Combined small cell lung carcinomas: genotypic and immunophenotypic analysis of the separate morphologic components

The therapeutic effect of DX2 inhibition in nicotine-induced lung cancer progression

Alternative splicing products of AIMP2 and AIMP2-DX2 (DX2) have been reported to be associated with human lung cancer. In fact, DX2 expression is elevated in human lung cancers, and DX2 transgenic mice also develop lung cancer, in particular small cell lung cancer (SCLC). However, the mechanism by which DX2 is induced during cancer progression has not been clearly elucidated. Here, we show that DX2 is induced by nicotine, the main component of smoking-related chemicals, which can stabilize the human epidermal growth factor receptor 2 (HER2) protein and transcriptionally increase sonic hedgehog (Shh). Indeed, nicotine showed tumorigenicity via DX2 by promoting spheroid formation and in vivo lung and kidney cancer progression. Moreover, the elimination of DX2 using small interfering RNA (siRNA) or an optimized inhibitor (SNU-14) blocked the induction of HER2 and Shh and completely suppressed tumor sphere formation in response to nicotine. These results indicate that DX2 is critical for lung cancer progression, and a specific DX2 inhibitor would be useful for the treatment of human cancers, including SCLC and non-SCLC (NSCLC).

Clinical features and prognostic factors of IV combined small cell lung cancer: A propensity score matching analysis

BACKGROUND

Nowadays, the characteristics and treatment of combined small-cell lung carcinoma (CSCLC) remain controversial. This study aimed to analyze the features of clinical demographics, survival outcomes and treatment modalities among IV CSCLC, IV SCLC and IV NSCLC, to provide more evidence for the study of IV CSCLC.

METHODS

All CSCLC, SCLC and NSCLC patient data were obtained from the SEER database (2010-2020). Pearson's χ2 test was used to compare the differences in clinical characteristics. Propensity score matching (PSM) was utilized to balance the bias of the variables between patients. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify prognostic factors. KM analysis was used to calculate survival. Adjusted analyses for the primary outcome of different treatment modalities of IV CSCLC, IV SCLC and IV NSCLC were performed using Cox regression models.

RESULTS

A total of 493 patients with IV CSCLC, 35503 patients with SCLC, 122807 patients with IV NSCLC were included in this study. The demographic characteristics and tumor characteristics of the three groups were different. Before PSM, there were significant differences in OS and CSS among IV CSCLC, IV SCLC and IV NSCLC, After PSM, there was a significant difference in OS and CSS between the IV CSCLC and IV NSCLC. Risk/protective factors for OS and CSS were different in three groups. Chemotherapy, radiotherapy, and surgery can improve IV CSCLC's survival time. The combination of surgery and chemoradiotherapy treatment group for patients with IV CSCLC demonstrated best OS compared to control treatment groups, and the surgery combined chemotherapy treatment group exhibited the best CSS. Additionally, for select patients with stage IV CSCLC who have missed the window for surgical intervention at the time of initial diagnosis, chemoradiotherapy presents a viable and effective treatment option.

CONCLUSIONS

The clinical characteristics IV CSCLC, IV SCLC and IV NSCLC were significantly different. The prognosis for IV CSCLC is notably poorer than IV NSCLC, similar to IV SCLC. Surgery combined therapy emerged as the preferred treatment modalities and chemoradiotherapy was a good choice for patients who have lost the indication of surgery for patients diagnosed with IV CSCLC.

Exploring the prognostic impact of differences in treatment strategies for SCLC with different histologies and prognostic factors for C-SCLC: A SEER population-based study

Background

Combined small cell lung cancer (C-SCLC) is a rare type of small cell lung cancer (SCLC), and it is controversial whether to choose the same treatment regimen as SCLC due to its multiple histologic components.

Study methods and results

Records of patients with small cell lung cancer diagnosed between 2010 and 2020 were extracted using the SEER database. The OS of patients with different histological types under the same staging and treatment regimen was analyzed. It was found that early-stage (stage IA-IIA) surgical treatment, systemic chemotherapy alone, and chemoradiotherapy were more efficacious than C-SCLC and P-SCLC in patients with limited-stage (P = 0.054, P = 0.001, P = 0.019). In patients with extensive staging, the OS of patients with systemic chemotherapy regimens differed (P = 0.045) and was better in C-SCLC than in P-SCLC. We further explored the treatment strategy for patients with C-SCLC, which was shown by a COX regression model based on prognostic factors screened by Random Forest and LASSO regression models. Surgery, radiotherapy, and chemotherapy would be beneficial for survival. In a subgroup analysis based on stage and treatment regimen, it was shown that patients with early staging (stage IA-IIA) had a better prognosis with surgery (P < 0.001); in patients with extensive staging, chemoradiotherapy was favorable to the patient's prognosis (P = 0.022).

Conclusion

Both limited-stage and extensive-stage C-SCLC patients are more sensitive to chemotherapy than P-SCLC patients. Patients with C-SCLC who have access to surgery should undergo surgery as early as possible, while chemoradiotherapy is recommended for patients with extensive staging. Patient age, gender, tumor size, surgery, chemotherapy, radiotherapy, and metastasis may individually affect patient prognosis.

Clonal Origin and Lineage Ambiguity in Mixed Neuroendocrine Carcinoma of the Uterine Cervix

Small-cell neuroendocrine carcinoma (SCNEC) of the cervix is a rare disease characterized by a high incidence of mixed tumors with other types of cancer. The mechanism underlying this mixed phenotype is not well understood. This study established a panel of organoid lines from patients with SCNEC of the cervix and ultimately focused on one line, which retained a mixed tumor phenotype, both in vitro and in vivo. Histologically, both organoids and xenograft tumors showed distinct differentiation into either SCNEC or adenocarcinoma in some regions and ambiguous differentiation in others. Tracking single cells indicated the existence of cells with bipotential differentiation toward SCNEC and adenocarcinomas. Single-cell transcriptional analysis identified three distinct clusters: SCNEC-like, adenocarcinoma-like, and a cluster lacking specific differentiation markers. The expression of neuroendocrine markers was enriched in the SCNEC-like cluster but not exclusively. Human papillomavirus 18 E6 was enriched in the SCNEC-like cluster, which showed higher proliferation and lower levels of the p53 pathway. After treatment with anticancer drugs, the expression of adenocarcinoma markers increased, whereas that of SCNEC decreased. Using a reporter system for keratin 19 expression, changes in the differentiation of each cell were shown to be associated with the shift in differentiation induced by drug treatment. These data suggest that mixed SCNEC/cervical tumors have a clonal origin and are characterized by an ambiguous and flexible differentiation state.

Genomic and transcriptomic profiling of combined small-cell lung cancer through microdissection: unveiling the transformational pathway of mixed subtype

BACKGROUND

Combined small-cell lung carcinoma (cSCLC) represents a rare subtype of SCLC, the mechanisms governing the evolution of cancer genomes and their impact on the tumor immune microenvironment (TIME) within distinct components of cSCLC remain elusive.

METHODS

Here, we conducted whole-exome and RNA sequencing on 32 samples from 16 cSCLC cases.

RESULTS

We found striking similarities between two components of cSCLC-LCC/LCNEC (SCLC combined with large-cell carcinoma/neuroendocrine) in terms of tumor mutation burden (TMB), tumor neoantigen burden (TNB), clonality structure, chromosomal instability (CIN), and low levels of immune cell infiltration. In contrast, the two components of cSCLC-ADC/SCC (SCLC combined with adenocarcinoma/squamous-cell carcinoma) exhibited a high level of tumor heterogeneity. Our investigation revealed that cSCLC originated from a monoclonal source, with two potential transformation modes: from SCLC to SCC (mode 1) and from ADC to SCLC (mode 2). Therefore, cSCLC might represent an intermediate state, potentially evolving into another histological tumor morphology through interactions between tumor and TIME surrounding it. Intriguingly, RB1 inactivation emerged as a factor influencing TIME heterogeneity in cSCLC, possibly through neoantigen depletion.

CONCLUSIONS

Together, these findings delved into the clonal origin and TIME heterogeneity of different components in cSCLC, shedding new light on the evolutionary processes underlying this enigmatic subtype.

Molecular subtype expression and genomic profiling differ between surgically resected pure and combined small cell lung carcinoma

A new molecular subtype classification method has been proposed for small cell lung carcinoma (SCLC). However, little is known about the differences between the pure (P-SCLC) and combined subtypes (C-SCLC). We aimed to compare the molecular subtype expression and genomic profiling in terms of clinical relevance between the two groups. 154 surgically resected SCLCs were analyzed for protein expression of four subtypes (ASCL1, NEUROD1, POU2F3, and YAP1) and two predictive markers (DLL3 and MYC) by immunohistochemistry (IHC). We also performed whole exome sequencing of 60 samples to examine genomic profiles. A total of 113 patients with P-SCLC and 41 with C-SCLC were included. In P-SCLC and C-SCLC, the expression of these markers was 78.8% and 41.5%, 98.2% and 97.6%, 42.5% and 51.2%, 38.9% and 85.4%, 85.0% and 68.3%, and 24.8% and 34.1%, respectively. ASCL1 and DLL3 were highly expressed in P-SCLC (p = 0.000 and p = 0.021, respectively), and YAP1 expression was significantly enriched in C-SCLC (p = 0.000). NGS results, including 45 P-SCLCs and 15 C-SCLCs, indicated that EGFR gene mutations were mostly observed in C-SCLCs (p = 0.000). C-SCLC showed higher CNA burden and wGII than P-SCLC (p < 0.01 and p < 0.05); conversely, P-SCLC had higher TMB burden and SDI (p < 0.05 and p < 0.05). YAP1 expression was associated with poor prognosis in P-SCLC but with favorable prognosis in C-SCLC. P-SCLC and C-SCLC are heterogeneous diseases characterized by different molecular subtype expressions and genomic profiles. Our data provide a basis for adopting histological subtype-based treatments, and further prospective studies are required to confirm our conclusions.

Patient-derived spheroids and patient-derived organoids simulate evolutions of lung cancer

Cancer cells harbor many genetic mutations and gene expression profiles different from normal cells. Patient-derived cancer cells (PDCC) are preferred materials in cancer study. We established patient-derived spheroids (PDSs) and patient-derived organoids (PDOs) from PDCCs isolated from the malignant pleural effusion in 8 patients. The morphologies suggested that PDSs may be a model of local cancer extensions, while PDOs may be a model of distant cancer metastases. The gene expression profiles differed between PDSs and PDOs: Gene sets related to inflammatory responses and EMT were antithetically regulated in PDSs or in PDOs. PDSs demonstrated an attenuation of the pathways that contribute to the enhancement of transforming growth factor beta (TGF-β) induced epithelial mesenchymal transition (EMT), while PDOs demonstrated an attenuation of it. Taken together, PDSs and PDOs have differences in both the interaction to the immune systems and to the stroma. PDSs and PDOs will provide a model system that enable intimate investigation of the behavior of cancer cells in the body.

Whole-Process Treatment of Combined Small Cell Lung Cancer Initially Diagnosed as "Lung Squamous Cell Carcinoma": A Case Report and Review of the Literature

The rarity and complexity of histology lead to the low diagnosis rate and high misdiagnosis rate of combined small cell lung cancer (C-SCLC). Nowadays, C-SCLC has no commonly recommended therapeutic regimen, mainly conforming to SCLC treatment. Here, we report a patient initially diagnosed as IIIA "lung squamous cell carcinoma" by a small specimen. Radical resection was achieved after neoadjuvant immunochemotherapy, and the final surgical pathology was C-SCLC containing three different histological components. Moreover, in the literature review, we explored the therapeutic effect of neoadjuvant immunotherapy in C-SCLC, expounded the therapeutic conflicts among heterogeneous components, and analyzed the pathology complexity at the tissue, cell, and molecule levels in-depth, including possible genetic characteristics, origin, and evolution by next-generation sequencing (NGS).

In-depth molecular analysis of combined and co-primary pulmonary large cell neuroendocrine carcinoma and adenocarcinoma

Up to 14% of large cell neuroendocrine carcinomas (LCNECs) are diagnosed in continuity with nonsmall cell lung carcinoma. In addition to these combined lesions, 1% to 7% of lung tumors present as co-primary tumors with multiple synchronous lesions. We evaluated molecular and clinicopathological characteristics of combined and co-primary LCNEC-adenocarcinoma (ADC) tumors. Ten patients with LCNEC-ADC (combined) and five patients with multiple synchronous ipsilateral LCNEC and ADC tumors (co-primary) were included. DNA was isolated from distinct tumor parts, and 65 cancer genes were analyzed by next generation sequencing. Immunohistochemistry was performed including neuroendocrine markers, pRb, Ascl1 and Rest. Pure ADC (N = 37) and LCNEC (N = 17) cases were used for reference. At least 1 shared mutation, indicating tumor clonality, was found in LCNEC- and ADC-parts of 10/10 combined tumors but only in 1/5 co-primary tumors. A range of identical mutations was observed in both parts of combined tumors: 8/10 contained ADC-related (EGFR/KRAS/STK11 and/or KEAP1), 4/10 RB1 and 9/10 TP53 mutations. Loss of pRb IHC was observed in 6/10 LCNEC- and 4/10 ADC-parts. The number and intensity of expression of Ascl1 and neuroendocrine markers increased from pure ADC (low) to combined ADC (intermediate) and combined and pure LCNEC (high). The opposite was true for Rest expression. In conclusion, all combined LCNEC-ADC tumors were clonally related indicating a common origin. A relatively high frequency of pRb inactivation was observed in both LCNEC- and ADC-parts, suggesting an underlying role in LCNEC-ADC development. Furthermore, neuroendocrine differentiation might be modulated by Ascl1(+) and Rest(-) expression.

Case Report: Combined Small Cell Lung Carcinoma With Pulmonary Adenocarcinoma

Background

Combined small cell lung carcinoma is defined as cancer tissues that mainly contain small cell lung cancer (SCLC) components with non-SCLC (NSCLC) histopathological types. The most common part of NSCLC is squamous cell carcinoma or large cell carcinoma. Combined SCLC (CSCLC) contains adenocarcinoma is extremely rare.

Case Presentation

We reported a case with surgically treated diagnosed as CSCLC with adenocarcinoma in an elderly and we summarized the clinical features of this disease. The patient has remained well for over 2 weeks after the treatment.

Conclusion

There are still few research reports on CSCLC. Since the survival time of patients with advanced CSCLC is shorter than that of simple SCLC, the recommended treatment for CSCLC is early detection and early surgery. In order to facilitate preoperative diagnosis and avoid misdiagnosis of such rare diseases, more cases need to be reported.

Pathology and Classification of SCLC

Simple Summary

Small cell lung carcinoma (SCLC), is a high-grade neuroendocrine carcinoma defined by its aggressiveness, poor differentiation, and somber prognosis. This review highlights current pathological concepts including classification, immunohistochemistry features, and differential diagnosis. Additionally, we summarize the current knowledge of the immune tumor microenvironment, tumor heterogeneity, and genetic variations of SCLC. Recent comprehensive genomic research has improved our understanding of the diverse biological processes that occur in this tumor type, suggesting that a new era of molecular-driven treatment decisions is finally foreseeable for SCLC patients.

Abstract

Lung cancer is consistently the leading cause of cancer-related death worldwide, and it ranks as the second most frequent type of new cancer cases diagnosed in the United States, both in males and females. One subtype of lung cancer, small cell lung carcinoma (SCLC), is an aggressive, poorly differentiated, and high-grade neuroendocrine carcinoma that accounts for 13% of all lung carcinomas. SCLC is the most frequent neuroendocrine lung tumor, and it is commonly presented as an advanced stage disease in heavy smokers. Due to its clinical presentation, it is typically diagnosed in small biopsies or cytology specimens, with routine immunostaining only. However, immunohistochemistry markers are extremely valuable in demonstrating neuroendocrine features of SCLC and supporting its differential diagnosis. The 2015 WHO classification grouped all pulmonary neuroendocrine carcinomas in one category and maintained the SCLC combined variant that was previously recognized. In this review, we explore multiple aspects of the pathologic features of this entity, as well as clinically relevant immunohistochemistry markers expression and its molecular characteristics. In addition, we will focus on characteristics of the tumor microenvironment, and the latest pathogenesis findings to better understand the new therapeutic options in the current era of personalized therapy.

Comprehensive genomic profiling of combined small cell lung cancer

Background

Combined small cell lung cancer (CSCLC) is an uncommon and heterogeneous subtype of small cell lung cancer (SCLC). However, there is limited data concerning the different molecular changes and clinical features in CSCLC compared to pure SCLC.

Methods

The clinical and pathological characteristics of pure SCLC and CSCLC patients were analyzed. Immunohistochemistry and microdissection were performed to isolate the CSCLC components. Further molecular analysis was carried out by next-generation sequencing (NGS) in 12 CSCLC and 30 pure SCLC.

Results

There were no significant differences in clinical features between CSCLC and pure SCLC. Overall survival (OS) of CSCLC patients was worse than pure SCLC (P=0.005). NGS results indicated that TP53 and RB1 were the most frequently mutated genes in both CSCLC (83.33% and 66.67%) and pure SCLC (80.00% and 63.33%) groups. However, less than 10% common mutations were found in both CSCLC and pure SCLC. When analyzing the data of SCLC and non-small cell lung cancer (NSCLC) components of CSCLC, more than 50% common mutations, and identical genes with mutations were detected. Moreover, there were also common biological processes and signaling pathways identified in CSCLC and pure SCLC, in addition to SCLC and NSCLC components.

Conclusions

There were no significant differences in terms of clinical features between CSCLC and pure SCLC. However, the prognosis for CSCLC was worse than pure SCLC. NGS analysis suggested that CSCLC components might derive from the same pluripotent single clone with common initial molecular alterations and subsequent acquisitions of other genetic mutations.

Cancer Plasticity: The Role of mRNA Translation

Tumor progression is associated with dedifferentiated histopathologies concomitant with cancer cell survival within a changing, and often hostile, tumor microenvironment. These processes are enabled by cellular plasticity, whereby intracellular cues and extracellular signals are integrated to enable rapid shifts in cancer cell phenotypes. Cancer cell plasticity, at least in part, fuels tumor heterogeneity and facilitates metastasis and drug resistance. Protein synthesis is frequently dysregulated in cancer, and emerging data suggest that translational reprograming collaborates with epigenetic and metabolic programs to effectuate phenotypic plasticity of neoplasia. Herein, we discuss the potential role of mRNA translation in cancer cell plasticity, highlight emerging histopathological correlates, and deliberate on how this is related to efforts to improve understanding of the complex tumor ecology.

Pathological transition as the arising mechanism for drug resistance in lung cancer

Despite the tremendous efforts for improving therapeutics of lung cancer patients, its prognosis remains disappointing. This can be largely attributed to the lack of comprehensive understanding of drug resistance leading to insufficient development of effective therapeutics in clinic. Based on the current progresses of lung cancer research, we classify drug resistance mechanisms into three different levels: molecular, cellular and pathological level. All these three levels have significantly contributed to the acquisition and evolution of drug resistance in clinic. Our understanding on drug resistance mechanisms has begun to change the way of clinical practice and improve patient prognosis. In this review, we focus on discussing the pathological changes linking to drug resistance as this has been largely overlooked in the past decades.

Are neuroendocrine negative small cell lung cancer and large cell neuroendocrine carcinoma with WT RB1 two faces of the same entity?

Until recently, small cell lung cancer (SCLC) was described as SCLC and SCLC variant, based upon cellular morphology and loss of neuroendocrine markers in the SCLC variant. However, based on recent research advances, driven in part by the increase in comprehensive genomic data, it has become clear that there are multiple SCLC subtypes including an ASCL1 and NEUROD1 low, YAP1 high (SCLC-Y) subtype enriched for WT RB1. Comparing morphological and other features of this SCLC subtype to neuroendocrine negative RB1, KEAP1, STK11 WT LCNEC raises a number of important questions with diagnostic and therapeutic implications.

Combined small-cell lung carcinoma

Currently, studies assessing combined small-cell lung carcinoma (C-SCLC) are relatively scarce and limited. Indeed the clinicopathological features, treatment, and prognosis of patients with C-SCLC have not been fully determined. The incidence of C-SCLC ranges from 5%–28% in different studies, which is related to the specimen types used. The clinical features of C-SCLC are characterized by the higher proportion of peripheral locations, earlier stage, and more opportunity to experience surgery. Surgery is more important for earlier stage C-SCLC. There have been no recent changes in the chemotherapy of C-SCLC, which is recommended by the treatment guidelines for SCLC, neither showing survival benefit from the 3-agent regimen. Meanwhile, the efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in EGFR-mutated C-SCLC patients remains inconclusive. This review focuses on clinical and pathologic features, prognostic factors, and optimized treatment model in C-SCLC.

Tonsillar Small Cell Carcinoma: Potential Contribution of Human Papillomavirus

Patient: Female, 64

Final Diagnosis: Small cell carcinoma of the tonsil

Symptoms: Sore throat

Medication: —

Clinical Procedure: —

Specialty: Oncology

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

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

Combined Small Cell Carcinoma of the Lung: Is It a Single Entity?

BACKGROUND

SCLC accounts for 15% and 20% of all lung cancers, with combined SCLC (CSCLC) comprising 2% to 5%. Little is known about the clinical characteristics and molecular changes associated with the various histologic components.

METHODS

A total of 205 SCLC cases were resected between 2005 and 2015. Clinical and pathologic features were analyzed. All CSCLC cases were confirmed by histologic examination and immunohistochemistry. The individual components were microdissected using a novel automated dissection system, and DNA was extracted and subjected to targeted exome sequencing.

RESULTS

A total of 10 cases of CSCLC were identified out of 170 cases with adequate histologic material; squamous cell carcinoma comprised the second component in half of these (n = 5). There were no significant differences between CSCLC and pure SCLC with respect to clinical features. The median follow-up time was 36 months. The median survival times of patients with pure SCLC and CSCLC were 58 months and 26 months, respectively (p = 0.030). The different components of three cases of CSCLC were deemed adequate for microdissection and sequencing. Approximately 75% of the identified somatic mutations were present in both components. There were also 15 gene mutations or six amplifications unique to only one of the components.

CONCLUSIONS

We identified no significant clinical or pathologic differences between pure SCLC and CSCLC; CSCLC was associated with decreased overall survival compared with pure SCLC. The histologic components of CSCLC had high genetic concordance but also showed divergent genotypes. These findings may suggest a common precursor with subsequent acquisition of oncogenic changes in CSCLC.

Correlation between histone acetylation and expression of Notch1 in human lung carcinoma and its possible role in combined small-cell lung carcinoma

Combined small-cell lung carcinoma (cSCLC) is composed of small-cell lung carcinoma (SCLC) admixed with non-small-cell lung carcinoma (NSCLC). Evaluating the molecular differences between SCLC and NSCLC could lead to a better understanding of the pathogenesis of such neoplasms. Therefore, in this study, we investigated the correlation between histone acetylation and Notch1 expression in lung carcinoma. Using chromatin immunoprecipitation (ChIP) assay, we measured the level of acetylated histone H3 around the promoter region of Notch1 in SCLC and NSCLC cells. We then treated SCLC cells with trichostatin A (TSA) and characterized the level of histone H3 acetylation at Notch1. In addition, TSA-treated cells were injected into immune-compromised mice, for analysis of the ex vivo tumor xenograft phenotype. The level of acetylated histone H3 surrounding the Notch1 promoter was lower in lung cancer cells not expressing Notch1. Tumors originated from TSA-treated SCLC cells occasionally formed an epithelial-like glandular arrangement of cells; with Notch1 expression and decreased expression of neuroendocrine (NE) markers. Histone deacetylation around the promoter region of Notch1 inhibits Notch1 protein expression in SCLC and the restoration of Notch1 expression in SCLC leads to the concurrent appearance of epithelial-like areas within the SCLC, which could provide a possible mechanism for histogenesis of cSCLC.

Clinical outcomes of surgically resected combined small cell lung cancer: a two-institutional experience

BACKGROUND

The combined small cell lung cancer (c-SCLC) was rare and its clinicopathological characteristics had not been thoroughly described. The aim of this study was to determine prognostic factors and survival in c-SCLC patients.

METHODS

Clinical records of patients with c-SCLC who underwent surgery between January 2009 and December 2013 in two institutions were retrospectively reviewed.

RESULTS

Ninety-seven patients were identified. The most common pathology was combined SCLC and large cell neuroendocrine carcinoma (LCNEC, N=46), followed by combined SCLC and squamous cell carcinoma (SCC) (N=32), combined SCLC and adenocarcinoma (AC) (N=12), and combined SCLC and adenosquamous carcinoma (ASC) (N=7). The overall survival (OS) rates of the entire cohort were 42.4% and 35.2% at 3 and 5 years, respectively. Multivariate analysis identified sex [female vs. male, hazards ratio (HR) =0.38; 95% confidence interval (CI): 0.19-0.79; P=0.010], age (<53 vs. >53 years, HR =0.28; 95% CI: 0.09-0.81; P=0.019), performance status (<2 vs. >2, HR =0.08; 95% CI: 0.02-0.32; P<0.001), combined non-small cell lung cancer (NSCLC) components (LCNEC vs. non-LCNEC, HR =3.00; 95% CI: 1.03-8.76; P=0.045), adjuvant therapy (yes vs. no, HR =0.33; 95% CI: 0.17-0.67; P=0.002) as significantly prognostic factors of OS in patients with complete resection and lymphadenectomy.

CONCLUSIONS

The mixed NSCLC components within c-SCLCs had a significant influence on the survival. Compared with surgery alone, adjuvant therapy was associated with significantly improved survival in patients with complete resection and lymphadenectomy.

Mixed Neuroendocrine-Nonneuroendocrine Neoplasms (MiNENs): Unifying the Concept of a Heterogeneous Group of Neoplasms

The wide application of immunohistochemistry to the study of tumors has led to the recognition that epithelial neoplasms composed of both a neuroendocrine and nonneuroendocrine component are not as rare as traditionally believed. It has been recommended that mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are classified as only those in which either component represents at least 30 % of the lesion but this cutoff has not been universally accepted. Moreover, since their pathogenetic and clinical features are still unclear, mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are not included as a separate clinicopathological entity in most WHO classifications, although they have been observed in virtually all organs. In the WHO classification of digestive tumors, mixed neuroendocrine-nonneuroendocrine neoplasm is considered a specific type and is defined as mixed adenoneuroendocrine carcinoma, a definition that has not been accepted for other organs. In fact, this term does not adequately convey the morphological and biological heterogeneity of digestive mixed neoplasms and has created some misunderstanding among both pathologists and clinicians. In the present study, we have reviewed the literature on mixed neuroendocrine-nonneuroendocrine epithelial neoplasms reported in the pituitary, thyroid, nasal cavity, larynx, lung, digestive system, urinary system, male and female genital organs, and skin to give the reader an overview of the most important clinicopathological features and morphological criteria for diagnosing each entity. We also propose to use the term "mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN)" to define and to unify the concept of this heterogeneous group of neoplasms, which show different characteristics mainly depending on the type of neuroendocrine and nonneuroendocrine components.

Nrf2 and Notch Signaling in Lung Cancer: Near the Crossroad

The transcription factor Nrf2 (NF-E2 related factor 2) is a master regulator of the cell antioxidant response associated with tumor growth and resistance to cytotoxic treatments. In particular, Nrf2 induces upregulation of cytoprotective genes by interacting with the closely situated AREs (Antioxidant Response Elements) in response to endogenous or exogenous stress stimuli and takes part to several oncogenic signaling pathways. Among these, the crosstalk with Notch pathway has been shown to enhance cytoprotection and maintenance of cellular homeostasis, tissue organization by modulating cell proliferation kinetics, and stem cell self-renewal in several organs. The role of Notch and Nrf2 related pathways in tumorigenesis is highly variable and when they are both abnormally activated they can synergistically cause neoplastic proliferation by promoting cell survival, differentiation, invasion, and metastases. NFE2L2, KEAP1, and NOTCH genes family appear in the list of significantly mutated genes in tumors in both combined and individual sets, supporting the crucial role that the aberrant Nrf2-Notch crosstalk might have in cancerogenesis. In this review, we summarize current knowledge about the alterations of Nrf2 and Notch pathways and their reciprocal transcriptional regulation throughout tumorigenesis and progression of lung tumors, supporting the potentiality of putative biomarkers and therapeutic targets.

[Clinical Analysis of 58 Patients with Small Cell Lung Cancer Combined with Squamous Cell Cancer]

背景与目的

小细胞癌与鳞癌复合型肺癌少见，本研究分析其临床病理特征和治疗现状，探讨影响预后的因素。

方法

回顾性分析2004年1月-2012年12月58例病理细胞学证实的小细胞癌与鳞癌复合型肺癌患者的资料，采用Kaplan-Meier法计算生存率，Log-rank法进行单因素预后分析，Cox风险回归模型分析影响总生存（overall survival, OS）的因素。

结果

全组患者的OS为0.3个月-124.3个月，中位OS为22.7个月。单因素分析显示：初诊卡氏评分＜80分、广泛期、肿瘤-淋巴结-转移（tumor-node-metastasis, TNM）分期晚是影响OS的不良预后因素（P＜0.05）。多因素分析显示，只有TNM分期是独立的影响OS的因素（P=0.019）。治疗多采取化疗为主的综合模式治疗，远处转移仍是治疗失败的主要原因。

结论

小细胞癌与鳞癌复合型肺癌患者的治疗多采用以化疗为主的综合治疗模式，TNM分期是独立的预后影响因素。

Role of Adjuvant Therapy in a Population-Based Cohort of Patients With Early-Stage Small-Cell Lung Cancer

PURPOSE

Data on optimal adjuvant therapy after complete resection of small-cell lung cancer (SCLC) are limited, and in particular, there have been no studies evaluating the role of adjuvant chemotherapy, with or without prophylactic cranial irradiation, relative to no adjuvant therapy for stage T1-2N0M0 SCLC. This National Cancer Data Base analysis was performed to determine the potential benefits of adjuvant chemotherapy with and without prophylactic cranial irradiation in patients who undergo complete resection for early-stage small-cell lung cancer.

PATIENTS AND METHODS

Overall survival of patients with pathologic T1-2N0M0 SCLC who underwent complete resection in the National Cancer Data Base from 2003 to 2011, stratified by adjuvant therapy regimen, was evaluated using Kaplan-Meier and Cox proportional hazards analysis. Patients treated with induction therapy and those who died within 30 days of surgery were excluded from analysis.

RESULTS

Of 1,574 patients who had pT1-2N0M0 SCLC during the study period, 954 patients (61%) underwent complete R0 resection with a 5-year survival of 47%. Adjuvant therapy was administered to 59% of patients (n = 566), including chemotherapy alone (n = 354), chemoradiation (n = 190, including 99 patients who underwent cranial irradiation), and radiation alone (n = 22). Compared with surgery alone, adjuvant chemotherapy with or without radiation was associated with significantly improved survival. In addition, multivariable Cox modeling demonstrated that treatment with adjuvant chemotherapy (hazard ratio [HR], 0.78; 95% CI, 0.63 to 0.95) or chemotherapy with radiation directed at the brain (HR, 0.52; 95% CI, 0.36 to 0.75) was associated with improved survival when compared with no adjuvant therapy.

CONCLUSION

Patients with pT1-2N0M0 SCLC treated with surgical resection alone have worse outcomes than those who undergo resection with adjuvant chemotherapy alone or chemotherapy with cranial irradiation.

Case report: combined small cell lung cancer in a lung transplant recipient

Lung transplantation confers an increased risk of lung cancer, especially for single lung transplant recipients, due to both the epidemiologic risk factors associated with the patient population and the posttransplantation immunosuppression required. We report what we believe to be the first case of combined small cell lung carcinoma identified in the native lung of a single lung transplant recipient. Combined small cell lung cancer is an increasingly recognized subtype of small cell carcinoma, and its possible presence is an important consideration in the interpretation of fine-needle aspiration biopsies. In our case, initial fine-needle aspiration suggested squamous cell carcinoma, and it was only after lobectomy that the diagnosis of small cell carcinoma was made. The case highlights the increased risk of malignancy in lung transplant recipients and suggests a role for adaptation of lung cancer screening guidelines to address this high-risk population.

NOTCH, ASCL1, p53 and RB alterations define an alternative pathway driving neuroendocrine and small cell lung carcinomas

Small cell lung cancers (SCLCs) and extrapulmonary small cell cancers (SCCs) are very aggressive tumors arising de novo as primary small cell cancer with characteristic genetic lesions in RB1 and TP53. Based on murine models, neuroendocrine stem cells of the terminal bronchioli have been postulated as the cellular origin of primary SCLC. However, both in lung and many other organs, combined small cell/non‐small cell tumors and secondary transitions from non‐small cell carcinomas upon cancer therapy to neuroendocrine and small cell tumors occur. We define features of “small cell‐ness” based on neuroendocrine markers, characteristic RB1 and TP53 mutations and small cell morphology. Furthermore, here we identify a pathway driving the pathogenesis of secondary SCLC involving inactivating NOTCH mutations, activation of the NOTCH target ASCL1 and canonical WNT‐signaling in the context of mutual bi‐allelic RB1 and TP53 lesions. Additionaly, we explored ASCL1 dependent RB inactivation by phosphorylation, which is reversible by CDK5 inhibition. We experimentally verify the NOTCH‐ASCL1‐RB‐p53 signaling axis in vitro and validate its activation by genetic alterations in vivo. We analyzed clinical tumor samples including SCLC, SCC and pulmonary large cell neuroendocrine carcinomas and adenocarcinomas using amplicon‐based Next Generation Sequencing, immunohistochemistry and fluorescence in situ hybridization. In conclusion, we identified a novel pathway underlying rare secondary SCLC which may drive small cell carcinomas in organs other than lung, as well.

What's new?

Using next generation sequencing and establishing features of ‘small cell‐ness’, we identified a NOTCH‐ASCL1‐RB1‐TP53 signaling axis driving small cell cancers. In contrast to the previously described bi‐allelic RB1/TP53 loss in neuroendocrine stem cells as origin of primary small cell neuroendocrine cancers, the NOTCH‐ASCL1 mediated signaling defines an alternative pathway driving secondary small cell neuroendocrine cancers arising from non‐small cell cancers. Moreover, we show a preclinical rational for therapeutically testing WNT‐inhibitors in small cell cancers.

Paclitaxel-etoposide-carboplatin/cisplatin versus etoposide-carboplatin/cisplatin as first-line treatment for combined small-cell lung cancer: a retrospective analysis of 62 cases

OBJECTIVE

To compare the efficacy and adverse effects of paclitaxel-etoposide-carboplatin/cisplatin (TEP/TCE) regimen with those of etoposide-carboplatin/cisplatin (EP/CE) regimen as first-line treatment for combined small-cell lung cancer (CSCLC).

METHODS

A retrospective study was conducted on 62 CSCLC patients who were treated at Tianjin Medical University Cancer Institute and Hospital from July 2000 to April 2013 and administered with TEP/TCE regimen (n=19) or EP/CE regimen (n=43) as first-line CSCLC treatment. All patients received more than two cycles of chemotherapy, and the response was evaluated every two cycles. The primary endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and adverse effects.

RESULTS

ORR between the TEP/TCE and EP/CE groups showed a statistical difference (90% vs. 53%, P=0.033). Both groups failed to reach a statistical difference in DCR (100% vs. 86%, P=0.212). The median PFS and OS of the TEP/TCE group were slightly longer than those of the EP/CE group, although both groups failed to reach a statistical difference (10.5 vs. 8.9 months, P=0.484; 24.0 vs. 17.5 months, P=0.457). However, stratified analysis indicated that the PFS of patients with stages III and IV CSCLC showed marginally significant difference between the TEP/TCE and EP/CE groups (19.5 vs. 7.6 months; P=0.071). Both rates of grade IV bone marrow depression and termination of chemotherapy in the TEP/TCE group were significantly higher than those in the EP/CE group (26.3% vs. 7.0%, P=0.036; 31.6% vs. 14.7%, P=0.004).

CONCLUSION

The TEP/TCE regimen may not be preferred for CSCLC, and this three-drug regimen requires further exploration and research. To date, the EP/CE regimen remains the standard treatment for CSCLC patients.

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.

Paraneoplastic overlap syndrome in non-small squamous cell lung carcinoma

This is a case of paraneoplastic overlap of limbic encephalitis and opsoclonus myoclonus in a patient with non-small squamous cell lung carcinoma.

Combined small-cell lung carcinoma: An institutional experience

BACKGROUND

The purpose of this study is to determine prognostic factors and survival in patients who present with combined small-cell lung cancer (SCLC).

METHODS

A retrospective review of combined SCLC histology in patients treated between1995-2010 was undertaken. Demographics, diagnostic information, disease characteristics, treatment modality, and survival were captured. Survival estimates were performed using Kaplan Meier analysis. Statistical significance was defined as P < 0.05.

RESULTS

Forty-one patients were identified, and 35 records were available for analysis. Median age at diagnosis was 68 (range 50-85). The study included 20 (57%) women and 15 (43%) men; and 94% had a current or former history of smoking. Histology was SCLC/large cell carcinoma not otherwise specified in 28 (80%), and SCLC/adenocarcinoma or SCLC/squamous cell carcinoma in seven (20%). Cardiac or pulmonary comorbidities were present in 80% of patients, and 24 patients had metastatic disease at presentation. Twenty-eight patients received treatment of chemotherapy (n = 24), cranial radiotherapy (n = 5), or thoracic radiotherapy (n = 7). Staging was as follows: stage I-III (n = 11), stage IV (n = 24). Median survival was 15.4 months (range <1-53 months) and 3.4 months (range <1-21.9 months) for American Joint Committee on Cancer (AJCC) stage I-III and stage IV, respectively. Estimated overall six and 12 month survival was 82%, 55%, 37%, and 17% for stage I-III and stage IV, respectively. An improved overall survival rate was found for patients with an Eastern Cooperative Oncology Group performance status of <2, and no weight loss (P < 0.05).

CONCLUSION

Akin to SCLC, advanced stage combined SCLC portends a poor prognosis. Perhaps novel chemotherapeutic drugs or targeted agents may improve outcomes for future patient populations.

Serum markers in small cell lung cancer: opportunities for improvement

Lung cancer is one of the leading causes of death from malignancy worldwide. In particular small cell lung cancers, which comprise about 15-20% of all lung cancers, are extremely aggressive and cure rates are extremely low. Therefore, new treatment modalities are needed and detection at an early stage of disease, as well as adequate monitoring of treatment response is essential in order to improve outcome. In this respect, the use of non-invasive tools for screening and monitoring has gained increasing interest and the clinical applicability of reliable, tumor-related substances that can be detected as tumor markers in easily accessible body fluids is subject of intense investigation. Some of these indicators, such as high LDH levels in serum as a reflection of the disease, have been in use for a long time as a general tumor marker. To allow for improved monitoring of the efficacy of new therapeutic modalities and for accurate subtyping, there is a strong need for specific and sensitive markers that are more directly related to the biology and behavior of small cell lung cancer. In this review the current status of these potential markers, like CEA, NSE, ProGRP, CK-BB, SCC, CgA, NCAM and several cytokeratins will be critically analyzed with respect to their performance in blood based assays. Based on known cleavage sites for cytoplasmic and extracellular proteases, a prediction of stable fragments can be obtained and used for optimal test design. Furthermore, insight into the synthesis of specific splice variants and neo-epitopes resulting from protein modification and cleavage, offers further opportunities for improvement of tumor assays. Finally, we discuss the possibility that detection of SCLC related autoantibodies in paraneoplastic disease can be used as a very early indicator of SCLC.

Combined SCLC clinical and pathologic characteristics

INTRODUCTION

Despite the well characterized clinical course of 'pure' SCLC, there have not been many data on combined SCLC, ie, tumors, which contain both small-cell and non-small-cell components.

MATERIALS AND METHODS

We analyzed 1628 consecutive cases of lung cancer (1200 NSCLC, 428 SCLC) at our institution over the past decade. We identified 22 patients with C-SCLC. The pathologic and clinical characteristics of these patients were reviewed. Survival analysis was performed and prognostic factors were assessed. These data were compared with the results obtained from our 406 pure SCLC patients who presented during the same time period.

RESULTS

The most common pathology was combined small-cell and large-cell with 16 cases followed by combined small- and squamous-cell carcinoma (3 cases), 2 cases of small-cell and nonspecified NSCLC, and 1 case of small cell and adenocarcinoma. Overall survival was significantly higher in C-SCLC patients compared with pure SCLC (median 15 vs. 10.8 months; P = .035). Surgery was significantly more common in this group of patients (45% vs. 3% in the pure small cell group; P < .0001). No difference in overall survival was observed in patients with C-SCLC and patients with pure SCLC, that did not receive surgery (P = .64).

CONCLUSION

Patients with combined SCLC carry a better prognosis than those with pure small-cell variety and are more likely to undergo surgery.

[Gastrointestinal mixed adenoneuroendocrine carcinomas. An attempt at classification of mixed cancers]

Mixed adenoneuroendocrine carcinomas (MANECs) are a challenge for the diagnostics and the concept of a histogenetic tumor typing. They are classified into three malignant subgroups: high grade malignant MANECs combine an adenoma or adenocarcinoma with a small cell or large cell neuroendocrine carcinoma, intermediate grade malignant MANECs consist of a neuroendocrine tumor (NET grade 1 or 2), often a globlet cell carcinoid and a poorly differentiated adenocarcinoma or diffuse carcinoma of signet ring cell type. The prototype of a low grade malignant MANEC is the globlet cell carcinoid. Molecular analysis indicates a common clonal origin of the different components in MANECs. The prognosis is determined by the most aggressive tumor component. The pathogenesis of MANECs is apparently a sequence of increasing malignant transformation which leads either from an adenoma/adenocarcinoma to a small or large cell neuroendocrine carcinoma or from a neuroendocrine tumor (NET), often a globlet cell carcinoid to a poorly differentiated adenocarcinoma or a diffuse carcinoma of signet ring cell type.

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.

PAX5 expression in nonhematopoietic tissues. Reappraisal of previous studies

The Pax gene family encodes transcription factors with similar structures but distinctive roles in development and with limited expression in adult tissues. Reexpression of PAX proteins is frequently observed in human cancers, reflecting recapitulation of embryologic or developmental function. Defining expression of PAX family members is important in the immunohistochemical differential diagnosis of cancer, understanding oncogenesis, and defining targets for therapy. Immunostaining for PAX5 has become a commonly used technique in differential diagnosis of B-lineage hematologic malignancies. In seeking to define the range and degree of expression of PAX5 in nonhematologic pediatric cancers by immunohistochemical analysis with the anti-PAX5 monoclonal antibody routinely used in research and diagnosis, we observed strong immunostaining in a number of malignant tissues, including Wilms tumor. The pattern of expression of PAX5 in Wilms tumor was found to be identical to that of PAX2, raising the possibility of antibody cross-reactivity. This was subsequently confirmed by Western blotting and immunostaining of transfected cells and quantitative reverse transcriptase-polymerase chain reaction. Since the same PAX5 monoclonal antibody has been used consistently in the literature, these findings indicate a need for reappraisal of published PAX5 immunostaining results.