigenicity, and plasticity for inducing differentiation. It has been found that most cancer cells of the cell line expressed multilineage stem cell markers under the routine culture conditions and generated single-cell clones in anchorage-dependent or -independent conditions. These cancer cells could form subcutaneous xenograft tumors and orthotopic lung xenograft tumors in BALB/C-nude mice. Most cells in xenograft tumors expressed stem cell markers and proliferation cell nuclear antigen Ki67, suggesting that these cancer cells remained stemness and highly proliferative ability in vivo. Intriguingly, the cancer cells could be induced to differentiate into neurons, adipocytes, and osteocytes, respectively, in vitro. During the processes of cellular phenotype-conversions, autophagy and apoptosis were two main metabolic events. There is cross-talking between autophagy and apoptosis in the differentiated cancer cells. In addition, the effects of the inhibitor and agonist for Sirtuin1/2 on the inducing osteogenic differentiation indicated that Sirtuin1/2 had an important role in this process. Taken together, these results indicate that most cancer cells of NCI-H446 cell line possess stemness and plasticity for multilineage differentiation. These findings have potentially some translational applications in treatments of SCLC with inducing differentiation therapy.

[Bronchial carcinoid tumor: study of 60 patients]

BACKGROUND AND OBJECTIVE

To describe the casuistry of bronchial carcinoid tumor in the last 20 years in our hospital and determine survival after surgical treatment.

PATIENTS AND METHOD

We retrospectively reviewed the medical records from January 1992 to June 2012 of patients diagnosed with carcinoid tumor by the pulmonary service.

RESULTS

Fifty-two patients (87%) had typical carcinoid and 8 (13%) atypical carcinoid. The mean age at diagnosis was 60 years (SD: 14.4). There was no relationship between consumption of tobacco and carcinoid tumor. Twenty-two per cent were asymptomatic radiographic finding (incidental finding) Three patients showed carcinoid syndrome and one patient had Cushing syndrome. There was a right dominance and the mean lesion size was between 2.1 and 5 cm. Nine per cent had lymph node involvement, predominantly in atypical carcinoid. Overall survival at 3.5 and 10 years was 94%, 86% and 82%. Survival at 5 years was 90% for typical and 86% for atypical and survival at 10 years was 85% for typical and 57% for atypical carcinoids.

CONCLUSION

Carcinoid tumors are malignant tumors by their ability to metastasize. In our study, both histological type and staging were predictors of survival.

Morphologic analysis of pulmonary neuroendocrine tumors

Background

Few studies on how to diagnose pulmonary neuroendocrine tumors through morphometric analysis have been reported. In this study, we measured and analyzed the characteristic parameters of pulmonary neuroendocrine tumors using an image analyzer to aid in diagnosis.

Methods

Sixteen cases of typical carcinoid tumor, 5 cases of atypical carcinoid tumor, 15 cases of small cell carcinoma, and 51 cases of large cell neuroendocrine carcinoma were analyzed. Using an image analyzer, we measured the nuclear area, perimeter, and the major and minor axes.

Results

The mean nuclear area was 0.318±0.101 µm² in typical carcinoid tumors, 0.326±0.119 µm² in atypical carcinoid tumors, 0.314±0.107 µm² in small cell carcinomas, and 0.446±0.145 µm² in large cell neuroendocrine carcinomas. The mean nuclear circumference was 2.268±0.600 µm in typical carcinoid tumors, 2.408±0.680 µm in atypical carcinoid tumors, 2.158±0.438 µm in small cell carcinomas, and 3.247±1.276 µm in large cell neuroendocrine carcinomas. All parameters were useful in distinguishing large cell neuroendocrine carcinoma from other tumors (p=0.001) and in particular, nuclear circumference was the most effective (p=0.001).

Conclusions

Pulmonary neuroendocrine tumors showed nuclear morphology differences by subtype. Therefore, evaluation of quantitative nuclear parameters improves the accuracy and reliability of diagnosis.

Vectors for inhaled gene therapy in lung cancer. Application for nano oncology and safety of bio nanotechnology

Novel aerosol therapeutic modalities have been investigated for lung cancer. Inhaled gene therapy has presented safety and effectiveness previously in cystic fibrosis. However, safety concerns have been raised regarding the safety of non-viral vectors for inhaled gene therapy in lung cancer, and therefore small steps have been made towards this multifunctional treatment modality. During the last decade, numerous new nanocomplexes have been created and investigated as a safe gene delivery nano-vehicle. These formulations are multifunctional; they can be used as either local therapy or carrier for an effective inhaled gene therapy for lung cancer. Herein, we present current and future perspectives of nanocomplexes for inhaled gene therapy treatment in lung cancer.