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

Advanced non-squamous NSCLC with no actionable oncogenic driver in Spain: a cross-sectional descriptive analysis of data from the Thoracic Tumor Registry

BACKGROUND

Non-small cell lung cancer (NSCLC) accounts for the vast majority of all diagnosed lung cancers. According to their histology, most NSCLCs are considered non-squamous cell carcinoma (NSCC), and up to 85% of the latter may lack either one of the two main actionable oncogenic drivers (i.e., EGFR mutations and ALK rearrangements).

OBJECTIVE

Our analysis aimed to describe the clinical and epidemiological characteristics of Spanish patients suffering from NSCC with no actionable oncogenic driver in daily clinical practice.

DESIGN

A retrospective, cross-sectional, descriptive analysis.

METHODS

We analyzed the records of all Spanish patients with advanced NSCC diagnosed between January 2011 and January 2020 and included in the Spanish Thoracic Tumor Registry database. We evaluated the presence of metastasis and molecular profiling at the time of diagnosis and treatments received. We also assessed overall survival (OS) and progression-free survival (PFS) according to first-line treatment.

RESULTS

One thousand seven hundred ninety-seven Spanish patients with NSCC were included. They were mainly men (73.2%), smokers (current [44.4%] and former [44.4%]) and presented adenocarcinoma histology (97.6%). Most patients had at least one comorbidity (80.4%) and one metastatic site (96.8%), and a non-negligible number of those tested were PD-L1 positive (35.2%). Notably, the presence of liver metastasis indicated a shorter median OS and PFS than metastasis in other locations (p < 0.001). Chemotherapy was more often prescribed than immunotherapy as first-, second-, and third-line treatment in that period. In first-line, the OS rates were similar in patients receiving either regimen, but PFS rates significantly better in patients treated with immunotherapy (p = 0.026). Also, a high number of patients did not reach second- and third-line treatment, suggesting the failure of current early diagnostic measures and therapies.

CONCLUSIONS

This analysis of the most lethal tumor in Spain could highlight the strengths and the weaknesses of its clinical management and set the ground for further advances and research.

Evolving insights into the improvement of adoptive T-cell immunotherapy through PD-1/PD-L1 blockade in the clinical spectrum of lung cancer

Undeniably, cancer immunotherapies have expanded the spectrum of cancer treatment, however, some patients do not respond to immunotherapies. This scenario is no different for lung cancer, whose two main types, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), still pose a serious clinical challenge. Adoptive T-cell therapies (ATC), which primarily include cytokine-induced killer (CIK) cell therapy, chimeric antigen receptor T-cell (CAR T-cell) therapy and γδ-T-cell therapy, strengthen the patient's immune system in combating cancer. Combining ATC with immune checkpoint inhibitors (ICI) further enhances the effectiveness of this approach to eradicate cancer. With a particular emphasis on CIK cell therapy, which recently completed 30 years, we highlight the role of the PD-1/PD-L1 axis in NSCLC and SCLC. Besides, we provide insights into the potential synergies of PD-1/PD-L1 inhibitors with adoptive T-cell immunotherapy in reshaping the treatment paradigm for lung cancer.

Efficacy and safety of anti-PD-1 inhibitor versus anti-PD-L1 inhibitor in first-line treatment of extensive-stage small cell lung cancer: a multicenter retrospective study

BACKGROUND

Immunotherapy targeting PD-1/PD-L1 has revolutionized the treatment of extensive-stage small cell lung cancer (ES-SCLC). However, clinical trials suggest differential efficacy of anti-PD-1 agents and anti-PD-L1 agents in first-line treatment of ES-SCLC. This retrospective multicenter study aimed to compare the efficacy and safety of anti-PD-1 agents versus anti-PD-L1 agents in first-line treatment of ES-SCLC in real-world practice.

METHODS

Patients with pathologically or cytologically confirmed ES-SCLC treated with platinum plus etoposide combined with anti-PD-1 or PD-L1 agents as first-line treatment in different centers of PLA General Hospital between January 2017 and October 2021 were included for this study. Survival outcomes and safety were compared between patients receiving anti-PD-1 and PD-L1 agents.

RESULTS

Of the total 154 included patients, 68 received anti-PD-1 agents plus chemotherapy (PD-1 group), and 86 received anti-PD-L1 agents plus chemotherapy (PD-L1 group). Progression-free survival (PFS) and overall survival (OS) in the entire cohort were 7.6 months (95% confidence interval [CI]: 6.5-8.2 months) and 17.4 months (95% CI: 15.3-19.3 months), respectively. Median PFS and OS were comparable between the PD-1 group and PD-L1 group (PFS: 7.6 months vs. 8.3 months, HR = 1.13, 95% CI: 0.79-1.62, p = 0.415; OS: 26.9 months vs. 25.6 months, HR = 0.96, 95% CI: 0.63-1.47, p = 0.859. The objective response rate and disease control rate were comparable between the two groups: 79.4% vs. 79.1% and 92.6% vs. 94.2%, respectively. The 6-month, 12-month, and 18-month PFS and OS rates were slightly higher in the PD-L1 group than in the PD-1 group, while the 24-month PFS rate was slightly higher in the PD-1 group than in the PD-L1 group. Stratified analysis showed that locoregional thoracic radiotherapy and normal lactate dehydrogenase level were independent predictors of better OS in ES-SCLC patients treated with first-line chemotherapy plus ICI. Adverse events were not significantly different between the two groups.

CONCLUSIONS

Anti-PD-1 agents and anti-PD-L1 agents combined with chemotherapy as first-line treatment for ES-SCLC are comparably effective and well tolerated.

Dual targeting of BCL-2 and MCL-1 in the presence of BAX breaks venetoclax resistance in human small cell lung cancer

BACKGROUND

No targeted drugs are currently available against small cell lung cancer (SCLC). BCL-2 family members are involved in apoptosis regulation and represent therapeutic targets in many malignancies.

METHODS

Expression of BCL-2 family members in 27 SCLC cell lines representing all known four SCLC molecular subtypes was assessed by qPCR, Western blot and mass spectrometry-based proteomics. BCL-2 and MCL-1 inhibition (venetoclax and S63845, respectively) was assessed by MTT assay and flow cytometry and in mice bearing human SCLC tumours. Drug interactions were calculated using the Combenefit software. Ectopic BAX overexpression was achieved by expression plasmids.

RESULTS

The highest BCL-2 expression levels were detected in ASCL1- and POU2F3-driven SCLC cells. Although sensitivity to venetoclax was reflected by BCL-2 levels, not all cell lines responded consistently despite their high BCL-2 expression. MCL-1 overexpression and low BAX levels were both characteristic for venetoclax resistance in SCLC, whereas the expression of other BCL-2 family members did not affect therapeutic efficacy. Combination of venetoclax and S63845 resulted in significant, synergistic in vitro and in vivo anti-tumour activity and apoptosis induction in double-resistant cells; however, this was seen only in a subset with detectable BAX. In non-responding cells, ectopic BAX overexpression sensitised to venetoclax and S63845 and, furthermore, induced synergistic drug interaction.

CONCLUSIONS

The current study reveals the subtype specificity of BCL-2 expression and sheds light on the mechanism of venetoclax resistance in SCLC. Additionally, we provide preclinical evidence that combined BCL-2 and MCL-1 targeting is an effective approach to overcome venetoclax resistance in high BCL-2-expressing SCLCs with intact BAX.

A review of recent advances in the novel therapeutic targets and immunotherapy for lung cancer

Lung cancer is amongst the most pervasive malignancies having high mortality rates. It is broadly grouped into non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). The concept of personalized medicine has overshadowed the conventional chemotherapy given to all patients with lung cancer. The targeted therapy is given to a particular population having specific mutations to help in the better management of lung cancer. The targeting pathways for NSCLC include the epidermal growth factor receptor, vascular endothelial growth factor receptor, MET (Mesenchymal epithelial transition factor) oncogene, Kirsten rat sarcoma viral oncogene (KRAS), and anaplastic lymphoma kinase (ALK). SCLC targeting pathway includes Poly (ADP-ribose) polymerases (PARP) inhibitors, checkpoint kinase 1 (CHK 1) pathway, WEE1 pathway, Ataxia Telangiectasia and Rad3-related (ATR)/Ataxia telangiectasia mutated (ATM), and Delta-like canonical Notch ligand 3 (DLL-Immune checkpoint inhibitors like programmed cell death protein 1 (PD-1)/ programmed death-ligand 1 (PD-L1) inhibitors and Cytotoxic T-lymphocyte-associated antigen-4 (CTLA4) blockade are also utilized in the management of lung cancer. Many of the targeted therapies are still under development and require clinical trials to establish their safety and efficacy. This review summarizes the mechanism of molecular targets and immune-mediated targets, recently approved drugs, and their clinical trials for lung cancer.

Sexual dimorphism in chronic respiratory diseases

Sex differences in susceptibility, severity, and progression are prevalent for various diseases in multiple organ systems. This phenomenon is particularly apparent in respiratory diseases. Asthma demonstrates an age-dependent pattern of sexual dimorphism. However, marked differences between males and females exist in other pervasive conditions such as chronic obstructive pulmonary disease (COPD) and lung cancer. The sex hormones estrogen and testosterone are commonly considered the primary factors causing sexual dimorphism in disease. However, how they contribute to differences in disease onset between males and females remains undefined. The sex chromosomes are an under-investigated fundamental form of sexual dimorphism. Recent studies highlight key X and Y-chromosome-linked genes that regulate vital cell processes and can contribute to disease-relevant mechanisms. This review summarises patterns of sex differences in asthma, COPD and lung cancer, highlighting physiological mechanisms causing the observed dimorphism. We also describe the role of the sex hormones and present candidate genes on the sex chromosomes as potential factors contributing to sexual dimorphism in disease.

Prognostic biomarkers and immune cell infiltration characteristics in small cell lung cancer

Background

Small cell lung cancer (SCLC) is a highly malignant and aggressive neuroendocrine tumor. With the rise of immunotherapy, it has provided a new direction for SCLC. However, due to the lack of prognostic biomarkers, the median overall survival of SCLC is still to be improved. This study aimed to explore novel biomarkers and tumor-infiltrating immune cell characteristics that may serve as potential diagnostic and prognostic markers in SCLC.

Methods

Gene expression profiles from patients with SCLC were downloaded from the Gene Expression Omnibus (GEO) database, and tumor microenvironment (TME) infiltration profile data were obtained using CIBERSORT. The robust rank aggregation (RRA) method was utilized to integrate three SCLC microarray datasets downloaded from the GEO database and identify robust differentially expressed genes (DEGs) between normal and tumor tissue samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to explore the functions of the robust DEGs. Subsequently, protein-protein interaction networks and key modules were constructed by Cytoscape, and hub genes were selected from the whole network using the plugin cytoHubba. Survival analysis of hub genes was performed by Kaplan-Meier plotter in 18 patients with extensive-stage SCLC.

Results

A total of 312 robust DEGs, including 55 upregulated and 257 downregulated genes, were screened from 129 SCLC tissue samples and 44 normal tissue samples. GO and KEGG enrichment analyses revealed that the robust DEGs were predominantly involved in human T-cell leukemia virus 1 infection, focal adhesion, complement and coagulation cascades, tumor necrosis factor (TNF) signaling pathway, and ECM-receptor interaction, which are closely associated with the development and progression of SCLC. Subsequently, three DEGs modules and six hub genes (ITGA10, DUSP12, PTGS2, FOS, TGFBR2, and ICAM1) were identified through screening with the Cytoscape plugins MCODE and cytoHubba, respectively. Immune cell infiltration analysis by the CIBERSORT algorithm revealed that resting memory CD4+ T cells were the predominant infiltrating immune cells in SCLC. In addition, Kaplan-Meier plotter revealed that the gene prostaglandin-endoperoxide synthase 2 (PTGS2) was a potential prognostic biomarker of SCLC.

Conclusions

Hub genes and tumor-infiltrating immune cells may be the molecular mechanisms underlying the development of SCLC, and this finding could contribute to the formulation of individualized immunotherapy strategies for SCLC.

The Nuclear-to-Cytoplasmic Ratio: Coupling DNA Content to Cell Size, Cell Cycle, and Biosynthetic Capacity

Though cell size varies between different cells and across species, the nuclear-to-cytoplasmic (N/C) ratio is largely maintained across species and within cell types. A cell maintains a relatively constant N/C ratio by coupling DNA content, nuclear size, and cell size. We explore how cells couple cell division and growth to DNA content. In some cases, cells use DNA as a molecular yardstick to control the availability of cell cycle regulators. In other cases, DNA sets a limit for biosynthetic capacity. Developmentally programmed variations in the N/C ratio for a given cell type suggest that a specific N/C ratio is required to respond to given physiological demands. Recent observations connecting decreased N/C ratios with cellular senescence indicate that maintaining the proper N/C ratio is essential for proper cellular functioning. Together, these findings suggest a causative, not simply correlative, role for the N/C ratio in regulating cell growth and cell cycle progression.

Cost-effectiveness analysis of adebrelimab combined with chemotherapy for extensive-stage small cell lung cancer

Background: The findings of the CAPSTONE-1 trial showed that adebrelimab in combination with chemotherapy (etoposide-carboplatin) (ADCHM) is clinically beneficial as a first-line treatment for patients with extensive-stage small cell lung cancer (ES-SCLC), compared with placebo plus chemotherapy (PLCHM, etoposide-carboplatin). However, owing to the higher cost of adebrelimab, it is unclear whether ADCHM is cost-effective compared with PLCHM. This study aimed to evaluate the cost-effectiveness of ADCHM as a first-line treatment for patients with ES-SCLC from the perspective of the Chinese healthcare system.

Methods: A Markov model with three health states was developed to assess the cost-effectiveness of ADCHM as a first-line treatment option with ES-SCLC. Clinical data were obtained from the CAPSTONE-1 trial. Costs of the drug were calculated at national tender prices, and other costs and utility values were obtained from published literature. The outcomes included life years (LYs), quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs). One-way sensitivity analysis and probabilistic sensitivity analysis were used to validate the robustness of the model.

Results: The ADCHM group achieved 1.21 QALYs (2.47 LYs) for $25,312, whereas the PLCHM group achieved 0.81 QALYs (1.59 LYs) for $14,846. The ICER for ADCHM versus PLCHM was $25914 per QALY gained. The variables with the greatest impact on the model results were the utility value of progressive disease, the utility value of progression-free survival, and the price of adebrelimab (100 mg). At a willingness-to-pay threshold of $37,653/QALY, ADCHM had an 89.1% probability of being cost-effective compared with PLCHM.

Conclusion: ADCHM may be a cost-effective first-line treatment strategy for ES-SCLC from the perspective of the Chinese healthcare system.

Real-world eligibility for platinum doublet plus immune checkpoint inhibitors in extensive-stage small-cell lung cancer

Introduction

Small cell lung cancer (SCLC) is a rapidly progressing aggressive malignancy. Durvalumab in CASPIAN and atezolizumab in IMPower133 were found to improve overall survival (OS) for extensive-stage SCLC. Here we evaluate the proportion of real-world ES SCLC patients who may be eligible for first-line immune checkpoint inhibitor (ICI) with platinum doublet.

Methods

A retrospective cohort analysis was conducted of referred ES SCLC between 2015 and 2017 in British Columbia, Canada. Patient demographics, staging, treatment, and survival data were collected through the Cancer Registry. Retrospective chart review was completed to extract past medical history and missing variables. CASPIAN/IMPower133 excluded patients with autoimmune diseases, active infection, and performance status (PS) ≥2.

Results

Between 2015 and 2017, 349 patients were diagnosed with ES SCLC. In patients who received platinum-doublet chemotherapy (n=227), 15 had medical contraindication to ICI: inflammatory bowel disease (n=4), rheumatoid arthritis (n=4), idiopathic pulmonary fibrosis (n=3), lupus (n=1), Sjogren’s (n=1), Takayasu arteritis (n=1), and active tuberculosis (n=1). ECOG PS was 0–1 in 96 (45%), PS was 2 in 61 (29%), and ≥3 in 51 (10%). Prior to cycle 1, 82 (36%) patients were eligible for ICI in addition to platinum doublet, 23% of the entire ES population. After cycles 1 and 2, additional 15 (7%) and 8 (4%) patients became PS 0–1, respectively. mOS for ES SCLC who received first-line platinum doublet, non-platinum chemotherapy, and best supportive care was 8.4 1.9 and 1.5 months (p<0.001).

Discussion

By CASPIAN/IMpower133 trial eligibility, only 36% of our real-world platinum-treated patients would have been eligible for the addition of ICI, which is 23% of the entire ES population in one Canadian province. After one or two cycles of chemotherapy, an additional 11% of patients showed PS improvement to 0–1. While the results of CASPIAN/IMpower133 are practice-changing, the majority of the patients will not meet clinical trial eligibility and clinical trials including patients with poor PS are necessary.

Small cell carcinoma of the brain without apparent extracranial origin in the same intracranial region one year following resection of malignant glioma

Primary small cell carcinoma (SCC) of the brain is rare, and there have been no reports of small cell carcinoma located at the resection site of a glioma without extracranial tumours. Herein, we report a case of brain SCC in the same intracranial region from which a malignant glioma had been surgically resected a year prior. The patient, a 68-year-old male, had headaches as a symptom, and brain CT and MRI revealed a hyperdense region measuring 5.5×5 centimetres. Blood test results showed no significant changes. H&E staining suggested that these tumour cells had the characteristics of small cell lung carcinoma cells. Immunohistochemical staining for the glioma marker S100 was negative, but immunohistochemical staining for the neuroendocrine marker synaptophysin and for the cell adhesion molecule CD56 was strongly positive; meanwhile, staining for thyroid transcription factor-1 (TTF-1), a relatively specific marker of lung and thyroid carcinoma, was positive, and the Ki67 index was 75%. The pathological examination strongly suggested that the tumour was a small cell lung carcinoma, but CT and MRI scans indicated that there were no extracranial tumours. Hence, the tumour could be a primary small cell brain carcinoma. The patient underwent surgical resection again; the excised tumour was a mass of grey and white tissues with fragmentary morphology, and its dimensions were 3.0 cm×1.5 cm×0.8 cm.

Epidemiology, treatment, and survival in small cell lung cancer in Spain: Data from the Thoracic Tumor Registry

BACKGROUND

Small-cell lung cancer (SCLC) is an aggressive disease with high metastatic potential and poor prognosis. Due to its low prevalence, epidemiological and clinical information of SCLC patients retrieved from lung cancer registries is scarce.

PATIENTS AND METHODS

This was an observational multicenter study that enrolled patients with lung cancer and thoracic tumors, recruited from August 2016 to January 2020 at 50 Spanish hospitals. Demographic and clinical data, treatment patterns and survival of SCLC patients included in the Thoracic Tumor Registry (TTR) were analyzed.

RESULTS

With a total of 956 cases, the age of 64.7 ± 9.1 years, 78.6% were men, 60.6% smokers, and ECOG PS 0, 1 or ≥ 2 in 23.1%, 53.0% and 23.8% of cases, respectively. Twenty percent of patients had brain metastases at the diagnosis. First-line chemotherapy (CT), mainly carboplatin or cisplatin plus etoposide was administered to >90% of patients. In total, 36.0% and 13.8% of patients received a second and third line of CT, respectively. Median overall survival was 9.5 months (95% CI 8.8-10.2 months), with an estimated rate of 70.3% (95% CI 67.2-73.4%), 38.9% (95% CI 35.4-42.4%), and 14.8% (95% CI 11.8-17.8%) at 6, 12 and 24 months respectively. Median progression-free survival was 6.3 months. Higher mortality and progression rates were significantly associated with male sex, older age, smoking habit, and ECOG PS 1-2. Long-term survival (> 2 years) was confirmed in 6.6% of patients, showing a positive correlation with better ECOG PS, poor smoking and absence of certain metastases at diagnosis.

CONCLUSION

This study provides an updated overview of the clinical situation and treatment landscape of ES-SCLC in Spain. Our results might assist oncologists to improve current clinical practice towards a better prognosis for these patients.

Response to first-line treatment predicts progression-free survival benefit of small-cell lung cancer patients treated with anlotinib

Background

Anlotinib significantly extended progression‐free survival (PFS) and overall survival (OS) in small‐cell lung cancer (SCLC) as third or later line treatment.

Methods

In this study, we retrospectively analyzed the efficacy and safety of anlotinib in the clinical practice and aimed to identify risk factors for predicting the clinical benefit of anlotinib in SCLC patients. 29 SCLC patients treated with anlotinib monotherapy or combination therapy as second or later line treatment were included. PFS, OS, objective response rate (ORR), disease control rate (DCR), and adverse events (AEs) were analyzed.

Results

In whole patients, the median PFS was 2.1 months (95% confidence interval (CI): 1.1–3.2 months); The ORR and DCR were 10.3% and 48.3%, respectively; The median OS was 7.2 months (95%CI: 3.2–11.2 months). Cox regression analysis demonstrated that response to first‐line treatment was the independent risk factor for PFS. The ORR (20.0% vs. 0%) and DCR (53.3% vs. 42.9%) were promoted in patients treated with anlotinib combination therapy comparing to anlotinib monotherapy. The most common AEs were hoarseness, fatigue, decreased appetite, oral mucositis, and anemia. No treatment‐related AEs graded 3 or more.

Conclusion

Anlotinib is an effective option for SCLC patients with tolerable toxicity as second or later line treatment. Patients sensitive to first‐line treatment had longer PFS when treated with anlotinib. Anloitnib combined with other therapy increased the efficacy without adding toxicity.

Molecular profiles of small cell lung cancer subtypes: therapeutic implications

Small cell lung cancer (SCLC; accounting for approximately 13%-15% of all lung cancers) is an exceptionally lethal malignancy characterized by rapid doubling time and high propensity to metastasize. In contrast to the increasingly personalized therapies in other types of lung cancer, SCLC is still regarded as a homogeneous disease and the prognosis of SCLC patients remains poor. Recently, however, substantial progress has been made in our understanding of SCLC biology. Advances in genomics and development of new preclinical models have facilitated insights into the intratumoral heterogeneity and specific genetic alterations of this disease. This worldwide resurgence of studies on SCLC has ultimately led to the development of novel subtype-specific classifications primarily based on the neuroendocrine features and distinct molecular profiles of SCLC. Importantly, these biologically distinct subtypes might define unique therapeutic vulnerabilities. Herein, we summarize the current knowledge on the molecular profiles of SCLC subtypes with a focus on their potential clinical implications.

Needle Trap Device-GC-MS for Characterization of Lung Diseases Based on Breath VOC Profiles

Volatile organic compounds (VOCs) have been assessed in breath samples as possible indicators of diseases. The present study aimed to quantify 29 VOCs (previously reported as potential biomarkers of lung diseases) in breath samples collected from controls and individuals with lung cancer, chronic obstructive pulmonary disease and asthma. Besides that, global VOC profiles were investigated. A needle trap device (NTD) was used as pre-concentration technique, associated to gas chromatography-mass spectrometry (GC-MS) analysis. Univariate and multivariate approaches were applied to assess VOC distributions according to the studied diseases. Limits of quantitation ranged from 0.003 to 6.21 ppbv and calculated relative standard deviations did not exceed 10%. At least 15 of the quantified targets presented themselves as discriminating features. A random forest (RF) method was performed in order to classify enrolled conditions according to VOCs' latent patterns, considering VOCs responses in global profiles. The developed model was based on 12 discriminating features and provided overall balanced accuracy of 85.7%. Ultimately, multinomial logistic regression (MLR) analysis was conducted using the concentration of the nine most discriminative targets (2-propanol, 3-methylpentane, (E)-ocimene, limonene, m-cymene, benzonitrile, undecane, terpineol, phenol) as input and provided an average overall accuracy of 95.5% for multiclass prediction.

History of Extensive Disease Small Cell Lung Cancer Treatment: Time to Raise the Bar? A Review of the Literature

Simple Summary

Small cell lung cancer (SCLC) remains the most aggressive form of neuroendocrine tumor of the lung, for which treatment options remain limited. The introduction of immune checkpoint inhibitors has modified for the first time the therapeutic strategies in patients with extensive disease after decades. New therapeutic approaches are required. Deeper knowledge of tumor biology is required to gain new insights into this complex disease.

Abstract

Several trials have tried for decades to improve the outcome of extensive disease small cell lung cancer (ED-SCLC) through attempts to modify the standard treatments. Nevertheless, platinum/etoposide combination and topotecan have remained respectively the first and the second line standard treatments for the last 40 years. With the advent of immunotherapy, this scenario has finally changed. Our review aims to provide an overview of the primary studies on the actual therapeutic strategies available for ED-SCLC patients, and to highlight emerging evidence supporting the use of immunotherapy in SCLC patients.

Neuron specific enolase promotes tumor metastasis by activating the Wnt/β-catenin pathway in small cell lung cancer

Neuron-specific enolase (NSE) has been used as a specific biomarker for small cell lung cancer (SCLC) patients. Nevertheless, the biological function and mechanism of NSE in SCLC are still unclear. In this study, we clarified the role of NSE in the progression of SCLC and found that NSE expression was positively correlated with distant metastasis. Functional analysis showed that overexpression of NSE promoted migration and invasion of SCLC cells. Mechanism analysis showed that NSE overexpression induced epithelial-mesenchymal transition (EMT) of SCLC cells. Moreover, overexpression of NSE increased the protein expression of β-catenin and its downstream target genes, and silencing β-catenin eliminated NSE-mediated cell migration, invasion and EMT process. Furthermore, NSE interacted with β-catenin and inhibited the degradation of β-catenin. Besides, the animal experiments also indicated that NSE could promote the EMT process and distant metastasis of SCLC cells in vivo. In summary, our results revealed that NSE could promote the EMT process of SCLC cells by activating the Wnt/β-catenin signaling pathway, thereby promoting cell migration, invasion and distant metastasis, which might serve as a potential target for the therapy of SCLC patients.

Suppression of HELLS by miR-451a represses mTOR pathway to hinder aggressiveness of SCLC

BACKGROUND

Uncovering molecular pathogenesis and mechanisms of small cell lung cancer (SCLC) will contribute to SCLC therapy. Multiple studies demonstrated that miR-451a acts as an anti-tumor miRNA in non-small cell lung cancer. However, the mechanism of miR-451a in SCLC was ambiguous.

OBJECTIVE

We aimed to explore the function of miR-451a in SCLC and decipher the underlying mechanisms.

METHODS

TargetScan and dual-luciferase reporter assays were used to analyze the target genes of miR-451a. Cell counting kit-8 and colony formation assays were performed to assess the roles of miR-451a on cell growth. Gene set enrichment analysis (GSEA) was utilized to enrich biological pathways. Western blot was used to measure protein expression.

RESULTS

MiR-451a expression was reduced dramatically in SCLC tissues and cell lines (NCI-H1688 and NCI-H446). Helicase, Lymphoid Specific (HELLS) was proved to be a target gene of miR-451a. In addition, cell proliferation assays in SCLC cells transfected with miR-451a mimic and/or HELLS revealed that miR-451a inhibited cell proliferation via targeting HELLS. Moreover, the roles of miR-451a/HELLS in expression of key proteins in mTOR and apoptosis signaling pathways suggested that miR-451a inactivated mTOR and activated apoptosis signaling pathway via directly silencing HELLS.

CONCLUSIONS

Our study indicated that miR-451a hinders SCLC cell proliferation in vitro through regulating mTOR and apoptosis signaling pathways via silencing HELLS, suggesting that miR-451a could be a promising tumor suppressor in SCLC. And there is a potential for miR-451a to be a drug target and biomarker for SCLC.

Lead DEAD/H box helicase biomarkers with the therapeutic potential identified by integrated bioinformatic approaches in lung cancer

DEAD/H box helicases are implicated in lung cancer but have not been systematically investigated for their clinical significance and function. In this study, we aimed to evaluate the potential of DEAD/H box helicases as prognostic biomarkers and therapeutic targets in lung cancer by integrated bioinformatic analysis of multivariate large-scale databases. Survival and differential expression analysis of these helicases enabled us to identify four biomarkers with the most significant alterations. These were found to be the negative prognostic factors DDX11, DDX55 and DDX56, and positive prognostic factor DDX5. Pathway enrichment analysis indicates that MYC signalling is negatively associated with expression levels of the DDX5 gene while positively associated with that of DDX11, DDX55 and DDX56. High expression levels of the DDX5 gene is associated with low mutation levels of TP53 and MUC16, the two most frequently mutated genes in lung cancer. In contrast, high expression levels of DDX11, DDX55 and DDX56 genes are associated with high levels of TP53 and MUC16 mutation. The tumour-infiltrated CD8 + T and B cells positively correlate with levels of DDX5 gene expression, while negatively correlate with that of the other three DEAD box helicases, respectively. Moreover, the DDX5-associated miRNA profile is distinguished from the miRNA profiles of DDX11, DDX55 and DDX56, although each DDX has a different miRNA signature. The identification of these four DDX helicases as biomarkers will be valuable for prognostic prediction and targeted therapeutic development in lung cancer.

Differentiating Peripherally-Located Small Cell Lung Cancer From Non-small Cell Lung Cancer Using a CT Radiomic Approach

Lung cancer can be classified into two main categories: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), which are different in treatment strategy and survival probability. The lung CT images of SCLC and NSCLC are similar such that their subtle differences are hardly visually discernible by the human eye through conventional imaging evaluation. We hypothesize that SCLC/NSCLC differentiation could be achieved via computerized image feature analysis and classification in feature space, as termed a radiomic model. The purpose of this study was to use CT radiomics to differentiate SCLC from NSCLC adenocarcinoma. Patients with primary lung cancer, either SCLC or NSCLC adenocarcinoma, were retrospectively identified. The post-diagnosis pre-treatment lung CT images were used to segment the lung cancers. Radiomic features were extracted from histogram-based statistics, textural analysis of tumor images and their wavelet transforms. A minimal-redundancy-maximal-relevance method was used for feature selection. The predictive model was constructed with a multilayer artificial neural network. The performance of the SCLC/NSCLC adenocarcinoma classifier was evaluated by the area under the receiver operating characteristic curve (AUC). Our study cohort consisted of 69 primary lung cancer patients with SCLC (n = 35; age mean ± SD = 66.91± 9.75 years), and NSCLC adenocarcinoma (n = 34; age mean ± SD = 58.55 ± 11.94 years). The SCLC group had more male patients and smokers than the NSCLC group (P < 0.05). Our SCLC/NSCLC classifier achieved an overall performance of AUC of 0.93 (95% confidence interval = [0.85, 0.97]), sensitivity = 0.85, and specificity = 0.85). Adding clinical data such as smoking history could improve the performance slightly. The top ranking radiomic features were mostly textural features. Our results showed that CT radiomics could quantitatively represent tumor heterogeneity and therefore could be used to differentiate primary lung cancer subtypes with satisfying results. CT image processing with the wavelet transformation technique enhanced the radiomic features for SCLC/NSCLC classification. Our pilot study should motivate further investigation of radiomics as a non-invasive approach for early diagnosis and treatment of lung cancer.

Prognostic value of TP53 concurrent mutations for EGFR- TKIs and ALK-TKIs based targeted therapy in advanced non-small cell lung cancer: a meta-analysis

Background

The prognostic significance of TP53 concurrent mutations in patients with epidermal growth factor receptor (EGFR)- or anaplastic lymphoma kinase (ALK)- mutated advanced non–small-cell lung cancer (NSCLC) who received EGFR-tyrosine kinase inhibitors (TKIs) or ALK-TKIs based targeted therapy remains controversial. Therefore, the present meta-analysis was performed to investigate the association between TP53 concurrent mutations and prognosis of patients with advanced NSCLC undergoing EGFR-TKIs or ALK-TKIs treatments.

Methods

Eligible studies were identified by searching the online databases PubMed, Embase, Medline, The Cochrane library and Web of Science. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to clarify the correlation between TP53 mutation status and prognosis of patients. This meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

In total, 15 studies with 1342 patients were included for final analysis. Overall, concurrent TP53 mutation was associated with unfavorable progression-free survival (PFS) (HR = 1.88, 95%CI: 1.59–2.23, p < 0.001, I² = 0.0%, P = 0.792) and overall survival (OS) (HR = 1.92, 95%CI: 1.55–2.38, p < 0.001, I² = 0.0%, P = 0.515). Subgroup analysis based on type of targeted therapy (EGFR-TKIs or ALK-TKIs, pathological type of cancer (adenocarcinoma only or all NSCLC subtypes) and line of treatment (first-line only or all lines) all showed that TP53 mutations was associated with shorter survivals of patients with EGFR-TKIs or ALK-TKIs treatments. Particularly, in patients with first-line EGFR-TKIs treatment, significantly poorer prognosis was observed in patients with TP53 concurrent mutations (pooled HR for PFS: 1.69, 95% CI 1.25–2.27, P < 0.001, I² = 0.0%, P = 0.473; pooled HR for OS: 1.94, 95% CI 1.36–2.76, P < 0.001, I² = 0.0%, P = 0.484). Begg’s funnel plots and Egger’s tests indicated no significant publication bias in this study.

Conclusions

This meta-analysis indicated that concurrent TP53 mutations was a negative prognostic factor and associated with poorer outcomes of patients with EGFR-TKIs or ALK-TKIs treatments in advanced NSCLC. In addition, our study provided evidence that TP53 mutations might be involved in primary resistance to EGFR-TKIs treatments in patients with sensitive EGFR mutations in advanced NSCLC.

A Prospective Study of Apatinib in Patients with Extensive-Stage Small Cell Lung Cancer After Failure of Two or More Lines of Chemotherapy

Background

Because of rapid disease progression and lack of optimal treatment strategies beyond the second‐line, the prognosis of patients with extensive‐stage (ES) small cell lung cancer (SCLC) still remains depressing. Alternative treatment strategies are required to improve their prognosis. In this prospective clinical study, we aimed to evaluate the feasibility of single‐agent apatinib, a vascular endothelial growth factor receptor‐2 tyrosine kinase inhibitor, as a treatment option for patients with ES‐SCLC after failure of at least two prior chemotherapy regimens.

Materials and Methods

Twenty‐two patients with ES‐SCLC treated with 500 mg single‐agent apatinib as subsequent‐line regimen in our institution from November 2016 to August 2018 were enrolled in the study. The primary endpoint was progression‐free survival (PFS). The secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), and adverse events (AEs).

Results

Clinical outcomes included partial response in 3 patients (13.6%), stable disease in 18 patients (81.8%), and disease progression in 1 patient (4.5%), with an ORR of 13.6% and DCR of 95.5%. The median PFS and OS were 5.4 and 10.0 months, respectively. Apatinib demonstrated a manageable toxicity profile, with grade I–III secondary hypertension and proteinuria as the most common AEs. No grade IV and V AEs were observed among the patients. Multivariate analysis revealed secondary hypertension as an independent predictor of OS (p = .047); however, the association became insignificant after Q correction (p = .455).

Conclusions

Apatinib was safe and effective in the management of patients with ES‐SCLC and can be considered as a treatment option after failure of at least two prior chemotherapy regimens. http://ClinicalTrials.govidentifier. NCT02995187

Implications for Practice

This study indicated the acceptable toxicity profile and promising efficacy of apatinib in the management of patients with extensive‐stage small cell lung cancer after failure from at least two prior chemotherapy regimens. Secondary hypertension can be a potential prognostic factor for apatinib treatment.

Alternative treatment strategies are needed to improve prognosis for patients with small‐cell lung cancer. This article evaluates the feasibility of single‐agent apatinib as a treatment option for patients with extensive‐stage small‐cell lung cancer.

Prevalence of DLL3, CTLA-4 and MSTN Expression in Patients with Small Cell Lung Cancer

Introduction

Immune-based and antibody-drug conjugate therapies have shown promise in the treatment of patients with small cell lung cancer (SCLC). However, better predictive biomarkers are needed for selection of the appropriate SCLC patients for these advanced therapies and also for evaluation of the efficacy of these treatments.

Objective

The aim of this study was to examine the expression of delta-like protein 3 (DLL3), cytotoxic T lymphocyte-associated protein 4 (CTLA-4), and mesothelin (MSTN) in patients with SCLC and compare them with those patients’ clinical characteristics.

Methods

Immunohistochemical analyses of DLL3, CTLA-4 and MSTN expression were performed in 38 samples from patients with SCLC.

Results

We found that positive expression in patients of the biomarkers was as follows: for DLL3, 100% (38/38), for CTLA-4, 89.5% (36/38) and for MSTN 81.5% (31/38). The median survival time was 17.9 months in the DLL3 high expression group and 23 months in the DLL3 low expression group. Patients with a high expression of DLL3 showed a poorer prognosis than those with a low expression of DLL3 (HR=3.4; 95% CI, 1.34–8.6; p=0.01).

Conclusion

The expression of DLL3, CTLA-4 and MSTN was not correlated with patients’ age, sex, smoking status, stage, and tumor metastasis. The fact that there was a higher expression of DLL3, CTLA-4, and MSTN in SCLC suggested that these molecules could be used as predictive biomarkers for SCLC.

Effects of salinomycin and niclosamide on small cell lung cancer and small cell lung cancer circulating tumor cell lines

Tumor dissemination and recurrence is attributed to highly resistant cancer stem cells (CSCs) which may constitute a fraction of circulating tumor cells (CTCs). Small cell lung cancer (SCLC) constitutes a suitable model to investigate the relation of CTCs and CSCs due to rapid tumor spread and a high number of CTCs. Expansion of five SCLC CTC lines (BHGc7, 10, 16, 26 and UHGc5) in vitro at our institution allowed for the analysis of CSC markers and cytotoxicity of the CSC-selective drugs salinomycin and niclosamide against CTC single cell suspensions or CTC spheroids/ tumorospheres (TOS). Salinomycin exerted dose-dependent cytotoxicity against the SCLC lines but, with exception of BHGc7 TOS, there was no markedly enhanced activity against TOS. Similarly, niclosamide exhibits high activity against BHGc7 TOS and UHGc5 TOS but not against the other CTC spheroids. High expression of the CSC marker CD133 was restricted to three SCLC tumor lines and the BHGc10 CTC line. All SCLC CTCs are CD24-positive but lack expression of CD44 and ABCG2 in contrast to the SCLC tumor lines which show a phenotype more similar to that of CSCs. The stem cell marker SOX2 was found in all CTC lines and SCLC GLC14/16, whereas elevated expression of Oct-3/4 and Nanog was restricted to BHGc26 and UHGc5. In conclusion, the SCLC CTCs established from patients with relapsed disease lack a typical CSC phenotype in respect to chemosensitivity to CSC-selective drugs, surface markers, expression of pluripotent stem cell and transcription factors.

Soluble fms-like tyrosine kinase-1-enriched exosomes suppress the growth of small cell lung cancer by inhibiting endothelial cell migration

Background

Previous studies have reported that soluble fms‐like tyrosine kinase‐1 (sFlt‐1) possesses anti‐tumor effects by inhibiting angiogenesis in many cancers. Exosomes can be engineered as delivery vehicles for transferring functional biomolecules, such as proteins, lipids, and nucleic acids (DNA, mRNA, and miRNA) to target cells to affect inflammation, apoptosis, and angiogenesis. The purpose of this study was to investigate whether exosomes can function as efficient carriers of sFlt‐1 in vitro and in vivo, to play a role in SCLC therapy.

Methods

We adopted three different methods: TEM, NTA and western blot analysis to characterize the cell‐derived exosomes from NCI‐H69 SCLC cell line and normal bronchial epithelial BEAS‐2B cell line. we next explored the effects of these exosomes on HUVE cell proliferation and migration in vitro.To verify sFlt‐1‐loaded exosomes suppress the tumor growth in vivo,we established subcutaneous xenografts in nude mice using the NCI‐H69 cell line.

Results

We observed that NCI‐H69‐exo significantly increased human umbilical vein endothelial cells (HUVEC) migration compared to BEAS‐2B‐exo in vitro and in vivo. sFlt‐1 protein expression was statistically higher in BEAS‐2B‐exo than NCI‐H69‐exo. sFlt‐1 protein or sFlt‐1‐enriched exosomes can inhibit the migration of HUVECs. Furthermore, sFlt‐1‐enriched exosomes exhibited higher inhibition efficacy on pro‐angiogenesis of NCI‐H69‐exo in comparison with the same concentration of sFlt‐1 protein. Intriguingly, sFlt‐1‐loaded exosomes showed marked anti‐tumor activity by inhibiting the growth of NCI‐H69 tumor xenografts. CD31 staining revealed that sFlt‐1‐loaded exosomes significantly reduced the vascular density of experimental mice. sFlt‐1‐loaded exosomes markedly induced tumor apoptosis and inhibited tumor cell proliferation in mice.

Conclusion

Exosomes from a SCLC cell line contain low levels of sFlt‐1 and significantly increased the migration of HUVECs. SFlt‐1‐enriched exosomes can inhibit NCI‐H69‐exo‐induced HUVEC migration. Exosomes enriched in sFlt‐1 have the potential to be effective therapeutic agents for SCLC.

Identification of candidate genes associated with the pathogenesis of small cell lung cancer via integrated bioinformatics analysis

The pathogenesis of small cell lung cancer (SCLC), a highly metastatic malignant tumor, remains unclear. In the present study, important genes and pathways that are involved in the pathogenesis of SCLC were identified. The following four datasets were downloaded from the Gene Expression Omnibus: GSE60052, GSE43346, GSE15240 and GSE6044. The differentially expressed genes (DEGs) between the SCLC samples and the normal samples were analyzed using R software. The limma package was used for every dataset. The RobustRankAggreg package was used to integrate the DEGs from the four datasets. Functional and pathway enrichment analyses were conducted using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases with FunRich software and R software, respectively. In addition, the protein-protein interaction (PPI) network of the DEGs was constructed using the STRING database and Cytoscape software. Hub genes and significant modules were identified using Molecular Complex Detection in Cytoscape software. Finally, the expression values of hub genes were determined using the Oncomine online database. In total, 412 DEGs were identified following the integration of the four datasets, with 146 upregulated genes and 266 downregulated genes. The upregulated DEGs were primarily enriched in the cell cycle, cell division and microtubule binding. The downregulated DEGs were primarily enriched in the complement and coagulation cascades, the cytokine-mediated signaling pathway and protein binding. Eight hub genes and 1 significant module correlated to the cell cycle pathway were identified based on a subset of the PPI network. Finally, five hub genes were identified as highly expressed in SCLC tissue compared with normal tissue. The cell cycle pathway may be the pathway most closely associated with the pathogenesis of SCLC. NDC80, BUB1B, PLK1, CDC20 and MAD2L1 should be the focus of follow-up studies regarding the diagnosis and treatment of SCLC.

Bioinformatics analysis of mRNA and miRNA microarray to identify the key miRNA‑gene pairs in small‑cell lung cancer

Small-cell lung cancer (SCLC) is a type of lung cancer with early metastasis, and high recurrence and mortality rates. The molecular mechanism is still unclear and further research is required. The aim of the present study was to examine the pathogenesis and potential molecular markers of SCLC by comparing the differential expression of mRNA and microRNA (miRNA) between SCLC tissue and normal lung tissue. A transcriptome sequencing dataset (GSE6044) and a non-coding RNA sequence dataset (GSE19945) were downloaded from the Gene Expression Omnibus (GEO) database. In total, 451 differentially expressed genes (DEGs) and 134 differentially expressed miRNAs (DEMs) were identified using the R limma software package and the GEO2R tool of the GEO, respectively. The Gene Ontology function was significantly enriched for 28 terms, and the Kyoto Encyclopedia of Genes and Genomes database had 19 enrichment pathways, mainly related to ‘cell cycle’, ‘DNA replication’ and ‘oocyte meiosis mismatch repair’. The protein-protein interaction network was constructed using Cytoscape software to identify the molecular mechanisms of key signaling pathways and cellular activities in SCLC. The 1,402 miRNA-gene pairs encompassed 602 target genes of the DEMs using miRNAWalk, which is a bioinformatics platform that predicts DEM target genes and miRNA-gene pairs. There were 19 overlapping genes regulated by 32 miRNAs between target genes of the DEMs and DEGs. Bioinformatics analysis may help to better understand the role of DEGs, DEMs and miRNA-gene pairs in cell proliferation and signal transduction. The related hub genes may be used as biomarkers for the diagnosis and prognosis of SCLC, and as potential drug targets.

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

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

Dynamics of multiple resistance mechanisms in plasma DNA during EGFR-targeted therapies in non-small cell lung cancer

Tumour heterogeneity leads to the development of multiple resistance mechanisms during targeted therapies. Identifying the dominant driver(s) is critical for treatment decision. We studied the relative dynamics of multiple oncogenic drivers in longitudinal plasma of 50 EGFR-mutant non-small-cell lung cancer patients receiving gefitinib and hydroxychloroquine. We performed digital PCR and targeted sequencing on samples from all patients and shallow whole-genome sequencing on samples from three patients who underwent histological transformation to small-cell lung cancer. In 43 patients with known EGFR mutations from tumour, we identified them accurately in plasma of 41 patients (95%, 41/43). We also found additional mutations, including EGFR T790M (31/50, 62%), TP53 (23/50, 46%), PIK3CA (7/50, 14%) and PTEN (4/50, 8%). Patients with both TP53 and EGFR mutations before treatment had worse overall survival than those with only EGFR Patients who progressed without T790M had worse PFS during TKI continuation and developed alternative alterations, including small-cell lung cancer-associated copy number changes and TP53 mutations, that tracked subsequent treatment responses. Longitudinal plasma analysis can help identify dominant resistance mechanisms, including non-druggable genetic information that may guide clinical management.

Identification of candidate biomarkers and pathways associated with SCLC by bioinformatics analysis

Small cell lung cancer (SCLC) is one of the highly malignant tumors and a serious threat to human health. The aim of the present study was to explore the underlying molecular mechanisms of SCLC. mRNA microarray datasets GSE6044 and GSE11969 were downloaded from Gene Expression Omnibus database, and the differentially expressed genes (DEGs) between normal lung and SCLC samples were screened using GEO2R tool. Functional and pathway enrichment analyses were performed for common DEGs using the DAVID database, and the protein-protein interaction (PPI) network of common DEGs was constructed by the STRING database and visualized with Cytoscape software. In addition, the hub genes in the network and module analysis of the PPI network were performed using CentiScaPe and plugin Molecular Complex Detection. Finally, the mRNA expression levels of hub genes were validated in the Oncomine database. A total of 150 common DEGs with absolute fold-change >0.5, including 66 significantly downregulated DEGs and 84 upregulated DEGs were obtained. The Gene Ontology term enrichment analysis suggested that common upregulated DEGs were primarily enriched in biological processes (BPs), including ‘cell cycle’, ‘cell cycle phase’, ‘M phase’, ‘cell cycle process’ and ‘DNA metabolic process’. The common downregulated genes were significantly enriched in BPs, including ‘response to wounding’, ‘positive regulation of immune system process’, ‘immune response’, ‘acute inflammatory response’ and ‘inflammatory response’. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified that the common downregulated DEGs were primarily enriched in the ‘complement and coagulation cascades’ signaling pathway; the common upregulated DEGs were mainly enriched in ‘cell cycle’, ‘DNA replication’, ‘oocyte meiosis’ and the ‘mismatch repair’ signaling pathways. From the PPI network, the top 10 hub genes in SCLC were selected, including topoisomerase IIα, proliferating cell nuclear antigen, replication factor C subunit 4, checkpoint kinase 1, thymidylate synthase, minichromosome maintenance protein (MCM) 2, cell division cycle (CDC) 20, cyclin dependent kinase inhibitor 3, MCM3 and CDC6, the mRNA levels of which are upregulated in Oncomine SCLC datasets with the exception of MCM2. Furthermore, the genes in the significant module were enriched in ‘cell cycle’, ‘DNA replication’ and ‘oocyte meiosis’ signaling pathways. Therefore, the present study can shed new light on the understanding of molecular mechanisms of SCLC and may provide molecular targets and diagnostic biomarkers for the treatment and early diagnosis of SCLC.

Advanced small cell lung cancer (SCLC): new challenges and new expectations

Small cell lung cancer (SCLC) remains one of the most lethal malignancies and a major health riddle. The therapeutic options are limited. The combination of etoposide or irinotecan with platinum chemotherapy is the standard of care at any stage. The last decade systemic efforts have been done to reveal specific therapeutic targets for small cell lung carcinomas. In this review, we focus on the new therapeutic strategies of SCLC, including immune-related treatment that may change the prognosis of the disease. The main genetic mutations observed in SCLC are TP53 and RB1 mutations; however, it is well known that these molecules are not yet targetable. In recent years, research has revealed other frequent genetic alterations and activated signaling pathways that might be an effective treatment target. Loss of PTEN, activating PI3K mutations, inhibition of NOTCH pathway and aurora kinase activation are among them. Moreover, FDGFR1 amplification, activation of the Hedgehog pathway and repair-protein PARP1 seem to participate in SCLC tumorigenesis. These new findings have identified some interesting targets. Moreover, immunotherapy tries to find its place in the treatment of SCLC. Immune checkpoint inhibitors are under investigation in phase I to III clinical trials. We hope that in next years the treatment of SCLC patients will be improved with the administration of targeting therapy and the introduction of immunotherapy.

Progress and prospects of early detection in lung cancer

Lung cancer is the leading cause of cancer-related death in the world. It is broadly divided into small cell (SCLC, approx. 15% cases) and non-small cell lung cancer (NSCLC, approx. 85% cases). The main histological subtypes of NSCLC are adenocarcinoma and squamous cell carcinoma, with the presence of specific DNA mutations allowing further molecular stratification. If identified at an early stage, surgical resection of NSCLC offers a favourable prognosis, with published case series reporting 5-year survival rates of up to 70% for small, localized tumours (stage I). However, most patients (approx. 75%) have advanced disease at the time of diagnosis (stage III/IV) and despite significant developments in the oncological management of late stage lung cancer over recent years, survival remains poor. In 2014, the UK Office for National Statistics reported that patients diagnosed with distant metastatic disease (stage IV) had a 1-year survival rate of just 15-19% compared with 81-85% for stage I.

Is neuron-specific enolase useful for diagnosing malignant pleural effusions? evidence from a validation study and meta-analysis

Background

Neuron-Specific enolase (NSE) has been used as a typical tumor marker and shows a potential to diagnose malignant pleural effusion (MPE). The ability of NSE in diagnosing MPE has been investigated in many studies, but with inconsistent conclusions. This study sought to investigate the diagnostic accuracy of NSE for MPE through a clinical study and together with a meta-analysis.

Methods

Pleural effusion samples from 136 patients with MPE and 102 patients with benign pleural effusion (BPE) were collected, and NSE levels were measured by electrochemiluminescence immunoassay. Receiver operating characteristic (ROC) curve analysis was performed to assess the ability of NSE to differentiate MPE from BPE. Literature search was conducted to identify suitable publications, data were extracted and diagnostic indexes including sensitivity, specificity, positive/negative likelihood ratio (PLR/NLR), and diagnostic odds ratio (DOR) were pooled. Summary ROC curve was generated to determine the overall diagnostic accuracy of NSE for MPE.

Results

Levels of NSE were significantly increased in pleural effusion from patients with MPE than that from BPE (18.53 ± 27.30 vs. 6.41 ± 6.95 ng/ml, p < 0.001). With a cut-off value of 8.92 ng/ml, pleural NSE had a sensitivity of 59.56% and a specificity of 83.33% in diagnosing MPE. A total of 14 studies with 1896 subjects were included for meta-analysis. The diagnostic parameters of NSE were listed as follows: sensitivity, 0.53 (95% CI: 0.38–0.67); specificity, 0.85 (95% CI: 0.75–0.91); PLR, 3.54 (95% CI: 2.33–5.39); NLR, 0.56 (95% CI: 0.42–0.73); and DOR, 6.39 (95% CI: 3.72–10.96). The area under the summary ROC curve was 0.78.

Conclusions

The role of pleural NSE measurement in diagnosing MPE is limited and with a low sensitivity. The clinical utility of NSE assay should be combined with the results of other tumor markers examination and the detail clinical information of patient. Further studies are needed to confirm the role of NSE in diagnosing MPE.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3572-2) contains supplementary material, which is available to authorized users.

Significantly mutated genes and regulatory pathways in SCLC-a meta-analysis

Small cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers and demands effective targeted therapeutic strategies. In this meta-analysis study, we aim to identify significantly mutated genes and regulatory pathways to help us better understand the progression of SCLC and to identify potential biomarkers. Besides ranking genes based on their mutation frequencies, we sought to identify statistically significant mutations in SCLC with the MutSigCV software. Our analysis identified several genes with relatively low mutation frequency, including PTEN, as highly significant (p < 0.001), suggesting these genes may play an important role in the progression of SCLC. Our results also indicated mutations in genes involved in the axon guidance pathways likely play an important role in SCLC progression. In addition, we observed that the mutation rate was significantly higher in samples with RB1 gene mutated when compared to samples with wild type RB1, suggesting that RB1 status has significant impact on the mutation profile and disease progression in SCLC.

A prospective pilot study of genome-wide exome and transcriptome profiling in patients with small cell lung cancer progressing after first-line therapy

Background

Small cell lung cancer (SCLC) that has progressed after first-line therapy is an aggressive disease with few effective therapeutic strategies. In this prospective study, we employed next-generation sequencing (NGS) to identify therapeutically actionable alterations to guide treatment for advanced SCLC patients.

Methods

Twelve patients with SCLC were enrolled after failing platinum-based chemotherapy. Following informed consent, genome-wide exome and RNA-sequencing was performed in a CLIA-certified, CAP-accredited environment. Actionable targets were identified and therapeutic recommendations made from a pharmacopeia of FDA-approved drugs. Clinical response to genomically-guided treatment was evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1.

Results

The study completed its accrual goal of 12 evaluable patients. The minimum tumor content for successful NGS was 20%, with a median turnaround time from sample collection to genomics-based treatment recommendation of 27 days. At least two clinically actionable targets were identified in each patient, and six patients (50%) received treatment identified by NGS. Two had partial responses by RECIST 1.1 on a clinical trial involving a PD-1 inhibitor + irinotecan (indicated by MLH1 alteration). The remaining patients had clinical deterioration before NGS recommended therapy could be initiated.

Conclusions

Comprehensive genomic profiling using NGS identified clinically-actionable alterations in SCLC patients who progressed on initial therapy. Recommended PD-1 therapy generated partial responses in two patients. Earlier access to NGS guided therapy, along with improved understanding of those SCLC patients likely to respond to immune-based therapies, should help to extend survival in these cases with poor outcomes.

Histopathological transformation to small-cell lung carcinoma in non-small cell lung carcinoma tumors

Lung cancer is the principal cause of cancer-related death worldwide. The use of targeted therapies, especially tyrosine kinase inhibitors (TKIs), in specific groups of patients has dramatically improved the prognosis of this disease, although inevitably some patients will develop resistance to these drugs during active treatment. The most common cancer-associated acquired mutation is the epidermal growth factor receptor (EGFR) Thr790Met (T790M) mutation. During active treatment with targeted therapies, histopathological transformation to small-cell lung carcinoma (SCLC) can occur in 3-15% of patients with non-small-cell lung carcinoma (NSCLC) tumors. By definition, SCLC is a high-grade tumor with specific histological and genetic characteristics. In the majority of cases, a good-quality hematoxylin and eosin (H&E) stain is enough to establish a diagnosis. Immunohistochemistry (IHC) is used to confirm the diagnosis and exclude other neoplasia such as sarcomatoid carcinomas, large-cell carcinoma, basaloid squamous-cell carcinoma, chronic inflammation, malignant melanoma, metastatic carcinoma, sarcoma, and lymphoma. A loss of the tumor-suppressor protein retinoblastoma 1 (RB1) is found in 100% of human SCLC tumors; therefore, it has an essential role in tumorigenesis and tumor development. Other genetic pathways probably involved in the histopathological transformation include neurogenic locus notch homolog (NOTCH) and achaete-scute homolog 1 (ASCL1). Histological transformation to SCLC can be suspected in NSCLC patients who clinically deteriorate during active treatment. Biopsy of any new lesion in this clinical setting is highly recommended to rule out a SCLC transformation. New studies are trying to assess this histological transformation by noninvasive measures such as measuring the concentration of serum neuron-specific enolase.