Molecular Subtypes of Pulmonary Large-cell Neuroendocrine Carcinoma Predict Chemotherapy Treatment Outcome

Diagnostic Value of Insulinoma-Associated Protein 1 (INSM1) and Comparison With Established Neuroendocrine Markers in Pulmonary Cancers

CONTEXT.—

The diagnostic distinction of pulmonary neuroendocrine (NE) tumors from non-small cell lung carcinomas (NSCLCs) is clinically relevant for prognostication and treatment. Diagnosis is based on morphology and immunohistochemical staining.

OBJECTIVE.—

To determine the diagnostic value of insulinoma-associated protein 1 (INSM1), in comparison with established NE markers, in pulmonary tumors.

DESIGN.—

Fifty-four pulmonary NE tumors and 632 NSCLCs were stained for INSM1, CD56, chromogranin A, and synaptophysin. In a subset, gene expression data were available for analysis. Also, 419 metastases to the lungs were stained for INSM1. A literature search identified 39 additional studies with data on NE markers in lung cancers from the last 15 years. Seven of these included data on INSM1.

RESULTS.—

A positive INSM1 staining was seen in 39 of 54 NE tumors (72%) and 6 of 623 NSCLCs (1%). The corresponding numbers were 47 of 54 (87%) and 14 of 626 (2%) for CD56, 30 of 54 (56%) and 6 of 629 (1%) for chromogranin A, and 46 of 54 (85%) and 49 of 630 (8%) for synaptophysin, respectively. Analysis of literature data revealed that CD56 and INSM1 were the best markers for identification of high-grade NE pulmonary tumors when considering both sensitivity and specificity, while synaptophysin also showed good sensitivity. INSM1 gene expression was clearly associated with NE histology.

CONCLUSIONS.—

The solid data of both our and previous studies confirm the diagnostic value of INSM1 as a NE marker in pulmonary pathology. The combination of CD56 with INSM1 and/or synaptophysin should be the first-hand choice to confirm pulmonary high-grade NE tumors. INSM1 gene expression could be used to predict NE tumor histology.

Factors associated with treatment receipt and overall survival for patients with locally advanced large cell neuroendocrine carcinoma of the lung: A National Cancer Database analysis

PURPOSE

Large cell neuroendocrine carcinoma (LCNEC) is a rare pulmonary malignancy with clinicopathologic features of both non-small cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). Given the paucity of available data regarding LCNEC management, we queried the National Cancer Database (NCDB) to describe trends in management, identify predictors of treatment receipt, and compare outcomes in patients receiving chemotherapy (ChT) and chemoradiotherapy (CRT).

METHODS

We identified patients with locally advanced (Stage III) LCNEC of the lung treated with definitive ChT or CRT between the years of 2004-2015. Odds ratios were calculated to determine predictors of CRT receipt. Multivariable cox regression was used to determine predictors of overall survival.

RESULTS

Using the above criteria, 5797 patients were identified, 54 % of whom received CRT (n = 3153) while 46 % (n = 2644) received ChT alone. Most patients had T4 (35 %) and N2 (59 %) disease. Median overall survival was 11.9 months (11.3-12.6) in patients receiving ChT compared to 16.1 months (15.4-16.9) in patients receiving CRT (p < 0.0001). Overall survival at 1, 3, and 5 years was 50 %, 20 %, and 13 % versus 60 %, 27 %, and 18 %, in patients receiving ChT and CRT, respectively. Older patients and those with higher comorbidity scores were less likely to receive CRT; whereas patients with higher education level, treatment receipt at an academic/research program facility, N2 disease, and later treatment year were more likely to receive CRT. On multivariable analysis, older age, greater comorbidity score, presence of N2 disease, and presence of T4 disease were all associated with decreased OS. CRT receipt was an independent predictor of increased overall survival.

CONCLUSIONS

Definitive CRT was an independent predictor of increased overall survival in patients with locally advanced LCNEC of the lung. Findings from our study may help guide potential areas of future investigation to help define an ideal treatment approach for LCNEC.

New molecular classification of large cell neuroendocrine carcinoma and small cell lung carcinoma with potential therapeutic impacts

Large cell neuroendocrine carcinoma (LCNECs) and small cell lung carcinomas (SCLCs) are high-grade neuroendocrine carcinomas of the lung with very aggressive behavior and poor prognosis. Their histological classification as well as their therapeutic management has not changed much in recent years, but genomic and transcriptomic analyses have revealed different molecular subtypes raising hopes for more personalized treatment. Indeed, four subtypes of SCLCs have been recently described, SCLC-A driven by the master gene ASCL1, SCLC-N driven by NEUROD1, SCLC-Y by YAP1 and SCLC-P by POU2F3. Whereas SCLC standard of care is based on concurrent chemoradiation for limited stages and on chemotherapy alone or chemotherapy combined with anti-PD-L1 checkpoint inhibitors for extensive stage SCLC, SCLC-A variants could benefit from DLL3 or BCL2 inhibitors, and SCLC-N variants from Aurora kinase inhibitors combined with chemotherapy, or PI3K/mTOR or HSP90 inhibitors. In addition, a new SCLC variant (SCLC-IM) with high-expression of immune checkpoints has been also reported, which could benefit from immunotherapies. PARP inhibitors also gave promising results in combination with chemotherapy in a subset of SCLCs. Regarding LCNECs, they represent a heterogeneous group of tumors, some of them exhibiting mutations also found in SCLC but with a pattern of expression of NSCLC, while others harbor mutations also found in NSCLC but with a pattern of expression of SCLC, questioning their clinical management as NSCLCs or SCLCs. Overall, we are probably entering a new area, which, if personalized treatments are effective, will also lead to the implementation in practice of molecular testing or biomarkers detection for the selection of patients who can benefit from them.

Beyond Traditional Morphological Characterization of Lung Neuroendocrine Neoplasms: In Silico Study of Next-Generation Sequencing Mutations Analysis across the Four World Health Organization Defined Groups

Simple Summary

Lung neuroendocrine neoplasms (LNENs) classes, as proposed by the World Health Organization 2015, do not provide properly prognostic and therapeutic indications. In fact, high-throughput molecular analysis, based on next-generation sequencing, identified novel molecular subgroups, associated with different genomic signatures, that could pave the way for alternative therapeutic approaches. The present review, coupled with in silico molecular analysis, could show the current genomic alterations state in actual LNENS groups. Interestingly our manuscript suggests that the molecular novelties could improve the LNENs therapeutics efficacy. In more detail, we reported the differences of gene alterations and mutational rate between LNENS, confirming the central pathogenetic role given by a different mutational rate in chromatin remodeling genes and tumor suppressors TP53-RB1. In conclusion, our results underlined that a further molecular layer is needed to improve the efficacy of LNENs medical treatment.

Abstract

Lung neuroendocrine neoplasms (LNENs) represent a rare and heterogeneous population of lung tumors. LNENs incidence rate has increased dramatically over the past 30 years. The current World Health Organization LNENs classification (WHO 2015), distinguished four LNENs prognostic categories, according to their morphology, necrosis amount and mitotic count: typical carcinoid (TC), atypical-carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC) and small cell lung cancer (SCLC). At present, due to their rarity and biological heterogeneity there is still no consensus on the best therapeutic approach. Next-generation-sequencing analysis showed that WHO 2015 LNENs classes, could be characterized also by specific molecular alterations: frequently mutated genes involving chromatin remodeling and generally characterized by low mutational burden (MB) are frequently detected in both TC and AC; otherwise, TP53 and RB1 tumor suppressor genes alterations and high MB are usually detected in LCNEC and SCLC. We provide an overview concerning gene mutations in each WHO 2015 LNENs class in order to report the current LNENs mutational status as potential tool to better understand their clinical outcome and to drive medical treatment.

Pulmonary Large-Cell Neuroendocrine Carcinoma: Therapeutic Challenges and Opportunities

Pulmonary large cell neuroendocrine carcinoma (P-LCNEC) is a rare, poorly differentiated, non-small cell malignancy within the spectrum of neuroendocrine tumors (NETs) of the lung. Despite sharing several similarities with small cell lung cancer (SCLC) in their clinical, immunohistopathological, genomic, and prognostic features, it is a distinct and biologically heterogeneous entity with challenging diagnostic and therapeutic requirements. Given the lack of prospective, randomized data to guide management, it is common practice to pursue thoracic surgery for resectable tumors according to the guidelines for non-small cell lung cancer (NSCLC) and implement systemic chemotherapy as early as at stage I, similar to the treatment of SCLC. However, important issues, such as the optimal timing and combination of therapeutic modalities, the most effective type of chemotherapy for advanced-stage disease, and the benefit from prophylactic cranial irradiation, remain debated. Accumulating evidence from retrospective, molecular profiling studies supports the existence of at least two P-LCNEC subtypes, most notably a SCLC-like and a NSCLC-like phenotype, which presumably underlie the observed differential sensitivity to platinum-based regimens and warrant further validation as predictive biomarkers of efficacy. Furthermore, several potentially actionable, driver molecular alterations have been identified, offering implications for personalized treatment approaches, including targeted therapies and immunotherapy. The current review discusses open questions on the diagnosis and management of P-LCNEC, as well as recent advances in its genomic and transcriptomic characterization that create promising therapeutic opportunities.

An 11-year retrospective study: clinicopathological and survival analysis of gastro-entero-pancreatic neuroendocrine neoplasm

To investigate the clinicopathological characteristics and relevant prognostic factors of gastro-entero-pancreatic neuroendocrine neoplasm (GEP-NEN), to improve our understanding of GEP-NEN.This was a retrospective analysis of 155 patients (average age 53.7 ± 13.6 years) pathologically diagnosed with GEP-NEN. We analyzed the clinicopathological characteristics, treatment, and prognostic factors of GEP-NEN.The most common primary site was the pancreas (41.9%), followed by the rectum, stomach and duodenum. Most cases were nonfunctional GEP-NENs (149/155) with nonspecific symptoms. TNM stage and histological grade were determined by the latest criteria. Surgical resection was the mainstay of treatment in 150 patients, and 22 patients received chemotherapy under different circumstances. A total of 130 patients were followed up for a median of 44 months, and 1-year and 3-year survival rates were 82.3% and 72.3%, respectively. According to univariate and multivariate analysis, incidental diagnosis, maximum tumor diameter, tumor stage, lymph node and distant metastasis, TNM stage, and histological grade were significantly correlated with overall survival, but histological grade was the only factor confirmed as an independent prognostic factor for long-term survival of GEP-NEN.GEP-NEN, with an increasing trend in incidence, occurred most frequently in the pancreas. Nonfunctional tumors with nonspecific symptoms comprised the majority of cases. The main treatment was surgical resection. Histological grade was confirmed as the only independent prognostic factor.

Exploring imaging features of molecular subtypes of large cell neuroendocrine carcinoma (LCNEC)

OBJECTIVES

Radiological characteristics and radiomics signatures can aid in differentiation between small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC). We investigated whether molecular subtypes of large cell neuroendocrine carcinoma (LCNEC), i.e. SCLC-like (with pRb loss) vs. NSCLC-like (with pRb expression), can be distinguished by imaging based on (1) imaging interpretation, (2) semantic features, and/or (3) a radiomics signature, designed to differentiate between SCLC and NSCLC.

MATERIALS AND METHODS

Pulmonary oncologists and chest radiologists assessed chest CT-scans of 44 LCNEC patients for 'small cell-like' or 'non-small cell-like' appearance. The radiologists also scored semantic features of 50 LCNEC scans. Finally, a radiomics signature was trained on a dataset containing 48 SCLC and 76 NSCLC scans and validated on an external set of 58 SCLC and 40 NSCLC scans. This signature was applied on scans of 28 SCLC-like and 8 NSCLC-like LCNEC patients.

RESULTS

Pulmonary oncologists and radiologists were unable to differentiate between molecular subtypes of LCNEC and no significant differences in semantic features were found. The area under the receiver operating characteristics curve of the radiomics signature in the validation set (SCLC vs. NSCLC) was 0.84 (95% confidence interval (CI) 0.77-0.92) and 0.58 (95% CI 0.29-0.86) in the LCNEC dataset (SCLC-like vs. NSCLC-like).

CONCLUSION

LCNEC appears to have radiological characteristics of both SCLC and NSCLC, irrespective of pRb loss, compatible with the SCLC-like subtype. Imaging interpretation, semantic features and our radiomics signature designed to differentiate between SCLC and NSCLC were unable to separate molecular LCNEC subtypes, which underscores that LCNEC is a unique disease.

Randomised phase II trial of CAPTEM or FOLFIRI as SEcond-line therapy in NEuroendocrine CArcinomas and exploratory analysis of predictive role of PET/CT imaging and biological markers (SENECA trial): a study protocol

INTRODUCTION

Patients with metastatic or locally advanced, non-resectable, grade 3 poorly differentiated gastroenteropancreatic (GEP) and lung neuroendocrine carcinomas (NECs) are usually treated with in first-line platinum compounds. There is no standard second-line treatment on progression. Accurate biomarkers are needed to facilitate diagnosis and prognostic assessment of patients with NEC.

METHODS AND ANALYSIS

The SEcond-line therapy in NEuroendocrine CArcinomas (SENECA) study is a randomised, non-comparative, multicentre phase II trial designed to evaluate the efficacy and safety of folinic acid, 5-fluorouracil and irinotecan (FOLFIRI) or capecitabine plus temozolomide (CAPTEM) regimens after failure of first-line chemotherapy in patients with lung NEC and GEP-NEC. Secondary aims are to correlate the serum miRNA profile and primary mutational status of MEN1, DAXX, ATRX and RB-1 with prognosis and outcome and to investigate the prognostic and predictive role of the Ki-67 score and 18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) or ⁶⁸Ga-PET/CT. The main eligibility criteria are age ≥18 years; metastatic or locally advanced, non-resectable, grade 3 lung or GEP-NECs; progression to first-line platinum-based chemotherapy. A Bryant and Day design taking into account treatment activity and toxicity was used to estimate the sample size. All analyses will be performed separately for each treatment group in the intention-to-treat population. A total of 112 patients (56/arm) will be randomly assigned (1:1) to receive FOLFIRI every 14 days or CAPTEM every 28 days until disease progression or unacceptable toxicity or for a maximum of 6 months. Patients undergo testing for specific biomarkers in primary tumour tissue and for miRNA in blood samples. MiRNA profiling will be performed in the first 20 patients who agree to participate in the biological substudy.

ETHICS AND DISSEMINATION

The SENECA trial, supported by Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST), was authorised by the locals Ethics Committee and the Italian Medicines Agency (AIFA). Results will be widely disseminated via peer-reviewed manuscripts, conference presentations and reports to relevant authorities.The study is currently open in Italy.

TRAIL REGISTRATION NUMBER

NCT03387592; Pre-results. EudraCT-2016-000767-17.

PROTOCOL VERSION

Clinical Study Protocol Version 1, 7 November 2016.

Multiple faces of pulmonary large cell neuroendocrine carcinoma: update with a focus on practical approach to diagnosis

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive malignancy that is strongly linked to smoking and notoriously difficult to diagnose and treat. Recent molecular data reveal that it represents a biologically heterogeneous group of tumors, characterized by morphologic and genomic diversity that straddles small cell and non-small cell lung carcinomas (NSCLCs), and in a minority of cases atypical carcinoids. This review provides an update on recent molecular and clinical developments in LCNEC with the main focus on practical approach to pathologic diagnosis using illustrative examples of the main differential diagnostic considerations.

Outcomes of Patients with Clinical Stage I-IIIA Large-Cell Neuroendocrine Lung Cancer Treated with Resection

Large-cell neuroendocrine carcinoma (LCNEC) is a rare malignancy with poor prognosis. The rationale of the study was to determine the survival of LCNEC patients in I–IIIA clinical stages who underwent resection. A total of 53 LCNEC (89%) and combined LCNEC (11%) patients in stages I–IIIA who underwent surgery with radical intent between 2002–2018 were included in the current study. Overall survival (OS) and time to recurrence (TTR) were estimated. Uni- and multivariable analyses were conducted using Cox-regression model. Patients were treated with surgery alone (51%), surgery with radiochemotherapy (4%), with radiotherapy (2%), with adjuvant chemotherapy (41%), or with neoadjuvant chemotherapy (2%). The median (95% Confidence Interval (CI)) OS and TTR was 52 months (20.1–102.1 months) and 20 months (7.0–75.6 months), respectively. Patients treated in clinical stage I showed better OS than patients in stages II–IIIA (p = 0.008). Patients with R0 resection margin (negative margin, no tumor at the margin) and without lymph node metastasis had significantly better TTR. In the multivariate analysis, age was an independent factor influencing OS. Recurrence within 1 year was noted in more than half cases of LCNEC. R0 resection margin and N0 status (no lymph node metastasis) were factors improving TTR. Age >64 years was observed as a main independent factor influencing OS.

Texture analysis of early cerebral tissue damage in magnetic resonance imaging of patients with lung cancer

Primary tumors can secrete many cytokines, inducing tissue damage or microstructural changes in distant organs. The purpose of this study was to investigate changes in texture features in the cerebral tissue of patients with lung cancer without brain metastasis. In this study, 50 patients with lung cancers underwent 3.0-T magnetic resonance imaging (MRI) within 2 weeks of being diagnosed with lung cancer. Texture analysis (TA) was carried out in 8 gray matter areas, including bilateral frontal cortices, parietal cortices, occipital cortices and temporal cortices, as well as 2 areas of bilateral frontoparietal white matter. The same procedure was performed for 57 healthy controls. A total of 32 texture parameters were separately compared between the patients and controls in the different cerebral tissue sites. Texture features among patients based on histological type and clinical stage were also compared. Of the 32 texture parameters, 27 showed significant differences between patients with lung cancer and healthy controls. There were significant differences in cerebral tissue, both gray matter and white matter between patients and controls, especially in several wavelet-based parameters. However, there were no significant differences between tissue at homologous sites in bilateral hemispheres, either in patients or controls. TA detected overt changes in the texture features of cerebral tissue in patients with lung cancer without brain metastasis compared with those of healthy controls. TA may be considered as a novel and adjunctive approach to conventional brain MRI to reveal cerebral tissue changes invisible on MRI alone in patients with lung cancer.

Neuroendocrine tumors of the lung: clinicopathological and molecular features

In 1970, neuroendocrine tumors of the lung were classified into three categories: typical carcinoid (TC), atypical carcinoid (AC), and small cell lung carcinoma (SCLC). The third edition of the World Health Organization (WHO) classification in 1999 defined large cell neuroendocrine carcinoma (LCNEC) as a variant of large cell carcinomas, whereas the fourth edition of the WHO classification redefined LCNEC as a neuroendocrine tumor. Currently, neuroendocrine tumors of the lung are classified into four main categories: TC, AC, LCNEC, and SCLC. Although the treatments for TC, AC, and SCLC have not changed remarkably, the treatment strategy for LCNEC is not yet established because of its reclassification from a variant of "large cell carcinoma" to a new category of "neuroendocrine tumor". In this review article, we discuss the pathological findings, biological behavior, and treatment of neuroendocrine tumors of the lung.

Efficacy of immune check-point inhibitors (ICPi) in large cell neuroendocrine tumors of lung (LCNEC)

OBJECTIVES

Little is known regarding the ICPi efficacy in LCNEC. We explored the efficacy and safety of ICPi in LCNEC and assessed its impact on OS.

MATERIALS AND METHODS

Thirty-seven consecutive patients with advanced LCNEC were selected from the Davidoff Cancer Center database. These were divided into groups A1 (patients treated with ICPi, n-23) and A2 (patients not treated with ICPi, n-14). Additionally, group A1* was introduced (patients treated with ICPi as a monotherapy, n-21). Another cohort of advanced non-LCNEC lung cancer patients treated with nivolumab at five Israeli cancer centers was chosen as a comparator (group B, n-270). ORR, PFS with ICPi in group A1* were assessed (RECIST 1.1), OS with ICPi was compared between groups A1* and B. OS since advanced disease diagnosis (OSDx) was compared between groups A1 and A2.

RESULTS

In group A1*, ORR and median PFS with ICPi were 33 %, and 4.2 months (95 % CI, 2.4-8.1), respectively. With median follow-up since start of ICPi of 6.2 months [IQR 2.2-12.1] and 4.9 months [IQR 2.3-8.9] in groups A1* and B, respectively, 52 % and 64 % of patients died in groups A1* and B, respectively. Median OS with ICPi comprised 11.8 months (95 % CI, 3.7-NR) and 6.9 months (95 % CI, 5.5-8.1) in groups A1* and B, respectively (p-0.23). Median OSDx was 14.5 months (95 % CI, 10.1-38.9) and 10.3 months (95 % CI, 2.6-NR), in groups A1 and A2, respectively (p-0.54).

CONCLUSION

In advanced LCNEC, ICPi outcomes are comparable to the outcomes observed in advanced NSCLC. Future research is needed to clarify the impact of ICPi on OS, and to correlate its benefit with tumor mutational landscape.

Latest advances in management of small cell lung cancer and other neuroendocrine tumors of the lung

Neuroendocrine tumors of the lung are a diverse group of diseases with distinct pathological, molecular, and clinical characteristics. The most recent World Health Organization (WHO) classification identifies two types of high-grade neuroendocrine carcinomas of the lung: small cell lung carcinoma (SCLC), and the less common large cell neuroendocrine carcinoma of the lung (LCNEC). Systemic treatments for these aggressive tumors have largely remained unchanged for years. With the advancement in genomic sequencing and identification of novel targetable pathways over the last decade, a myriad of therapeutic options have emerged, addressing unmet needs for this patient population. In this review, we summarize the latest advances in the management of SCLC and LCNEC, and discuss promising endeavors in development.

A Semiquantitative Scoring System May Allow Biopsy Diagnosis of Pulmonary Large Cell Neuroendocrine Carcinoma

OBJECTIVES

The aim of this study was to devise reproducible biopsy criteria for distinguishing pulmonary large cell neuroendocrine carcinoma (LCNEC) from non-small cell lung carcinoma (NSCLC).

METHODS

Tissue microarrays of LCNEC and NSCLC were generated from resection specimens and used as biopsy surrogates. They were stained for neuroendocrine markers, Ki-67, napsin-A, and p40, and independently analyzed by standardized morphologic criteria by four pathologists. Tumors were scored based on morphology, neuroendocrine marker expression, and Ki-67 proliferative index.

RESULTS

The average total score for LCNEC was significantly higher than for NSCLC (5.65 vs 0.51, P < .0001). Utilizing a cutoff score of 4 or higher showed 100% sensitivity and 99% specificity for LCNEC diagnosis, with an excellent agreement among four pathologists (98%).

CONCLUSIONS

The proposed semiquantitative approach based on a combination of specific morphologic and immunophenotypic features may be a useful tool for biopsy diagnosis of LCNEC.

Large cell neuroendocrine carcinoma with a solitary brain metastasis and low Ki-67: a unique subtype

INTRODUCTION

Stage IV large cell neuroendocrine carcinoma (LCNEC) of the lung generally presents as disseminated and aggressive disease with a Ki-67 proliferation index (PI) 40-80%. LCNEC can be subdivided in two main subtypes: the first harboring TP53/RB1 mutations (small-cell lung carcinoma (SCLC)-like), the second with mutations in TP53 and STK11/KEAP1 (non-small-cell lung carcinoma (NSCLC)-like). Here we evaluated 11 LCNEC patients with only a solitary brain metastasis and evaluate phenotype, genotype and follow-up.

METHODS

Eleven LCNEC patients with solitary brain metastases were analyzed. Clinical characteristics and survival data were retrieved from medical records. Pathological analysis included histomorphological analysis, immunohistochemistry (pRB and Ki-67 PI) and next-generation sequencing (TP53, RB1, STK11, KEAP1 and MEN1).

RESULTS

All patients had N0 or N1 disease. Median overall survival (OS) was 12 months (95% confidence interval (CI) 5.5-18.5 months). Mean Ki-67 PI was 59% (range 15-100%). In 6/11 LCNEC Ki-67 PI was ≤40%. OS was longer for Ki-67 ≤40% compared to >40% (17 months (95% CI 11-23 months) vs 5 months (95% CI 0.7-9 months), P = 0.007). Two patients were still alive at follow-up after 86 and 103 months, both had Ki-67 ≤40%. 8/11 patients could be subclassified, and both SCLC-like (n = 6) and NSCLC-like (n = 2) subtypes were present. No MEN1 mutation was found.

CONCLUSION

Stage IV LCNEC with a solitary brain metastasis and N0/N1 disease show in the majority of cases Ki-67 PI ≤40% and prolonged survival, distinguishing them from general LCNEC. This unique subgroup can be both of the SCLC-like and NSCLC-like subtype.

The Prognostic and Therapeutic Role of Genomic Subtyping by Sequencing Tumor or Cell-Free DNA in Pulmonary Large-Cell Neuroendocrine Carcinoma

PURPOSE

The optimal systemic treatment for pulmonary large-cell neuroendocrine carcinoma (LCNEC) is still under debate. Previous studies showed that LCNEC with different genomic characteristics might respond differently to different chemotherapy regimens. In this study, we sought to investigate genomic subtyping using cell-free DNA (cfDNA) analysis in advanced LCNEC and assess its potential prognostic and predictive value.

EXPERIMENTAL DESIGN

Tumor DNA and cfDNA from 63 patients with LCNEC were analyzed by target-captured sequencing. Survival and response analyses were applied to 54 patients with advanced stage incurable disease who received first-line chemotherapy.

RESULTS

The mutation landscape of frequently mutated cancer genes in LCNEC from cfDNA closely resembled that from tumor DNA, which led to a 90% concordance in genomic subtyping. The 63 patients with LCNEC were classified into small-cell lung cancer (SCLC)-like and non-small cell lung cancer (NSCLC)-like LCNEC based on corresponding genomic features derived from tumor DNA and/or cfDNA. Overall, patients with SCLC-like LCNEC had a shorter overall survival than those with NSCLC-like LCNEC despite higher response rate (RR) to chemotherapy. Furthermore, treatment with etoposide-platinum was associated with superior response and survival in SCLC-like LCNEC compared with pemetrexed-platinum and gemcitabine/taxane-platinum doublets, while treatment with gemcitabine/taxane-platinum led to a shorter survival compared with etoposide-platinum or pemetrexed-platinum in patients with NSCLC-like LCNEC.

CONCLUSIONS

Genomic subtyping has potential in prognostication and therapeutic decision-making for patients with LCNEC and cfDNA analysis may be a reliable alternative for genomic profiling of LCNEC.

Double-edged role of radiotherapy in patients with pulmonary large-cell neuroendocrine carcinoma

Purpose: Pulmonary large-cell neuroendocrine carcinoma (LCNEC) is classified as non-small-cell lung cancer, but has characteristics similar to small-cell lung cancer. This study was performed to evaluate the effect of surgery and radiotherapy on patients with LCNEC. Materials and Methods: We analyzed 1,619 patients with stage I-III LCNEC, identified from the Surveillance, Epidemiology, and End Results database, diagnosed from 2000 to 2013. The Kaplan-Meier analysis and the Cox proportional hazard model were used to study patient prognosis. Results: Overall, 869 (53.7%) stage I LCNEC patients, 203 (12.5%) stage II patients, and 547 (33.8%) stage III patients were included in the analysis. Various surgery types were all associated with higher overall survival (OS) and lung cancer-specific survival (LCSS) than no surgery, with the following HRs: 0.334 (OS) and 0.279 (LCSS) for lobectomy, 0.468 (OS) and 0.416 (LCSS) for partial/wedge/segmental resection, and 0.593 (OS) and 0.522 (LCSS) for pneumonectomy (all p < 0.05). OS and LCSS of stage I and II LCNEC patients were not improved by radiotherapy (stage I: OS p = 0.719, LCSS p = 0.557; stage II: OS p = 0.136, LCSS p = 0.697). However, in stage III patients, radiotherapy significantly improved both OS and LCSS (p < 0.001). Following multivariate analysis, increased age, male patients, radiotherapy and diagnosed at stage II or III were all independent risk factors for LCNEC (all p < 0.05). Conclusion: Lobectomy had the best outcome for OS and LCSS in stage I-II LCNEC. For stage III LCNEC patients, radiotherapy can significantly improve survival time. However, in LCNEC patients undergoing surgery, radiotherapy may reduce survival time.

DLL3 expression in large cell neuroendocrine carcinoma (LCNEC) and association with molecular subtypes and neuroendocrine profile

OBJECTIVES

For stage IV pulmonary large cell neuroendocrine carcinoma (LCNEC), the only therapeutic option is palliative chemotherapy. DLL3 is a new therapeutic target, which seems to be often expressed in SCLC and LCNEC. It has recently been reported that DLL3 mRNA expression is particularly upregulated in the LCNEC subgroup with STK11/KEAP1 and TP53 co-mutations, in contrast to lower expression levels in RB1 and TP53 co-mutated LCNEC. Our aim was to investigate DLL3 protein expression in stage IV LCNEC and correlate data with mutational profiles (i.e.STK11/KEAP1/RB1), immunostaining results (pRb, NE markers) and clinical characteristics.

MATERIALS AND METHODS

Immunohistochemical analysis for DLL3 (SC16.65) and ASCL1 (SC72.201) was performed on 94 and 51 FFPE tissue sections, respectively, of pathologically reviewed stage IV LCNEC. DLL3 and ASCL1 were scored positive if ≥1% of the tumor cells showed cytoplasmic/membranous or dotlike (DLL3) or nuclear (ASCL1) immunostaining. Data were correlated with available sequencing (TP53, RB1, STK11, KEAP1), immunostaining (pRb, NE markers) and clinical data.

RESULTS

DLL3 was expressed in 70/94 (74%) LCNEC, 56 (80%) of which showed cytoplasmic/membranous staining. Median H-score was 55 (interquartile range 0-160). DLL3 staining was not different in pRb immunohistochemistry negative and positive patients (DLL3+ in 53/70 (76%) vs. 14/21 (67%), p = 0.409) or RB1 mutated and wildtype patients (DLL3+ in 27/34 (79%) vs. 23/33 (70%), p = 0.361). Nevertheless, 6/6 (100%) STK11 mutated, 10/11 (91%) KEAP1 mutated and 9/9 (100%) TP53 wildtype tumors were DLL3+ . Furthermore, DLL3 expression was associated with expression of ASCL1 and at least 2 out of 3 neuroendocrine markers.

CONCLUSION

The high percentage (74%) of DLL3 expression in stage IV LCNEC denotes the potential of DLL3 targeted therapy in this patient group.

Neuroendocrine Tumors of the Lung: Updates and Diagnostic Pitfalls

Neuroendocrine tumors of the lung constitute approximately 20% of all primary lung tumors and include typical carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma. Given their morphologic overlap with diverse mimics, neuroendocrine tumors of the lung can be diagnostically challenging. This review discusses the clinical, histologic, immunophenotypic, and molecular features of pulmonary neuroendocrine tumors, along with common diagnostic pitfalls and strategies for avoidance.

Prognostic nomogram predicts overall survival in pulmonary large cell neuroendocrine carcinoma

BACKGROUND

Large cell neuroendocrine carcinoma (LCNEC) is a rare and typically aggressive malignancy with poor prognosis. This study developed a nomogram model to predict the overall survival (OS) of patients with LCNEC.

METHODS

LCNEC patients were identified from the Surveillance, Epidemiology, and End Results database between 2004-2014. Univariate and multivariate Cox regression models were used to determine demographic and clinicopathological features associated with OS. A nomogram model was generated to predict OS and its performance was assessed by Harrell's concordance index (C-index), calibration plots, and subgroup analysis by risk scores.

RESULTS

Of 3048 eligible patients with LCNEC, 2138 were randomly grouped into the training set and 910 into the validation set. Age at diagnosis, gender, tumor stage, N stage, tumor size, and surgery of primary site were independent prognostic factors of OS. C-index values of the nomogram were 0.75 (95% CI, 0.74-0.76) and 0.76 (95% CI, 0.74-0.77) in the training and validation sets, respectively. In both cohorts, the calibration plots showed good concordance between the predicted and observed OS at 3 and 5 years. Kaplan-Meier curves revealed significant differences in OS in patients stratified by nomogram-based risk score, and patients with a higher-than-median risk score had poorer OS.

CONCLUSION

This is the first nomogram developed and validated in a large population-based cohort for predicting OS in patients with LCNEC, and it shows favorable discrimination and calibration abilities. Use of this proposed nomogram has the potential to improve prediction of survival risk, and lead to individualized clinical decisions for LCNEC.

Large-Cell Neuroendocrine Carcinoma of the Lung: A Population-Based Study

INTRODUCTION

Large-cell neuroendocrine carcinoma (LCNEC) accounts for approximately 3% of lung malignancies. There are limited data on the epidemiology and best treatment practices for this malignancy. This study aimed to be the largest cohort with the most up-to-date analysis of the epidemiology of LCNEC.

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried to identify cases of LCNEC diagnosed from 2010 through 2015, reflecting years the American Joint Committee on Cancer 7th edition staging system was in use. Using these data, we compared the epidemiology, demographics, clinical characteristics, and survival times of LCNEC with small-cell lung carcinoma (SCLC) and non-SCLC (NSCLC). Trends in incidence and mortality were recorded from 2004 to 2015.

RESULTS

A total of 195,148 cases of lung cancer, including 1681 (0.9%) cases of LCNEC, were analyzed. LCNEC was more common among male subjects, and disease usually presented at stage IV (55%). Brain metastasis occurred more frequently in LCNEC (19.2%) than SCLC (16.7%, P < .001) or NSCLC (13%, P < .001). Incidence increased by 0.011 people per 100,000 per year, primarily of stage IV disease. Annual mortality from LCNEC doubled over the time period studied. Survival in patients with stage I-III LCNEC mirrored survival trends of patients with NSCLC, whereas stage IV LCNEC behaved similarly to SCLC.

CONCLUSION

LCNEC generally presents at more advanced stages than NSCLC but earlier than SCLC. Stage I-III LCNEC behaves similarly to NSCLC, whereas stage IV is more akin to SCLC. LCNEC incidence is increasing. Despite this, it remains poorly studied and did not demonstrate an improved prognosis in our cohort.

The Antiviral Agent Cidofovir Induces DNA Damage and Mitotic Catastrophe in HPV-Positive and -Negative Head and Neck Squamous Cell Carcinomas In Vitro

Cidofovir (CDV) is an antiviral agent with antiproliferative properties. The aim of our study was to investigate the efficacy of CDV in HPV-positive and -negative head and neck squamous cell carcinoma (HNSCC) cell lines and whether it is caused by a difference in response to DNA damage. Upon CDV treatment of HNSCC and normal oral keratinocyte cell lines, we carried out MTT analysis (cell viability), flow cytometry (cell cycle analysis), (immuno) fluorescence and western blotting (DNA double strand breaks, DNA damage response, apoptosis and mitotic catastrophe). The growth of the cell lines was inhibited by CDV treatment and resulted in γ-H2AX accumulation and upregulation of DNA repair proteins. CDV did not activate apoptosis but induced S- and G2/M phase arrest. Phospho-Aurora Kinase immunostaining showed a decrease in the amount of mitoses but an increase in aberrant mitoses suggesting mitotic catastrophe. In conclusion, CDV inhibits cell growth in HPV-positive and -negative HNSCC cell lines and was more profound in the HPV-positive cell lines. CDV treated cells show accumulation of DNA DSBs and DNA damage response activation, but apoptosis does not seem to occur. Rather our data indicate the occurrence of mitotic catastrophe.

Methylation Density Pattern of KEAP1 Gene in Lung Cancer Cell Lines Detected by Quantitative Methylation Specific PCR and Pyrosequencing

Background. The KEAP1/NRF2 pathway is the key regulator of antioxidants and cellular stress responses, and is implicated in neoplastic progression and resistance of tumors to treatment. KEAP1 silencing by promoter methylation is widely reported in solid tumors as part of the complex regulation of the KEAP1/NRF2 axis, but its prognostic role remains to be addressed in lung cancer. Methods. We performed a detailed methylation density map of 13 CpGs located into the KEAP1 promoter region by analyzing a set of 25 cell lines from different histologies of lung cancer. The methylation status was assessed using quantitative methylation specific PCR (QMSP) and pyrosequencing, and the performance of the two assays was compared. Results. Hypermethylation at the promoter region of the KEAP1 was detected in one third of cell lines and its effect on the modulation KEAP1 mRNA levels was also confirmed by in vitro 5-Azacytidine treatment on lung carcinoid, small lung cancer and adenocarcinoma cell lines. QMSP and pyrosequencing showed a high rate of concordant results, even if pyrosequencing revealed two different promoter CpGs sub-islands (P1a and P1b) with a different methylation density pattern. Conclusions. Our results confirm the effect of methylation on KEAP1 transcription control across multiple histologies of lung cancer and suggest pyrosequencing as the best approach to investigate the pattern of CpGs methylation in the promoter region of KEAP1. The validation of this approach on lung cancer patient cohorts is mandatory to clarify the prognostic value of the epigenetic deregulation of KEAP1 in lung tumors.

Comparison of four DLL3 antibodies performance in high grade neuroendocrine lung tumor samples and cell cultures

Background

Small cell lung cancer (SCLC) is usually diagnosed in the advanced stage. It has a very poor prognosis, with no advancements in therapy in the last few decades. A recent phase 1 clinical study, using an antibody-drug conjugate directed against DLL3, showed promising results. A prerequisite for this therapy is an immunohistochemical test for DLL3 expression. The antibody used in the clinical trial was bound to a specific platform, which is not available in all pathology laboratories. In this study, the expression of DLL3 was analyzed using different DLL3 antibodies in high-grade neuroendocrine tumors of the lung and cell cultures. Additionally, correlation of DLL3 expression with Rb1 loss and TP53 mutation was evaluated.

Methods

The study cohort consisted of surgically resected cases, 24 SCLC and 29 large cell neuroendocrine carcinoma (LCNEC), from which tissue microarrays (TMAs) were constructed. The validation cohort included 46 SCLC samples, mostly small biopsies. Additionally, well-characterized SCLC cell lines were used. Immunohistochemical analysis was performed using four different DLL3 antibodies, as well as TP53 and Rb1 antibodies. Expression was evaluated microscopically and manually scored.

Results

The comparison of all DLL3 antibodies showed poor results for the overall agreement, as well as positive and negative agreement. Differences were observed regardless of the applied cut-off values and the tumor type. The antibody used in the clinical trial was the only which always positively stained the tumor cells obtained from cell cultures with known DLL3 expression and was negative on cells that did not express DLL3. There was no correlation between p53 and DLL3 expression in SCLC and LCNEC. RB1 loss in SCLC showed statistical significant correlation with the DLL3 positivity (p = 0.037), while no correlation was found in LCNEC.

Conclusion

The DLL3 antibody used in the clinical trial demonstrated superiority in the detection of DLL3 expression. Cell cultures, which can be used for DLL3 antibodies as positive and negative probes, were established. Evidence of DLL3 expression in high proportions of patients with LCNEC might provide basis for studies of new therapy options in this group of patients.

Lung and digestive neuroendocrine neoplasms. From WHO classification to biomarker screening: Which perspectives?

The recent classifications of lung and digestive neuroendocrine neoplasms (NENs) make a fundamental distinction between well- and poorly-differentiated neoplasms. Well-differentiated NENs are termed carcinoids in the lung and neuroendocrine tumors in the gastroenteropancreatic sphere; their risk of malignancy is highly variable; histological grading is used to stratify patients into prognostically significant groups. Poorly-differentiated NENs are termed neuroendocrine carcinoma in both the lung and the digestive sphere; they constantly are of high grade of malignancy; two types are recognized on the basis of tumor cell morphology, the small cell and the large cell types. Recent studies have largely uncovered the genetic landscape of several subsets of well-differentiated NENs (lung, pancreas, small intestine) and of poorly-differentiated NENs. Some molecular markers may help to the differential diagnosis between highly proliferative neuroendocrine tumors and neuroendocrine carcinomas, especially in the pancreas. In well-differentiated tumors, MGMT status is proposed as a predictive marker of the response to temozolomide, but remains to be validated. In poorly-differentiated neoplasms, large cell neuroendocrine carcinoma has been shown to be a heterogeneous category, with some cases presenting the same molecular signature than small cell carcinoma and others the same signature than adenocarcinomas of the same body site. Rb protein has been recently shown to be a potential marker of response to platinum salts in neuroendocrine carcinoma. Much remains to be done to translate the rapid progress in the molecular understanding of NENS into diagnostic, prognostic or predictive markers.

Characteristics of 252 patients with bronchopulmonary neuroendocrine tumours treated at the Copenhagen NET Centre of Excellence

BACKGROUND

Bronchopulmonary neuroendocrine tumours are divided into typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell lung cancer (SCLC).

AIM

To thoroughly describe a cohort of 252 patients with TC, AC and LCNEC (SCLC excluded).

MATERIAL AND METHODS

Collection of data from 252 patients referred to and treated at Rigshospitalet 2008-2016. Data was collected from electronic patient files and our prospective NET database. Statistics were performed in SPSS.

RESULTS

162 (64%) had TC, 29 (12%) had AC and 61 (24%) had LCNEC. Median age at diagnosis was 69 years (range: 19-89) with no difference between genders. Thoraco-abdominal CT was performed in all patients at diagnosis. FDG-PET/CT was performed in 207 (82%) at diagnosis and was positive in 95% of the entire cohort, with no difference between tumour types. Synaptophysin was positive in 98%, chromogranin A in 92% and CD56 in 97%. Mean Ki67 index was 5% in TC, 16% in AC and 69% in LCNEC (p < 0.001). Metastatic disease was found in 4% of TC, 27% of AC and 58% of LCNEC at time of initial diagnosis (p < 0.001). In total 179 patients (71%) underwent surgical resection; TC: 87%, AC: 72% and LCNEC: 28% (p < 0.001). Of the resected patients, 11 (6%) had recurrence. Five-year survival rate was 88% for TC, 63% for AC and 20% for LCNEC.

CONCLUSION

In this comprehensive study of a cohort of 252 patients, one of the largest until date, with TC, AC and LCNEC, the gender distribution showed female predominance with 68%. FDG-PET/CT was positive in 95% of the patients independent of tumour type, which confirms that FDG-PET/CT should be a part of the preoperative work-up for TC, AC and LCNEC. Tumour type was the single most potent independent prognostic factor.

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.

Comparison of genomic landscapes of large cell neuroendocrine carcinoma, small cell lung carcinoma, and large cell carcinoma

Background

The classification of large cell neuroendocrine carcinoma (LCNEC) has generated considerable debate and has been revised since its recognition as a separate entity. Although it shares clinical features with small cell lung carcinoma (SCLC) and was classified with SCLC in the 2015 World Health Organization classification system, numerous studies have revealed inferior treatment outcomes of LCNEC when it was treated as SCLC. Because the incidence of LCNEC is rare, its mutational landscape has not been comprehensively interrogated.

Methods

We performed capture‐based ultra‐deep targeted sequencing on tumor samples of LCNEC, large cell carcinoma (LCC), and SCLC to elucidate its biological relationship with these subtypes and to identify potentially targetable molecular alterations.

Results

Our data revealed a molecular signature, consisting of RUNX1, ERBB4, BRCA1, and EPHA3, that is distinctively mutated in LCNEC. A majority (60%) of LCNEC patients harbored copy number variations (CNVs). Interestingly, there were no common CNVs shared among the three subtypes: NFкBIA amplification was shared between LCNEC and LCC, while AKT2 amplification was shared between LCNEC and SCLC. Furthermore, genetic alterations in the PI3K/AKT/mTOR pathway were enriched in all three subtypes.

Conclusion

Despite the histological and/or morphological similarities among LCNEC, LCC, and SCLC, our data revealed a molecular signature, consisting of RUNX1, ERBB4, BRCA1, and EPHA3, that is distinctively mutated in LCNEC, which has the potential to be used as a panel of biomarkers to distinguish LCNEC from a molecular perspective. Furthermore, the molecular distinction among the three subtypes can also be reflected from CNV events.

Prevalence and prognostic value of PD-L1 expression in molecular subtypes of metastatic large cell neuroendocrine carcinoma (LCNEC)

BACKGROUND

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare tumor with high mutational burden. Two subtypes of LCNEC are recognized, the co-mutated TP53 and RB1 group and the TP53 and STK11/KEAP1 group. We investigated PD-L1 and CD8 expression in a well characterized stage IV LCNEC cohort and compared expression in the two subtypes.

METHODS

Immunohistochemical (IHC) analysis for PD-L1 and CD8 was performed on pathological reviewed pretreatment tumor samples for 148 stage IV LCNEC. Data about targeted next generation sequencing (TNGS) (TP53, RB1, STK11, KEAP1) and IHC for RB1 were available for most tumors. IHC staining for PD-L1 (DAKO 28-8) was performed and scored positive if tumors showed ≥1% membranous staining. CD8 was scored for intra-tumor T-cells and stromal cells.

RESULTS

PD-L1 IHC expression data could be generated in 98/148 confirmed LCNEC samples along with RB1 IHC (n = 97) of which 77 passed quality control for TNGS. PD-L1 expression was positive in 16/98 cases (16%); 5 (5%) with ≥50%. PD-L1 expression was equal in RB1 mutated and RB1 wildtype tumors. None of STK11 mutated tumors (n = 7) expressed PD-L1. PD-L1 expression was correlated with superior overall survival (OS), hazard ratio 0.55 ((95% Confidence Interval 0.31-0.96), p = 0.038). Intra-tumor CD8 was associated with PD-L1 expression (p = 0.021) and stromal and intra-tumor CD8 were correlated with improved OS (p = 0.037 and p = 0.026 respectively).

CONCLUSIONS

PD-L1 expression was positive in 16% of stage IV LCNEC tumors. This was independent of molecular subtype but associated with CD8 expression. In LCNEC patients with PD-L1 and/or CD8 expression superior OS was observed.

Is the sum of positive neuroendocrine immunohistochemical stains useful for diagnosis of large cell neuroendocrine carcinoma (LCNEC) on biopsy specimens?

Aims

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is underdiagnosed on biopsy specimens. We evaluated if routine neuroendocrine immunohistochemical (IHC) stains are helpful in the diagnosis of LCNEC on biopsy specimens.

Methods and results

Using the Dutch pathology registry (PALGA), surgically resected LCNEC with matching pre‐operative biopsy specimens were identified and haematoxylin and IHC slides (CD56, chromogranin‐A, synaptophysin) requested. Subsequently, three pathologists assigned (1) the presence or absence of the WHO 2015 criteria and (2) cumulative size of all (biopsy) specimens. For validation, a tissue microarray (TMA) of non‐small‐cell lung cancer (NSCLC) (n = 77) and LCNEC (n = 19) was used. LCNEC was confirmed on the resection specimens in 32 of 48 re‐reviewed cases. In 47% (n = 15 of 32) LCNEC was also confirmed in the paired biopsy specimens. Neuroendocrine morphology was absent in 53% (n = 17 of 32) of paired biopsy specimens, more often when smaller amounts of tissue were available for evaluation [29% < 5 mm (n = 14) versus 67% ≥5 mm (n = 18) P = 0.04]. Combined with current WHO criteria, positive staining for greater than or equal to two of three neuroendocrine IHC markers increased the sensitivity for LCNEC from 47% to 93% on paired biopsy specimens, and further validated using an independent TMA of LCNEC and NSCLC with sensitivity and specificity of 80% and 99%, respectively.

Conclusions

LCNEC is difficult to diagnose because neuroendocrine morphology is frequently absent in biopsy specimens. In NSCLC devoid of obvious morphological squamous or adenocarcinoma features, positive staining in greater than or equal to two of three neuroendocrine IHC stains supports the diagnosis of LCNEC.

ALK-rearrangement neuroendocrine carcinoma of the lung: a comprehensive study of a rare case series and review of literature

Driver mutations involving tyrosine kinase receptors play crucial roles in the oncogenesis of lung adenocarcinoma. However, receptor tyrosine kinase mutations are extremely rare events in primary pulmonary neuroendocrine carcinoma (NEC), which is a molecular heterogeneous entity. In this study, we examined 4 cases of NEC with anaplastic lymphoma kinase (ALK) rearrangement between 2008 and 2018 at our hospital. We comprehensively analyzed the carcinomas’ clinicopathological features, genetic alterations, and response to ALK inhibitor. One case of atypical carcinoid tumor and 1 case of large cell NEC (LCNEC) achieved response to ALK inhibitor (crizotinib) treatment. One case of combined LCNEC with adenocarcinoma harboring KLC1-ALK (K9:A20) fusion genes was confirmed by NGS of both components, while only the LCNEC component presented RB1 mutation. Notably, tumor cells of different components exhibited different ALK-positive signal patterns by fluorescence in situ hybridization, which revealed isolated 3′ signals in the adenocarcinoma component but split signals in the LCNEC. As the largest case series study, our findings suggested that preliminary screening for ALK rearrangement should also be considered in atypical carcinoid and high-grade NEC. Patients with ALK rearrangement-positive NEC would benefit from ALK inhibitor intervention.

Lung Cancers: Molecular Characterization, Clonal Heterogeneity and Evolution, and Cancer Stem Cells

Lung cancer causes the largest number of cancer-related deaths in the world. Most (85%) of lung cancers are classified as non-small-cell lung cancer (NSCLC) and small-cell lung cancer (15%) (SCLC). The 5-year survival rate for NSCLC patients remains very low (about 16% at 5 years). The two predominant NSCLC histological phenotypes are adenocarcinoma (ADC) and squamous cell carcinoma (LSQCC). ADCs display several recurrent genetic alterations, including: KRAS, BRAF and EGFR mutations; recurrent mutations and amplifications of several oncogenes, including ERBB2, MET, FGFR1 and FGFR2; fusion oncogenes involving ALK, ROS1, Neuregulin1 (NRG1) and RET. In LSQCC recurrent mutations of TP53, FGFR1, FGFR2, FGFR3, DDR2 and genes of the PI3K pathway have been detected, quantitative gene abnormalities of PTEN and CDKN2A. Developments in the characterization of lung cancer molecular abnormalities provided a strong rationale for new therapeutic options and for understanding the mechanisms of drug resistance. However, the complexity of lung cancer genomes is particularly high, as shown by deep-sequencing studies supporting the heterogeneity of lung tumors at cellular level, with sub-clones exhibiting different combinations of mutations. Molecular studies performed on lung tumors during treatment have shown the phenomenon of clonal evolution, thus supporting the occurrence of a temporal tumor heterogeneity.

Immunohistochemical Biomarkers of Gastrointestinal, Pancreatic, Pulmonary, and Thymic Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are a heterogeneous group of epithelial neoplastic proliferations that irrespective of their primary site share features of neural and endocrine differentiation including the presence of secretory granules, synaptic-like vesicles, and the ability to produce amine and/or peptide hormones. NENs encompass a wide spectrum of neoplasms ranging from well-differentiated indolent tumors to highly aggressive poorly differentiated neuroendocrine carcinomas. Most cases arise in the digestive system and in thoracic organs, i.e., the lung and thymus. A correct diagnostic approach is crucial for the management of patients with both digestive and thoracic NENs, because their high clinical and biological heterogeneity is related to their prognosis and response to therapy. In this context, immunohistochemistry represents an indispensable diagnostic tool that pathologists need to use for the correct diagnosis and classification of such neoplasms. In addition, immunohistochemistry is also useful in identifying prognostic and theranostic markers. In the present article, the authors will review the role of immunohistochemistry in the routine workup of digestive and thoracic NENs.

New Insights into the Molecular Characteristics of Pulmonary Carcinoids and Large Cell Neuroendocrine Carcinomas, and the Impact on Their Clinical Management

Carcinoids and large cell neuroendocrine carcinomas (LCNECs) are rare neuroendocrine lung tumors. Here we provide an overview of the most updated data on the molecular characteristics of these diseases. Recent genomic studies showed that carcinoids generally contain a low mutational burden and few recurrently mutated genes. Most of the reported mutations occur in chromatin-remodeling genes (e.g., menin 1 gene [MEN1]), and few affect genes of the phosphoinositide 3-kinase (PI3K)-AKT-mechanistic target of rapamycin gene pathway. Aggressive disease has been related to chromothripsis, DNA-repair gene mutations, loss of orthopedia homeobox/CD44, and upregulation of ret proto-oncogene gene (RET) gene expression. In the case of LCNECs, which present with a high mutation burden, two major molecular subtypes have been identified: one with biallelic inactivation of tumor protein p53 gene (TP53) and retinoblastoma gene (RB1), a hallmark of SCLC; and the other one with biallelic inactivation of TP53 and serine/threonine kinase 11 gene (STK11)/kelch like ECH associated protein 1 gene (KEAP1), genes that are frequently mutated in NSCLC. These data, together with the identification of common mutations in the different components of combined LCNEC tumors, provide further evidence of the close molecular relation of LCNEC with other lung tumor types. In terms of therapeutic options, future studies should explore the association between mechanistic target of rapamycin pathway mutations and response to mechanistic target of rapamycin inhibitors in carcinoids. For LCNEC, preliminary data suggest that the two molecular subtypes might have a predictive value for chemotherapy response, but this observation needs to be validated in randomized prospective clinical trials. Finally, delta like Notch canonical ligand 3 inhibitors and immunotherapy may provide alternative options for patient-tailored therapy in LCNEC.

Treatment outcomes and incidence of brain metastases in pulmonary large cell neuroendocrine carcinoma

INTRODUCTION

Large cell neuroendocrine carcinoma (LCNEC) is a rare type of high-grade pulmonary neuroendocrine tumor. The study objective is to investigate its survival outcomes, incidence of brain metastases, and patterns of recurrence.

METHODS

This is a single center study of patients with pathologic diagnosis of pulmonary LCNEC. Patient data were collected retrospectively and analyzed, including survival, incidence of brain metastases, and patterns of recurrence.

RESULTS

Of 87 patients (stages I: 24, II: 14, III: 23, IV: 26), 52 were managed curatively and 35 palliatively. The median follow-up time was 17.3 months (range 0.6-89.5) for those treated with curative intent and 7.0 months (range 0.1-28.6) for those treated palliatively. The 2- and 5-year overall survival (OS) rates are 48.4% and 25.5% for the curative group, with a median OS of 13.5 months. In the palliative group, the OS are 30.8% at 1 year and 6.8% at 2 years, with a median OS of 7.0 months. Thirty-eight of 52 (73%) patients treated with curative intent had disease relapse, with the common sites being regional lymph nodes (20), brain (18), bones (11), and liver (9). The incidence of brain recurrence among those managed curatively are 21.4% and 41.3%, respectively at 1 and 2 years. Of 18 patients experiencing brain metastases, 14 developed them as part of a first relapse.

CONCLUSIONS

LCNEC's survival outcomes are poor. The incidence of brain metastases is higher than what is observed for other types of nonsmall cell lung cancers. Prophylactic cranial irradiation should be investigated as a means of improving outcomes.