Two prognostically significant subtypes of high-grade lung neuroendocrine tumours independent of small-cell and large-cell neuroendocrine carcinomas identified by gene expression profiles

Cellular and molecular biology of small cell lung cancer: an overview

Although the incidence of small cell lung cancer (SCLC) has declined during the past 30 years, it remains a frustrating disease to research and treat. Numerous attempts to enhance the anti-tumor effects of traditional chemotherapy for SCLC have not been successful. For any tumor to become cancerous, various genetic mutations and biologic alterations must occur in the cell that, when combined, render it a malignant neoplasm. New and novel therapies based on understanding these mechanisms of transformation are needed. Herein we provide an in-depth view of some of the genomic alterations in SCLC that have emerged as potential targets for therapeutic intervention.

Next-Generation Sequencing of Pulmonary Large Cell Neuroendocrine Carcinoma Reveals Small Cell Carcinoma-like and Non-Small Cell Carcinoma-like Subsets

PURPOSE

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a highly aggressive neoplasm, whose biologic relationship to small cell lung carcinoma (SCLC) versus non-SCLC (NSCLC) remains unclear, contributing to uncertainty regarding optimal clinical management. To clarify these relationships, we analyzed genomic alterations in LCNEC compared with other major lung carcinoma types.

EXPERIMENTAL DESIGN

LCNEC (n = 45) tumor/normal pairs underwent targeted next-generation sequencing of 241 cancer genes by Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) platform and comprehensive histologic, immunohistochemical, and clinical analysis. Genomic data were compared with MSK-IMPACT analysis of other lung carcinoma histologies (n = 242).

RESULTS

Commonly altered genes in LCNEC included TP53 (78%), RB1 (38%), STK11 (33%), KEAP1 (31%), and KRAS (22%). Genomic profiles segregated LCNEC into 2 major and 1 minor subsets: SCLC-like (n = 18), characterized by TP53+RB1 co-mutation/loss and other SCLC-type alterations, including MYCL amplification; NSCLC-like (n = 25), characterized by the lack of coaltered TP53+RB1 and nearly universal occurrence of NSCLC-type mutations (STK11, KRAS, and KEAP1); and carcinoid-like (n = 2), characterized by MEN1 mutations and low mutation burden. SCLC-like and NSCLC-like subsets revealed several clinicopathologic differences, including higher proliferative activity in SCLC-like tumors (P < 0.0001) and exclusive adenocarcinoma-type differentiation marker expression in NSCLC-like tumors (P = 0.005). While exhibiting predominant similarity with lung adenocarcinoma, NSCLC-like LCNEC harbored several distinctive genomic alterations, including more frequent mutations in NOTCH family genes (28%), implicated as key regulators of neuroendocrine differentiation.

CONCLUSIONS

LCNEC is a biologically heterogeneous group of tumors, comprising distinct subsets with genomic signatures of SCLC, NSCLC (predominantly adenocarcinoma), and rarely, highly proliferative carcinoids. Recognition of these subsets may inform the classification and management of LCNEC patients. Clin Cancer Res; 22(14); 3618-29. ©2016 AACR.

Prognostic significance of CpG island methylator phenotype in surgically resected small cell lung carcinoma

Methylation is closely involved in the development of various carcinomas. However, few datasets are available for small cell lung cancer (SCLC) due to the scarcity of fresh tumor samples. The aim of the present study is to clarify relationships between clinicopathological features and results of the comprehensive genome‐wide methylation profile of SCLC. We investigated the genome‐wide DNA methylation status of 28 tumor and 13 normal lung tissues, and gene expression profiling of 25 SCLC tissues. Following unsupervised hierarchical clustering and non‐negative matrix factorization, gene ontology analysis was performed. Clustering of SCLC led to the important identification of a CpG island methylator phenotype (CIMP) of the tumor, with a significantly poorer prognosis (P = 0.002). Multivariate analyses revealed that postoperative chemotherapy and non‐CIMP were significantly good prognostic factors. Ontology analyses suggested that the extrinsic apoptosis pathway was suppressed, including TNFRSF1A, TNFRSF10A and TRADD in CIMP tumors. Here we revealed that CIMP was an important prognostic factor for resected SCLC. Delineation of this phenotype may also be useful for the development of novel apoptosis‐related chemotherapeutic agents for treatment of the aggressive tumor.

The comparative pathology of genetically engineered mouse models for neuroendocrine carcinomas of the lung

INTRODUCTION

Because small-cell lung carcinomas (SCLC) are seldom resected, human materials for study are limited. Thus, genetically engineered mouse models (GEMMs) for SCLC and other high-grade lung neuroendocrine (NE) carcinomas are crucial for translational research.

METHODS

The pathologies of five GEMMs were studied in detail and consensus diagnoses reached by four lung cancer pathology experts. Hematoxylin and Eosin and immunostained slides of over 100 mice were obtained from the originating and other laboratories and digitalized. The GEMMs included the original Rb/p53 double knockout (Berns Laboratory) and triple knockouts from the Sage, MacPherson, and Jacks laboratories (double knockout model plus loss of p130 [Sage laboratory] or loss of Pten [MacPherson and Jacks laboratories]). In addition, a GEMM with constitutive co-expression of SV40 large T antigen and Ascl1 under the Scgb1a1 promoter from the Linnoila laboratory were included.

RESULTS

The lung tumors in all of the models had common as well as distinct pathological features. All three conditional knockout models resulted in multiple pulmonary tumors arising mainly from the central compartment (large bronchi) with foci of in situ carcinoma and NE cell hyperplasia. They consisted of inter- and intra-tumor mixtures of SCLC and large-cell NE cell carcinoma in varying proportions. Occasional adeno- or large-cell carcinomas were also seen. Extensive vascular and lymphatic invasion and metastases to the mediastinum and liver were noted, mainly of SCLC histology. In the Rb/p53/Pten triple knockout model from the MacPherson and Jacks laboratories and in the constitutive SV40/T antigen model many peripherally arising non-small-cell lung carcinoma tumors having varying degrees of NE marker expression were present (non-small-cell lung carcinoma-NE tumors). The resultant histological phenotypes were influenced by the introduction of specific genetic alterations, by inactivation of one or both alleles of specific genes, by time from Cre activation and by targeting of lung cells or NE cell subpopulations.

CONCLUSION

The five GEMM models studied are representative for the entire spectrum of human high-grade NE carcinomas and are also useful for the study of multistage pathogenesis and the metastatic properties of these tumors. They represent one of the most advanced forms of currently available GEMM models for the study of human cancer.

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.

Cytohistology of papillary carcinoid and emerging concept of pulmonary neuroendocrine neoplasms

This timely review starts by reporting the clinical, cytologic and histologic features of a morphologic variant of pulmonary carcinoid tumor forming exclusively of papillae. This growth pattern is so rare that it was not included in 2014 WHO classification of pulmonary neuroendocrine neoplasms. The current concept is reviewed, and example of spindle cell carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma, and small cell carcinoma are illustrated with fine needle aspiration cytology, surgical and clinical follow-up. Finally, the new findings in cell biology and molecular biology that led to the emerging concept that carcinoids and high-grade neuroendocrine lung carcinomas are separate biological entities are reviewed and summarized in a tumorigenic module.

[Molecular pathology of lung cancer. State of the art 2014]

Lung cancer is the most frequent cause of cancer-related death in Germany in men and women alike. While in the last decades a classification of epithelial lung tumors into non-small cell and small cell lung cancer was clearly sufficient from the therapeutic viewpoint, the dawn of the era of personalized medicine together with tremendous developments in the field of high throughput technologies have led to a molecular individualization of these tumors and, even more important, to a molecularly defined individualization of tumor therapy. This development resulted in the definition of a wide array of molecularly divergent tumor families. In this article we will give an overview on relevant molecular alterations in non-small cell lung cancers, comprising adenocarcinomas, squamous cell carcinomas and large cell carcinomas and also small cell carcinomas and carcinoids. Besides some similarities data gathered in the last few years specifically highlighted the immense diversity of molecular alterations that might underlie tumorigenesis of lung neoplasms. The knowledge on how to detect these alterations is of utmost importance in pathology, as treatment decisions are increasingly based on their presence or absence, putting molecular pathology in the central focus of the novel era of personalized medicine in oncology.

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.

Identifying CDKN3 Gene Expression as a Prognostic Biomarker in Lung Adenocarcinoma via Meta-analysis

Lung cancer is among the major causes of cancer deaths, and the survival rate of lung cancer patients is extremely low. Recent studies have demonstrated that the gene CDKN3 is related to neoplasia, but in the literature severe controversy exists over whether it is involved in cancer progression or, conversely, tumor inhibition. In this study, we investigated the expression of CDKN3 and its association with prognosis in lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) using datasets in Lung Cancer Explorer (LCE; http://qbrc.swmed.edu/lce/). We found that CDKN3 was up-regulated in ADC and SCC compared to normal tissues. We also found that CDKN3 was expressed at a higher level in SCC than in ADC, which was further validated through meta-analysis (coefficient = 2.09, 95% CI = 1.50-2.67, P < 0.0001). In addition, based on meta-analysis for the prognostic value of CDKN3, we found that higher CDKN3 expression was associated with poorer survival outcomes in ADC (HR = 1.65, 95% CI = 1.39-1.96, P < 0.0001), but not in SCC (HR = 1.10, 95% CI = 0.84-1.44, P = 0.494). Our findings indicate that CDKN3 may be a prognostic marker in ADC, though the detailed mechanism is yet to be revealed.

Expression profiling of receptor tyrosine kinases in high-grade neuroendocrine carcinoma of the lung: a comparative analysis with adenocarcinoma and squamous cell carcinoma

Background

As the comprehensive genomic analysis of small cell lung cancer (SCLC) progresses, novel treatments for this disease need to be explored. With attention to the direct connection between the receptor tyrosine kinases (RTKs) of tumor cells and the pharmacological effects of specific inhibitors, we systematically assessed the RTK expressions of high-grade neuroendocrine carcinomas of the lung [HGNECs, including SCLC and large cell neuroendocrine carcinoma (LCNEC)].

Patients and methods

Fifty-one LCNEC and 61 SCLC patients who underwent surgical resection were enrolled in this research. As a control group, 202 patients with adenocarcinomas (ADCs) and 122 patients with squamous cell carcinomas (SQCCs) were also analyzed. All the tumors were stained with antibodies for 10 RTKs: c-Kit, EGFR, IGF1R, KDR, ERBB2, FGFR1, c-Met, ALK, RET, and ROS1.

Results

The LCNEC and SCLC patients exhibited similar clinicopathological characteristics. The IHC scores for each RTK were almost equivalent between the LCNEC and SCLC groups, but they were significantly different from those of the ADC or SQCC groups. In particular, c-Kit was the only RTK that was remarkably expressed in both LCNECs and SCLCs. On the other hand, about 20 % of the HGNEC tumors exhibited strongly positive RTK expression, and this rate was similar to those for the ADC and SQCC tumors. Intriguingly, strongly positive RTKs were almost mutually exclusive in individual tumors.

Conclusions

Compared with ADC or SQCC, LCNEC and SCLC had similar expression profiles for the major RTKs. The exclusive c-Kit positivity observed among HGNECs suggests that c-Kit might be a distinctive RTK in HGNEC.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-015-1989-z) contains supplementary material, which is available to authorized users.

Statistical completion of a partially identified graph with applications for the estimation of gene regulatory networks

We study the estimation of a Gaussian graphical model whose dependent structures are partially identified. In a Gaussian graphical model, an off-diagonal zero entry in the concentration matrix (the inverse covariance matrix) implies the conditional independence of two corresponding variables, given all other variables. A number of methods have been proposed to estimate a sparse large-scale Gaussian graphical model or, equivalently, a sparse large-scale concentration matrix. In practice, the graph structure to be estimated is often partially identified by other sources or a pre-screening. In this paper, we propose a simple modification of existing methods to take into account this information in the estimation. We show that the partially identified dependent structure reduces the error in estimating the dependent structure. We apply the proposed method to estimating the gene regulatory network from lung cancer data, where protein-protein interactions are partially identified from the human protein reference database. The application shows that proposed method identified many important cancer genes as hub genes in the constructed lung cancer network. In addition, we validated the prognostic importance of a newly identified cancer gene, PTPN13, in four independent lung cancer datasets. The results indicate that the proposed method could facilitate studying underlying lung cancer mechanisms and identifying reliable biomarkers for lung cancer prognosis.

Small cell lung cancer: where do we go from here?

Small cell lung cancer (SCLC) is an aggressive disease that accounts for approximately 14% of all lung cancers. In the United States, approximately 31,000 patients are diagnosed annually with SCLC. Despite numerous clinical trials, including at least 40 phase 3 trials since the 1970s, systemic treatment for patients with SCLC has not changed significantly in the past several decades. Consequently, the 5-year survival rate remains low at <7% overall, and most patients survive for only 1 year or less after diagnosis. Unlike nonsmall cell lung cancer (NSCLC), in which major advances have been made using targeted therapies, there are still no approved targeted drugs for SCLC. Significant barriers to progress in SCLC include 1) a lack of early detection modalities, 2) limited tumor tissue for translational research (eg, molecular profiling of DNA, RNA, and/or protein alterations) because of small diagnostic biopsies and the rare use of surgical resection in standard treatment, and 3) rapid disease progression with poor understanding of the mechanisms contributing to therapeutic resistance. In this report, the authors review the current state of SCLC treatment, recent advances in current understanding of the underlying disease biology, and opportunities to advance translational research and therapeutic approaches for patients with SCLC.

Recent advances in histogenesis research of lung neuroendocrine cancers: Evidence obtained from functional analyses of primitive neural/neuroendocrine cell-specific transcription factors

Small cell carcinoma (SmCC) and large cell neuroendocrine carcinoma (LENEC) are categorized as neuroendocrine cancers (NECs) of the lung and have extremely poor prognoses. The lack of an effective therapeutic strategy against SmCC and LCNEC is a serious issue. Because the regulation of the cellular phenotype is complicated by the actions of various transcription factors, investigations into the function of neural/neuroendocrine cell-specific transcription factors are important for elucidating the cellular characteristics and histogenesis of SmCC and LCNEC and for establishing innovative therapeutic strategies against them. In this review, the functions of ASCL1, NeuroD1, REST, TTF1, and class III/IV POU, that are specifically and highly expressed in lung NECs, are introduced. These transcription factors transactivate and/or transrepress various genes and are involved in neural progenitor phenotyping, neuroendocrine and stem cell marker expression, and epithelial-to-mesenchymal transition. Based on the evidence that certain carcinoids express ASCL1, NeuroD1, TTF1, and class III/IV POU and that lung NECs can develop from non-NE cells/non-NEC cells, the relationships among lung NECs, carcinoid tumors, and non-NECs are discussed. Finally, a model of the histogenesis of lung NECs in view of similarities in the expression of primitive neural/neuroendocrine cell-specific transcription factors is proposed.

Lung neuroendocrine tumors: correlation of ubiquitinylation and sumoylation with nucleo-cytosolic partitioning of PTEN

Background

The tumor suppressor phosphatase and tensin homolog (PTEN) is a pleiotropic enzyme, inhibiting phosphatidyl-inositol-3 kinase (PI3K) signaling in the cytosol and stabilizing the genome in the nucleus. Nucleo-cytosolic partitioning is dependent on the post-translational modifications ubiquitinylation and sumoylation. This cellular compartmentalization of PTEN was investigated in lung neuroendocrine tumors (lung NET).

Methods

Tumor tissues from 192 lung NET patients (surgical specimens = 183, autopsies = 9) were investigated on tissue microarrays. PTEN was H-scored by two investigators in nucleus and cytosol using the monoclonal antibody 6H2.1. Results were correlated with immunoreactivity for USP7 (herpes virus-associated ubiquitin-specific protease 7) and SUMO2/3 (small ubiquitin-related modifier protein 2/3) as well as PTEN and p53 FISH gene status. Clinico-pathologic data including overall survival, proliferation rate and diagnostic markers (synaptophysin, chromogranin A, Mib-1, TTF-1) were recorded.

Results

The multicentre cohort included 58 typical carcinoids (TC), 42 atypical carcinoids (AC), 32 large cell neuroendocrine carcinomas (LCNEC) and 60 small cell lung carcinomas (SCLC). Carcinoids were smaller in size and had higher synaptophysin and chromogranin A, but lower TTF-1 expressions. Patients with carcinoids were predominantly female and 10 years younger than patients with LCNEC/SCLC. In comparison to the carcinoids, LCNEC/SCLC tumors presented a stronger loss of nuclear and cytosolic PTEN associated with a loss of PTEN and p53. Concomitantly, a loss of nuclear USP7 but increase of nuclear and cytosolic SUMO2/3 was found. Loss of nuclear and cytosolic PTEN, loss of nuclear USP7 and increase of cytosolic SUMO2/3 thus correlated with poor survival. Among carcinoids, loss of cytosolic PTEN was predominantly found in TTF1-negative larger tumors of male patients. Among SCLC, loss of both cytosolic and nuclear PTEN but not proliferation rate or tumor size delineated a subgroup with poorer survival (all p-values <0.05).

Conclusions

Cellular ubiquitinylation and sumoylation likely influence the functional PTEN loss in high grade lung NET. Both nuclear and cytosolic PTEN immunoreactivity should be considered for correlation with clinico-pathologic parameters.

Beyond adenocarcinoma: current treatments and future directions for squamous, small cell, and rare lung cancer histologies

Lung cancer encompasses a diverse spectrum of histologic subtypes. Until recently, the majority of therapeutic advances were limited to the minority of patients with adenocarcinoma. With the advent of comprehensive genomic profiling of squamous and small cell lung cancers, new therapeutic targets have emerged. For squamous tumors, the most promising of these include fibroblast growth factor receptor (FGFR), the phosphatidylinositol 3-kinase (PI3K) pathway, discoidin domain receptor 2 (DDR2), and G1/S checkpoint regulators. In 2014, the antiangiogenic agent ramucirumab was approved for all non-small cell lung cancer (NSCLC) histologies, including squamous tumors. Immunotherapeutic approaches also appear to be promising for these cases. Genomic analysis of small cell lung cancer has revealed a high mutation burden, but relatively few druggable driver oncogenic alterations. Current treatment strategies under investigation are focusing on targeting mitotic, cell cycle, and DNA repair regulation, as well as immunotherapy. Pulmonary neuroendocrine tumors represent a diverse spectrum of diseases that may be treated with somatostatin analogs, cytotoxic agents, and molecularly targeted therapies. Radiolabeled somatostatin analogs and combinations with mammalian target of rapamycin (mTOR) inhibitors also show potential. Large cell neuroendocrine tumors share numerous clinical, pathologic, and molecular features with small cell lung cancer; however, whether they should be treated similarly or according to a NSCLC paradigm remains a matter of debate.

ASCL1 is a lineage oncogene providing therapeutic targets for high-grade neuroendocrine lung cancers

Aggressive neuroendocrine lung cancers, including small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), represent an understudied tumor subset that accounts for approximately 40,000 new lung cancer cases per year in the United States. No targeted therapy exists for these tumors. We determined that achaete-scute homolog 1 (ASCL1), a transcription factor required for proper development of pulmonary neuroendocrine cells, is essential for the survival of a majority of lung cancers (both SCLC and NSCLC) with neuroendocrine features. By combining whole-genome microarray expression analysis performed on lung cancer cell lines with ChIP-Seq data designed to identify conserved transcriptional targets of ASCL1, we discovered an ASCL1 target 72-gene expression signature that (i) identifies neuroendocrine differentiation in NSCLC cell lines, (ii) is predictive of poor prognosis in resected NSCLC specimens from three datasets, and (iii) represents novel "druggable" targets. Among these druggable targets is B-cell CLL/lymphoma 2, which when pharmacologically inhibited stops ASCL1-dependent tumor growth in vitro and in vivo and represents a proof-of-principle ASCL1 downstream target gene. Analysis of downstream targets of ASCL1 represents an important advance in the development of targeted therapy for the neuroendocrine class of lung cancers, providing a significant step forward in the understanding and therapeutic targeting of the molecular vulnerabilities of neuroendocrine lung cancer.

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.

Treatment options for patients with large cell neuroendocrine carcinoma of the lung

Large cell neuroendocrine carcinoma (LCNEC) of the lung is categorized as a variant of large cell carcinomas, and LCNEC tumors display biological behaviors resembling those of small cell lung carcinomas and features of high-grade neuroendocrine tumors. Because patients with LCNEC have a poor prognosis, surgery alone is not sufficient. Multimodality therapies, including adjuvant chemotherapy, appear promising for improved prognosis in patients with LCNEC. In this review article, we discuss treatment options for patients with LCNEC of the lung.

Brief report on the use of radiolabeled somatostatin analogs for the diagnosis and treatment of metastatic small-cell lung cancer patients

INTRODUCTION

The demonstration of type 2 somatostatin receptors (SSTRs) in small-cell lung cancer (SCLC) represents the rationale for the use of positron emission tomography/computed tomography (PET/CT) to determine SSTR expression, and select patients suitable for peptide radioreceptor radionuclide therapy (PRRT) in extensive-disease stage (ED) SCLC.

METHODS

We evaluated 24 ED-SCLC patients with radiolabeled SST-analog PET/CT. Lesions at PET/CT scan were semiquantitatively scored (from 0 to 3+) and compared with contrast-enhanced CT findings. Patients scored as 3+ were admitted to PRRT after dosimetric evaluation. Average injected activity/cycle was 2.6 GBq (yttrium-PRRT) or 6.0 GBq (lutetium-PRRT). PRRT efficacy was clinically and radiologically assessed.

RESULTS

PET/CT was negative in four of 24 patients, whereas in the remaining 20 cases uptake was scored as 1+ in seven of 20, 2+ in one of 20, and 3+ in 12 of 20. Primary tumor lesions showed uptake in 16 of 24 patients. Uptake in metastatic lesions was observed in four of four adrenals, two of five brain, 12 of 16 bone, three of eight liver, and 17 of 20 lymph node lesions. Of the 12 patients eligible for PRRT, 11 were eventually treated and four of 11 patients received multiple PRRT administrations. Dosimetry resulted in a BED for kidney of 7.5 Gy (range, 4-21); bone marrow provisional dosage was 0.43 Gy (range, 0.1-1.7). Hematological PRRT toxicity occurred in three of 11 patients. No clinical or objective responses were observed with disease progression occurring approximately 48 days (range, 9-32) after PRRT.

CONCLUSION

Radiolabeled SST-analog PET/CT demonstrated enhanced SSTR expression in 50% of cases. Nevertheless, PRRT in ED-SCLC was ineffective, suggesting the need to anticipate or combine PRRT in a multimodality approach.

A subset of small cell lung cancer with low neuroendocrine expression and good prognosis: a comparison study of surgical and inoperable cases with biopsy

Patients with small cell lung carcinoma (SCLC) rarely demonstrate long-term survival. We previously reported that gene expression profiling identified a subset of SCLC with good prognosis in surgical cases. To find an easier way to routinely identify SCLC belonging to this subset, we conducted the present study with a hypothesis that neuroendocrine (NE) or basaloid (BA) phenotypes may influence prognosis. To confirm the subset, we used an array platform to analyze fresh samples. Because inoperable cases may differ from surgical cases, we enrolled 51 biopsy cases and 43 resected samples. To evaluate NE and BA phenotypes, we used NE (synaptophysin, chromogranin A, and CD56) and BA (p63 and CK34βE12) markers. To varying extents, expression profiling based on the array platform duplicated the subsets. For NE phenotypes, 77% of surgical cases and 100% of biopsy cases were positive for at least 1 marker. For BA phenotypes, only 19% of surgical cases were positive for at least 1 marker, whereas there were no positive biopsy cases. Cases undergoing surgery were categorized based on NE and BA immunoreactivity; 58% into NE+BA-, 19% into NE+BA+, 23% into NE-BA-, and 0 into NE-BA+ groups. NE- patients (n = 10) demonstrated a significantly better prognosis (P = .0306) than their NE+ counterparts (n = 33), whereas no survival difference was evident between the BA+ and BA- groups. Multivariate analyses showed that NE positivity was an independent prognostic factor. In conclusion, the SCLC subset with good prognosis is identified by low NE marker expression, which was found only in surgical cases.

Co-expression network analysis identifies Spleen Tyrosine Kinase (SYK) as a candidate oncogenic driver in a subset of small-cell lung cancer

Background

Oncogenic mechanisms in small-cell lung cancer remain poorly understood leaving this tumor with the worst prognosis among all lung cancers. Unlike other cancer types, sequencing genomic approaches have been of limited success in small-cell lung cancer, i.e., no mutated oncogenes with potential driver characteristics have emerged, as it is the case for activating mutations of epidermal growth factor receptor in non-small-cell lung cancer. Differential gene expression analysis has also produced SCLC signatures with limited application, since they are generally not robust across datasets. Nonetheless, additional genomic approaches are warranted, due to the increasing availability of suitable small-cell lung cancer datasets. Gene co-expression network approaches are a recent and promising avenue, since they have been successful in identifying gene modules that drive phenotypic traits in several biological systems, including other cancer types.

Results

We derived an SCLC-specific classifier from weighted gene co-expression network analysis (WGCNA) of a lung cancer dataset. The classifier, termed SCLC-specific hub network (SSHN), robustly separates SCLC from other lung cancer types across multiple datasets and multiple platforms, including RNA-seq and shotgun proteomics. The classifier was also conserved in SCLC cell lines. SSHN is enriched for co-expressed signaling network hubs strongly associated with the SCLC phenotype. Twenty of these hubs are actionable kinases with oncogenic potential, among which spleen tyrosine kinase (SYK) exhibits one of the highest overall statistical associations to SCLC. In patient tissue microarrays and cell lines, SCLC can be separated into SYK-positive and -negative. SYK siRNA decreases proliferation rate and increases cell death of SYK-positive SCLC cell lines, suggesting a role for SYK as an oncogenic driver in a subset of SCLC.

Conclusions

SCLC treatment has thus far been limited to chemotherapy and radiation. Our WGCNA analysis identifies SYK both as a candidate biomarker to stratify SCLC patients and as a potential therapeutic target. In summary, WGCNA represents an alternative strategy to large scale sequencing for the identification of potential oncogenic drivers, based on a systems view of signaling networks. This strategy is especially useful in cancer types where no actionable mutations have emerged.

Pulmonary neuroendocrine tumors: study of 90 cases focusing on clinicopathological characteristics, immunophenotype, preoperative biopsy, and frozen section diagnoses

BACKGROUND AND OBJECTIVES

Pulmonary neuroendocrine tumors have a prognostic spectrum including typical carcinoid (TC), atypical carcinoid (AC), small cell carcinoma (SCLC), and large cell neuroendocrine carcinoma (LCNEC). We conducted a retrospective study to compare their clinicopathological characteristics, immunophenotype, preoperative biopsy and frozen section diagnoses, and prognosis.

METHODS

Ninety cases of surgically treated pulmonary neuroendocrine tumors were studied. Immunohistochemical studies were performed using antibodies to chromogranin A, synaptophysin, and CD56. The preoperative biopsy and frozen section diagnoses were reviewed.

RESULTS

The 5-year survival rates for TC, AC, SCLC, and LCNEC were 96.6%, 66.7%, 42.4%, and 38.0%, respectively. T stage and pleural status correlated with outcome of SCLC and LCNEC, but N-stage and overall TNM stage did not. In preoperative biopsy, accurate diagnosis was achieved in 5 of 11 TC, 2 of 4 AC, 6 of 15 SCLC, and 0 of 5 LCNEC cases. Using frozen sections, accurate diagnosis was achieved in 8 of 12 TC, 2 of 11 SCLC, and 0 of 11 LCNEC cases.

CONCLUSIONS

LCNEC was the most difficult to diagnose using either preoperative biopsy or frozen sections. T stage and pleural status can predict outcome of SCLC and LCNEC.

BAI3, CDX2 and VIL1: a panel of three antibodies to distinguish small cell from large cell neuroendocrine lung carcinomas

AIMS

Discriminating small-cell lung carcinoma (SCLC) from large-cell neuroendocrine carcinoma (LCNEC) rests on morphological criteria, and reproducibility has been shown to be poor. We aimed to identify immunohistochemical markers to assist this diagnosis.

METHODS AND RESULTS

Gene expression profiling on laser captured frozen tumour samples from eight SCLC and eight LCNEC tumours identified a total of 888 differentially expressed genes (DEGs), 23 of which were validated by qRT-PCR. Antibodies to four selected gene products were then evaluated as immunohistochemical markers on a cohort of 173 formalin-fixed paraffin-embedded (FFPE) SCLC/LCNEC tumour samples, including 26 indeterminate tumours without a consensus diagnosis. Three markers, CDX2, VIL1 and BAI3, gave significantly different results in the two tumour types (P < 0.0001): CDX2 and VIL1 in combination (either marker positive) showed sensitivity and specificity of 81% for LCNEC while BAI3 showed 89% sensitivity and 75% specificity for SCLC. Of the 26 indeterminate tumours 15 (58%) showed an immunophenotype suggesting either SCLC or LCNEC, eight (31%) showed staining of both tumour types, and three (11%) were negative for all markers.

CONCLUSION

A panel of three markers, BAI3, CDX2 and VIL1, is a useful adjunct in the diagnosis of these tumour types.

Genomic deregulation of the E2F/Rb pathway leads to activation of the oncogene EZH2 in small cell lung cancer

Small cell lung cancer (SCLC) is a highly aggressive lung neoplasm with extremely poor clinical outcomes and no approved targeted treatments. To elucidate the mechanisms responsible for driving the SCLC phenotype in hopes of revealing novel therapeutic targets, we studied copy number and methylation profiles of SCLC. We found disruption of the E2F/Rb pathway was a prominent feature deregulated in 96% of the SCLC samples investigated and was strongly associated with increased expression of EZH2, an oncogene and core member of the polycomb repressive complex 2 (PRC2). Through its catalytic role in the PRC2 complex, EZH2 normally functions to epigenetically silence genes during development, however, it aberrantly silences genes in human cancers. We provide evidence to support that EZH2 is functionally active in SCLC tumours, exerts pro-tumourigenic functions in vitro, and is associated with aberrant methylation profiles of PRC2 target genes indicative of a “stem-cell like” hypermethylator profile in SCLC tumours. Furthermore, lentiviral-mediated knockdown of EZH2 demonstrated a significant reduction in the growth of SCLC cell lines, suggesting EZH2 has a key role in driving SCLC biology. In conclusion, our data confirm the role of EZH2 as a critical oncogene in SCLC, and lend support to the prioritization of EZH2 as a potential therapeutic target in clinical disease.

An exploration of pathways involved in lung carcinoid progression using gene expression profiling

Pulmonary carcinoids comprise a well-differentiated subset of neuroendocrine tumors usually associated with a favorable prognosis, but mechanisms underlying disease progression are poorly understood. In an explorative approach to identify pathways associated with progression, we compared gene expression profiles of tumors from five patients with a favorable and five with a poor disease outcome. Differentially expressed genes were validated using quantitative real-time PCR on 65 carcinoid tumors, in combination with survival analysis. One of the identified pathways was further examined using immunohistochemistry. As compared with other chromosomal locations, a significantly higher number of genes downregulated in carcinoids with a poor prognosis were located at chromosome 11q (P = 0.00017), a region known to be frequently lost in carcinoids. In addition, a number of upregulated genes were found involved in the mitotic spindle checkpoint, the chromosomal passenger complex (CPC), mitotic kinase CDC2 activity and the BRCA-Fanconi anemia pathway. At the individual gene level, BIRC5 (survivin), BUB1, CD44, IL20RA, KLK12 and OTP were independent predictors of patient outcome. For survivin, the number of positive nuclei was also related to poor prognosis within the group of carcinoids. Aurora B kinase and survivin, major components of the CPC, were particularly upregulated in high-grade carcinomas and may therefore comprise therapeutic targets for these tumors. To our knowledge, this is the first expression profiling study focusing specifically on pulmonary carcinoids and progression. We have identified novel pathways underlying malignant progression and validated several genes as being strong prognostic indicators, some of which could serve as putative therapeutic targets.

Neuroendocrine tumours--challenges in the diagnosis and classification of pulmonary neuroendocrine tumours

Pulmonary neuroendocrine (NE) proliferations are a diverse group of disorders which share distinct cytological, architectural and biosynthetic features. Tumours composed of NE cells are dispersed among different tumour categories in the WHO classification of tumours and as such do not conform to a singular group with regards to treatment and prognosis. This is reflected by the highly variable behaviour of NE proliferations, ranging from asymptomatic, for instance in diffuse idiopathic pulmonary NE cell hyperplasia and tumourlets, to highly malignant cancers such as small cell lung cancer and large cell NE carcinoma. In this review NE proliferations are described as distinct entities ranging from low grade lesions to high grade cancers. The differential diagnoses are considered with each of the entries. Finally, mention is made of tumours which may show some NE features.

Multiple reaction monitoring of multiple low-abundance transcription factors in whole lung cancer cell lysates

Lung cancer-related transcription factors (TFs) were identified by integrating previously reported genomic, transcriptomic, and proteomic data and were quantified by multiple reaction monitoring (MRM) in various cell lines. All experiments were performed without affinity depletion or subfractionation of cell lysates. Since the target proteins were expected to be present in low abundance, we experimentally optimized MRM transition parameters with chemically synthesized peptides. Quantitation was based on stable isotope-labeled standard peptides (SIS peptides). Out of 288 MRM measurements (36 peptides representing 28 TFs × 8 cell lines), 241 were successfully obtained within a quantitation limit of 15 amol, 221 measurements (91.7%) showed coefficients of variation (CVs) of ≤ 20%, and 149 (61.8%) showed CVs of ≤ 10%, quantifying as low as 19.4 amol/μg protein for STAT2 with a CV of 6.3% in an A549 cell. Comparisons between MRM measurements and levels of the corresponding mRNAs revealed linear, nonlinear, or no relationship between protein and mRNA levels, indicating the need for an MRM assay. An integrative analysis of MRM and gene expression profiles from doxorubicin-resistant H69AR and sensitive H69 cells further showed that 14 differentially expressed TFs, such as STAT1 and SMAD4, regulated genes associated with drug resistance and cell differentiation-related processes. Thus, the analytical performance of MRM for the quantitation of low abundance TFs suggests its usefulness for biological application.

Combined large cell neuroendocrine carcinoma and adenocarcinoma with epidermal growth factor receptor mutation in a female patient who never smoked

A female patient in her sixties, who had never smoked, was found to have a 5-mm nodule in a computed tomography (CT) scan. The follow-up CT scan after 19 months showed that the nodule had grown to 26 mm. We performed a left upper lobectomy. Pathological examination revealed a combined large cell neuroendocrine carcinoma (LCNEC) and adenocarcinoma with components of large cell carcinoma and bronchioloalveolar carcinoma (BAC). Tumor cells were separately collected from components of both the LCNEC and adenocarcinoma, and a mutational analysis of the epidermal growth factor receptor (EGFR) gene demonstrated that both components had the same L861Q mutation at exon 21. We assume that the LCNEC originated from the adenocarcinoma based on the fact that the patient was a non-smoking female, the tumor was located in the periphery, the tumor had a BAC component, and the same EGFR mutation was found in both the LCNEC and adenocarcinoma components.

Clinicopathological features and the impact of the new TNM classification of malignant tumors in patients with pulmonary large cell neuroendocrine carcinoma

The prognosis of patients with large-cell neuroendocrine carcinoma (LCNEC) of the lung is extremely poor and the optimal treatment for these patients has yet to be determined. In this study, we described the clinicopathological characteristics of LCNECs and compared the prognoses of corresponding stages determined by the guidelines of the 6th and 7th editions of the TNM classification of malignant tumors. Clinical data from 42 patients diagnosed with primary LCNEC who underwent treatment at Kitasato University Hospital between 1991 and 2009 were retrospectively analyzed. On follow-up of 42 patients, 22 (52.4%) had confirmed recurrent tumors, including 8 patients with mediastinal lymph node recurrences and 19 with distant metastases. The sites of distant metastases included the brain in 8, bone in 8, liver in 7, lungs in 5 and adrenal glands in 4 patients. For all the patients, the 5-year overall survival rate was 34.7% and the 5-year disease-free survival rate was 32.9%. The 5-year overall survival rates of patients with stage I cancers according to the 6th and 7th staging editions was 51.3% (6th n=18, 7th n=16). Thirteen of 42 patients (31.0%) also had metachronous or synchronous primary cancers. Patients with LCNEC had poor outcomes, even those with stage I tumors classified according to the 7th edition of the TNM classification. Therefore, frequent recurrences in addition to metachronous or synchronous primary cancers in patients with LCNEC should be treated.

Multicentre phase II study of cisplatin-etoposide chemotherapy for advanced large-cell neuroendocrine lung carcinoma: the GFPC 0302 study

BACKGROUND

The optimal treatment of large-cell neuroendocrine carcinoma (LCNEC) of the lung remains unclear. Here, our primary objective was to assess the efficacy of cisplatin-etoposide doublet chemotherapy in advanced LCNEC. Accuracy of the pathological diagnosis and treatment toxicity were assessed as secondary objectives.

PATIENTS AND METHODS

Prospective, multicentre, single-arm, phase II study with a centralised review of treatment-response and pathological data. Patients had untreated performance status (PS) 0/1 stage IV/IIIB LCNEC and received cisplatin (80 mg/m22 d1) and etoposide (100 mg/m22 d1-3) every 21 days.

RESULTS

Eighteen centres included 42 patients (mean age, 59 ± 9 years; 69% men; median of four cycles/patient). At least one grade-3/4 toxicity occurred in 59% of patients (neutropaenia, thrombocytopaenia, and anaemia in 32%, 17%, and 12%, respectively). The median progression-free survival (PFS) and overall survival (OS) were 5.2 months (95% confidence interval, CI, 3.1-6.6) and 7.7 months (95% CI, 6.0-9.6), respectively. The centralised pathologist review reclassified 11 of 40 (27.5%) patients: 9 as small-cell lung cancer, 1 as undifferentiated non-small-cell lung cancer, and 1 as atypical carcinoid. Survival data were not significantly changed by excluding the reclassified patients.

CONCLUSIONS

The pathological diagnosis of LCNEC is difficult. The outcomes of advanced LCNEC treated with cisplatin-etoposide doublets are poor, similar to those of patients with advanced small-cell lung carcinoma (SCLC).

Classification of lung cancer: proposals for change?

Clinical need and developments in pathology and molecular biology require our cancer classifications to be constantly updated to keep them relevant and useful. A review of lung cancer classification is due and has been initiated with new proposals on classification of lung adenocarcinoma. Other major lung cancer types also deserve a similar consideration. As well as addressing the categories of tumor, as signed out in surgical resection specimens, recent proposals on small diagnostic-sample reporting would be an important addition to any new classification. The huge increase in data on the molecular biology of lung cancer has improved our understanding of these diseases, has driven improved therapy for some patients, and must be reflected in the way lung cancer is classified.

Variant Ciz1 is a circulating biomarker for early-stage lung cancer

There is an unmet need for circulating biomarkers that can detect early-stage lung cancer. Here we show that a variant form of the nuclear matrix-associated DNA replication factor Ciz1 is present in 34/35 lung tumors but not in adjacent tissue, giving rise to stable protein quantifiable by Western blot in less than a microliter of plasma from lung cancer patients. In two independent sets, with 170 and 160 samples, respectively, variant Ciz1 correctly identified patients who had stage 1 lung cancer with clinically useful accuracy. For set 1, mean variant Ciz1 level in individuals without diagnosed tumors established a threshold that correctly classified 98% of small cell lung cancers (SCLC) and non-SCLC patients [receiver operator characteristic area under the curve (AUC) 0.958]. Within set 2, comparison of patients with stage 1 non-SCLC with asymptomatic age-matched smokers or individuals with benign lung nodules correctly classified 95% of patients (AUCs 0.913 and 0.905), with overall specificity of 76% and 71%, respectively. Moreover, using the mean of controls in set 1, we achieved 95% sensitivity among patients with stage 1 non-SCLC patients in set 2 with 74% specificity, demonstrating the robustness of the classification. RNAi-mediated selective depletion of variant Ciz1 is sufficient to restrain the growth of tumor cells that express it, identifying variant Ciz1 as a functionally relevant driver of cell proliferation in vitro and in vivo. The data show that variant Ciz1 is a strong candidate for a cancer-specific single marker capable of identifying early-stage lung cancer within at-risk groups without resort to invasive procedures.

Chemotherapy for pulmonary large cell neuroendocrine carcinoma: similar to that for small cell lung cancer or non-small cell lung cancer?

BACKGROUND

There is controversy regarding palliative chemotherapy for large cell neuroendocrine carcinoma (LCNEC). We evaluated whether advanced LCNEC should be treated similarly to small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

The clinical reports and tumor specimens of 45 consecutive patients who were diagnosed with advanced LCNEC were reviewed. They were divided into SCLC (n=11) and NSCLC regimen groups (n=34) according to first-line chemotherapeutic regimens.

RESULTS

Most patients were male (96%) and smokers (93%) with a median age of 64 years. Neuroendocrine differentiation was established in 42 (93%) tumors by immunohistochemical analyses. Regarding the efficacy of first-line chemotherapy in the SCLC and NSCLC regimen groups, the response rates were 73% and 50% (P=0.19), and the median progression-free survival times were 6.1 and 4.9 months (P=0.41), respectively. The difference in overall survival between the two treatment groups was 7.3 months (16.5 vs. 9.2 months, P=0.10). There was also a considerable difference in the type and efficacy of salvage chemotherapeutic regimens between the two groups: salvage regimens with irinotecan, platinum, or taxanes were commonly used with relatively high objective responses in the SCLC regimen group, whereas frequently used agents in the NSCLC regimen group such as pemetrexed, gefitinib, or erlotinib were associated with no objective response.

CONCLUSION

Regarding palliative chemotherapy for advanced LCNEC, treatment similar to SCLC is more appropriate than NSCLC.

Molecular and cellular biology of neuroendocrine lung tumors: evidence for separate biological entities

Pulmonary neuroendocrine tumors (NETs) are traditionally described as comprising a spectrum of neoplasms, ranging from low grade typical carcinoids (TCs) via the intermediate grade atypical carcinoids (ACs) to the highly malignant small cell lung cancers (SCLCs) and large cell neuroendocrine carcinomas (LCNECs). Recent data, however, suggests that two categories can be distinguished on basis of molecular and clinical data, i.e. the high grade neuroendocrine (NE) carcinomas and the carcinoid tumors. Bronchial carcinoids and SCLCs may originate from the same pulmonary NE precursor cells, but a precursor lesion has only been observed in association with carcinoids, termed diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. The occurrence of mixed tumors exclusively comprising high grade NE carcinomas also supports a different carcinogenesis for these two groups. Histopathologically, high grade NE lung tumors are characterized by high mitotic and proliferative indices, while carcinoids are defined by maximally 10 mitoses per 2mm(2) (10 high-power fields) and rarely have Ki67-proliferative indices over 10%. High grade NE carcinomas are chemosensitive tumors, although they usually relapse. Surgery is often not an option due to extensive disease at presentation and early metastasis, especially in SCLC. Conversely, carcinoids are often insensitive to chemo- and radiation therapy, but cure can usually be achieved by surgery. A meta-analysis of comparative genomic hybridization studies performed for this review, as well as gene expression profiling data indicates separate clustering of carcinoids and carcinomas. Chromosomal aberrations are much more frequent in carcinomas, except for deletion of 11q, which is involved in the whole spectrum of NE lung tumors. Deletions of chromosome 3p are rare in carcinoids but are a hallmark of the high grade pulmonary NE carcinomas. On the contrary, mutations of the multiple endocrine neoplasia type 1 (MEN1) gene are restricted to carcinoid tumors. Many of the differences between carcinoids and high grade lung NETs can be ascribed to tobacco consumption, which is strongly linked to the occurrence of high grade NE carcinomas. Smoking causes p53 mutations, very frequently present in SCLCs and LCNECs, but rarely in carcinoids. It further results in other early genetic events in SCLCs and LCNECs, such as 3p and 17p deletions. Smoking induces downregulation of E-cadherin and associated epithelial to mesenchymal transition. Also, high grade lung NETs display higher frequencies of aberrations of the Rb pathway, and of the intrinsic and extrinsic apoptotic routes. Carcinoid biology on the other hand is not depending on cigarette smoke intake but rather characterized by aberrations of other specific genetic events, probably including Menin or its targets and interaction partners. This results in a gradual evolution, most likely from proliferating pulmonary NE cells via hyperplasia and tumorlets towards classical carcinoid tumors. We conclude that carcinoids and high grade NE lung carcinomas are separate biological entities and do not comprise one spectrum of pulmonary NETs. This implies the need to reconsider both diagnostic as well as therapeutic approaches for these different groups of malignancies.

Emerging drugs for small cell lung cancer--an update

INTRODUCTION

Small cell lung cancer (SCLC) is a biologically complex tumor whose medical treatment has remained largely unchanged over the last 30 years. The frustration for the invariably negative results reported in the early 2000s in clinical studies investigating new agents for this disease have contributed to the little interest shown by pharmaceutical industries in funding SCLC research. However, recent advances in the molecular understanding of the oncogenic mechanisms underlying SCLC have renewed the attraction for the clinical development of novel active drugs for the treatment of this challenging disease.

AREAS COVERED

The authors briefly touch on the most promising agents under clinical development for the treatment of SCLC, either chemotherapeutic or targeted drugs. Relevant and recent (2 years) studies obtained through Pubmed literature research or released at International scientific meetings are presented.

EXPERT OPINION

The data discussed herein provide evidence in support of the fact that only rationally designed clinical trials including relevant translational research may lead to successful results. Therefore, a thoughtful change in trial construction is crucial for the approval of new active drugs for this orphan disease.

A clinicopathological study of peripheral, small-sized high-grade neuroendocrine tumours of the lung: differences between small-cell lung carcinoma and large-cell neuroendocrine carcinoma

OBJECTIVES

Small-cell lung carcinoma (SCLC) and large-cell neuroendocrine carcinoma (LCNEC) are categorized as high-grade neuroendocrine tumours because of their poor prognosis compared with those of other neuroendocrine tumours of the lung. There have been no clinicopathological studies focusing on small-sized high-grade neuroendocrine tumours. We analysed clinicopathological features of peripheral, small-sized high-grade neuroendocrine tumours of the lung retrospectively.

METHODS

A total of 28 patients with peripheral, small-sized tumours (maximum diameter of 3.0 cm) of SCLC and LCNEC underwent surgical resection in our hospital and were enrolled in this study.

RESULTS

Of 28 tumours, 18 were SCLC and 10 were LCNEC. In terms of serum tumour marker levels, carcinoembryonic antigen was elevated in 50% of both types of tumour, and progastrin-releasing peptide was elevated in 28% of SCLC and 10% of LCNEC. With regard to preoperative diagnosis, only seven SCLC cases were correctly diagnosed as SCLC, but no LCNEC case was correctly diagnosed before surgery. Lymphatic involvement was significantly more frequent in SCLC than in LCNEC (P = 0.013). Although adjuvant chemotherapy was carried out more frequently in the patients with SCLC than LCNEC, the recurrence rate after the standard surgery was significantly higher in the patients with SCLC than LCNEC (P = 0.0037). There was a significant difference between SCLC and LCNEC in terms of overall survival in clinical-stage IA small-sized tumours (P = 0.029).

CONCLUSIONS

In peripheral, small-sized high-grade neuroendocrine tumours, there are several clinicopathological differences between SCLC and LCNEC. This study suggested that the prognosis of patients with LCNEC tended to be better than for those with SCLC in small-sized tumours.

Classification of microarrays; synergistic effects between normalization, gene selection and machine learning

Background

Machine learning is a powerful approach for describing and predicting classes in microarray data. Although several comparative studies have investigated the relative performance of various machine learning methods, these often do not account for the fact that performance (e.g. error rate) is a result of a series of analysis steps of which the most important are data normalization, gene selection and machine learning.

Results

In this study, we used seven previously published cancer-related microarray data sets to compare the effects on classification performance of five normalization methods, three gene selection methods with 21 different numbers of selected genes and eight machine learning methods. Performance in term of error rate was rigorously estimated by repeatedly employing a double cross validation approach. Since performance varies greatly between data sets, we devised an analysis method that first compares methods within individual data sets and then visualizes the comparisons across data sets. We discovered both well performing individual methods and synergies between different methods.

Conclusion

Support Vector Machines with a radial basis kernel, linear kernel or polynomial kernel of degree 2 all performed consistently well across data sets. We show that there is a synergistic relationship between these methods and gene selection based on the T-test and the selection of a relatively high number of genes. Also, we find that these methods benefit significantly from using normalized data, although it is hard to draw general conclusions about the relative performance of different normalization procedures.

Clinical features of unresectable high-grade lung neuroendocrine carcinoma diagnosed using biopsy specimens

BACKGROUND

The overall clinicopathological features or the optimal therapy for large cell neuroendocrine carcinoma (LCNEC) have yet to be defined, because LCNEC has not been studied in the same depth as had small cell lung carcinoma (SCLC) in both clinical and biological standpoints. The aim of this study was to elucidate the clinical features of high-grade neuroendocrine carcinoma (HGNEC)-probable LCNEC diagnosed by biopsy, and compare therapeutic efficacy with patients with SCLC.

METHODS

We retrospectively examined the chart of total of 25 patients who underwent chemotherapy or chemoradiotherapy as initial therapy for a histologic diagnosis of HGNEC-probable LCNEC, using biopsy samples and compared their data with those of 180 patients with SCLC. We analyzed their responses to chemotherapy and/or radiation therapy and survival outcomes.

RESULTS

In 25 patients with HGNEC-probable LCNEC, 18 patients initially received chemotherapy (17 (94%) of whom received platinum-based chemotherapy) with an overall response rate (ORR) of 61%. The remaining 7 patients received chemoradiotherapy with an ORR of 86%, and 12 of the 25 patients who received second-line chemotherapy had an ORR of 17%. A total of 101 patients with SCLC who initially received chemotherapy had an ORR of 63%, and 79 patients who initially received chemoradiotherapy had an ORR of 98%, and 102 of the 180 patients who received second-line chemotherapy had an ORR of 45%. The 1-year overall survival rate for patients with stage IV HGNEC-probable LCNEC (n=13) and those with ED-SCLC (n=80) was 34% and 49%, respectively (p=0.84).

CONCLUSION

The overall response rate to initial treatment and the survival outcomes of HGNEC-probable LCNEC were comparable to those of SCLC, but the effectiveness of second-line chemotherapy appeared to differ between the 2 groups.