Molecular profiles of small cell lung cancer subtypes: therapeutic implications

Liquid biopsy in diagnosis and monitoring of treatment efficacy in patients with small cell lung cancer

Small-cell lung cancer (SCLC) remains one of the deadliest cancers worldwide. Patients' survival remains poor due to its rapid growth, high metastatic rate and limited possibilities of treatment. For many years, SCLC management has been based mostly on chemo and radiotherapy. However, new therapeutic approaches have been proposed in the past few years, including immunotherapy, which is currently implemented in clinical practice. Unfortunately, in many cases, response to therapy, especially chemotherapy, remains poor, or the patient becomes resistant to initially effective treatment. One of the crucial problems during SCLC patient care is a lack of appropriate predictive biomarkers for various therapeutic approaches. Another critical issue is the scarcity of collected tissue during biopsy, which may be insufficient or of too poor quality for analysis. A liquid biopsy might be the key to solving both of those problems as it is collected in a non-invasive way and enables the measurement of various biomarkers, including circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs). In this review, we discuss various approaches to potentially incorporating liquid biopsy into clinical application - as a companion to imaging during SCLC diagnostics, a new approach to molecular subtyping, and a material enabling predictive or prognostic biomarkers assessment. We also summarize ongoing clinical trials encompassing SCLC patients in which liquid biopsy is collected and examined.

Histology-Specific Treatment Strategies and Survival Prediction in Lung Cancer Patients with Spinal Metastases: A Nationwide Analysis

BACKGROUND/OBJECTIVES

Spinal metastases are a common and severe complication of lung cancer, particularly in small cell lung cancer (SCLC), and are associated with poor survival. Despite advancements in treatment, optimal management strategies remain unclear, with significant differences between non-small cell lung cancer (NSCLC) and SCLC. This study evaluates treatment patterns, survival outcomes, and prognostic factors in lung cancer patients with spinal metastases, integrating deep learning survival prediction models.

METHODS

This retrospective cohort study analyzed the National Cancer Database (NCDB) to identify NSCLC and SCLC patients diagnosed with spinal metastases. Demographics and treatment modalities were analyzed and adjusted for age, sex, and comorbidities. Kaplan-Meier analysis and Cox proportional hazards models assessed overall survival (OS). Five advanced survival prediction models estimated 1-year and 10-year mortality, with feature importance determined via permutation analysis.

RESULTS

Among 428,919 lung cancer patients, 5.1% developed spinal metastases, with a significantly higher incidence in SCLC (13.6%) than in NSCLC (5.1%). SCLC patients had poorer OS. Radiation therapy alone was the predominant treatment, and stereotactic body radiation therapy (SBRT) predicted better short- and long-term survival compared to other radiation techniques. High-dose radiation (71-150 Gy BED) improved OS in NSCLC, while reirradiation benefited NSCLC but had a limited impact in SCLC. SurvTrace demonstrated the highest predictive accuracy for 1-year and 10-year mortality, identifying age, radiation dose, reirradiation, and race as key prognostic factors.

CONCLUSIONS

The management of spinal metastases requires a histology-specific approach. Radiation remains the primary treatment, with SBRT predicting better short- and long-term survival. High-dose radiation and reirradiation should be considered for NSCLC, while the benefits are limited in SCLC. These findings support histology-specific treatment strategies to improve survival of patients with metastatic lung cancer to the spine.

Comparative profiling of surgically resected primary tumors and their lymph node metastases in small-cell lung cancer

BACKGROUND

Profiling studies in small-cell lung cancer (SCLC) have mainly focused on primary tumors, omitting the potential molecular changes that might occur during lymphatic metastasis formation. Here, we assessed the molecular discordance between primary SCLCs and corresponding lymph node (LN) metastases in the light of subtype distribution and expression of clinically relevant proteins.

METHODS

Comparative profiling of 32 surgically resected primary SCLCs and their LN metastases was achieved by RNA expression analysis and immunohistochemistry (IHC). In addition to subtype markers (ASCL1, NEUROD1, POU2F3, and YAP1), the expression of nine cancer-specific proteins was evaluated.

RESULTS

The selected clinically relevant molecules showed no significant differences in their RNA expression profile when assessing the primary tumors and their corresponding LN metastases. Nevertheless, IHC analyses revealed significantly higher DLL3 expression in the primary tumors than in the LN metastases (P = 0.008). In contrast, NEUROD1 expression was significantly lower in the primary tumors (versus LN metastases, P < 0.001). No statistically significant difference was found by IHC analysis in the case of other clinically relevant proteins. Concerning SCLC molecular subtypes, a change in subtype distribution was detected in 21 cases. Phenotype switching from neuroendocrine (NE) subtypes toward non-NE lesions and from non-NE landscape toward NE subtypes were both detected.

CONCLUSIONS

Although the molecular landscape of SCLC LN metastases largely resembles that of the tumor of origin, key differences exist in terms of DLL3 and NEUROD1 expression, and in subtype distribution. These diagnostic pitfalls should be considered when establishing the tumors' molecular profile for future clinical trials solely based on LN biopsies.

Exploring resistance to initial chemotherapy in small cell lung cancer: The role of bone metastasis and other clinicopathologic characteristics

Clinically, approximately 10% to 20% of small cell lung cancer (SCLC) patients do not respond well to initial platinum-based first-line chemotherapy. Knowledge about the clinicopathologic characteristics of these primary drug-resistant populations is limited. This study aimed to explore the clinicopathologic characteristics in SCLC populations insensitive to initial chemotherapy. This study enrolled SCLC patients with insensitivity to initial chemotherapy and analyzed their clinicopathological characteristics. Binary logistic regression analysis was used to determine the independent factors that influence chemosensitivity. The study evaluated 142 cases to determine the clinicopathologic characteristics of SCLC populations with insensitivity to initial chemotherapy. Between the chemotherapy-insensitive group (n = 32) and the chemotherapy-sensitive group (n = 110), no significant differences were observed in sex, age, smoking status, tumor size, lymph-node metastasis, vascular invasion, carcinomatous lymphangitis, mediastinal invasion, superior vena cava syndrome, tumor stage, brain metastases, pleural metastasis, lung metastasis, adrenal metastasis, or the immunohistochemical markers cytokeratin, synaptophysin, chromogranin A, thyroid transcription factor-1, and Ki-67 (all P > .05). However, significant differences in liver metastasis (P = .005), bone metastasis (P < .001), and neural cell adhesion molecule expression (P = .027) were identified. Binary logistic regression analysis revealed that bone metastasis (P = .008) was an independent high-risk factor for insensitivity to initial first-line chemotherapy. Bone metastasis is an independent high-risk factor for insensitivity to initial chemotherapy in SCLC. Enhancing our understanding of SCLC biology and osteoimmuno-oncology could identify new vulnerabilities and better define patient populations that may benefit from tailored clinical treatments to overcome drug resistance.

Tislelizumab-induced type 1 diabetic ketoacidosis in a patient with small cell lung cancer: a case report

This report presented a case of 71-year-old man diagnosed with extensive-stage small cell lung cancer (ES-SCLC) who developed type 1 diabetic ketoacidosis (DKA) after 3 cycles of tislelizumab plus chemotherapy for the first time. The patient had no history of diabetes mellitus (DM). According to medical history and laboratory examination, the case was definitely diagnosed new-onset type 1 diabetic ketoacidosis induced by tislelizumab, a kind of immune checkpoint inhibitor. Despite the incidence of immune checkpoint inhibitor-induced type 1 diabetes mellitus (ICI-T1DM) is rare, the development of ICI-T1DM, especially type 1 diabetic ketoacidosis is life-threating without blood glucose monitoring and insulin therapy. Early identification of hyperglycemia and C-peptide depletion, as well as routine blood glucose monitoring during ICI treatment is essential to avoid lethal endocrine immune-related adverse event (irAE).

Cost-effectiveness analysis of trilaciclib for preventing myelosuppression in small cell lung cancer patients treated with etoposide, carboplatin, and atezolizumab

This study evaluated the economic value of administering trilaciclib to prevent myelosuppression in extensive-stage small cell lung cancer (ES-SCLC) patients receiving etoposide, carboplatin, and atezolizumab (E/P/A) from both the Chinese and the United States (US) perspectives. A decision tree model was constructed to estimate and compare costs, quality-adjusted life years (QALYs), incremental cost-effectiveness ratios (ICERs), incremental net health benefits (INHBs), and incremental net monetary benefits (INMBs). One-way and probabilistic sensitivity analyses were conducted to assess the robustness and uncertainty of the economic analysis. The base case analysis indicated that from the perspective of US payers, trilaciclib was cost-saving at the WTP threshold of $241,230.00, with an incremental cost of $-12,626.08, an INMB of $16,788.02, and an INHB of 0.07 QALYs. Conversely, from the perspective of Chinese payers, the use of trilaciclib was not economical at the WTP threshold of $35,817.44, with an ICER of $691,541.63/QALY, an INMB of -$8,765.52, and an INHB of -0.24 QALYs. Sensitivity analysis confirmed the stability of these results. Probabilistic sensitivity analysis indicated that, from the Chinese payers' perspective, trilaciclib treatment was not economical, with a probability of 100%. In contrast, from the US payers' perspective, it was economical, with a probability of 90.05%. Given the limited clinical data available for trilaciclib in the Chinese population, the cost-effectiveness of trilaciclib may improve with the inclusion of new data or changes in health insurance policies.

Proceedings of the 1st biannual bridging the gaps in lung cancer conference

Lung cancer is the leading cause of cancer death in the US and globally. The mortality from lung cancer has been declining, due to a reduction in incidence and advances in treatment. Although recent success in developing targeted and immunotherapies for lung cancer has benefitted patients, it has also expanded the complexity of potential treatment options for health care providers. To aid in reducing such complexity, experts in oncology convened a conference (Bridging the Gaps in Lung Cancer) to identify current knowledge gaps and controversies in the diagnosis, treatment, and outcomes of various lung cancer scenarios, as described here. Such scenarios relate to biomarkers and testing in lung cancer, small cell lung cancer, EGFR mutations and targeted therapy in non-small cell lung cancer (NSCLC), early-stage NSCLC, KRAS/BRAF/MET and other genomic alterations in NSCLC, and immunotherapy in advanced NSCLC.

Comprehensive Characterization via Molecular Imaging, Longitudinal Multisite Sampling, and Autoptic Work-up in Advanced Small Cell Lung Cancer Undergoing SSTR-Directed Radiopharmaceutical Therapy

Despite the addition of immune checkpoint blockade to first-line chemotherapy, the prognosis for patients with small cell lung cancer (SCLC) is still devastating. For the subset of SCLC with somatostatin receptor (SSTR) overexpression, radiopharmaceutical therapy (RPT) might be an effective future treatment option. Methods: Here, we present the case of a heavily pretreated stage IV SCLC patient showing an exceptional response to SSTR-directed RPT. A comprehensive translational work-up consisting of histopathologic, immunohistochemical, and molecular pathology analyses at different time points during treatment and especially of lesions with discordant tracer uptake was performed. Results: Besides a promising response to RPT, interesting signs of clonal dynamics under therapy and, most importantly, SSTR downregulation of some lesions as a potential evasion mechanism to SSTR-directed RPT could be identified. Conclusion: This unique investigation for a clinical-molecular understanding of novel treatment paradigms in SCLC may provide the basis for future treatment designs.

Heterogeneity of molecular subtyping and therapy-related marker expression in primary tumors and paired lymph node metastases of small cell lung cancer

The classification of molecular subtypes and the identification of targetable molecules have been proposed for small cell lung cancer (SCLC) patients. Our aim was to investigate whether the expression of these markers evaluated using lymph node (LN) metastases represents that of primary tumors. We enrolled 46 surgically resected SCLC patients' primary tumors and paired mediastinal LN metastases. The protein expression of subtype-defining markers (ASCL1, NEUROD1, POU2F3, and YAP1) and therapeutic markers (DLL3, MYC, PD-L1, and MHC I) was examined by immunohistochemistry and was correlated with clinicopathological parameters and prognoses. In primary and metastatic tumors, the expression of these markers was 78.3% and 87.0%, 50.0% and 63.0%, 13.0% and 6.5%, 17.4% and 15.2%, 84.8% and 87.0%, 17.4% and 6.5%, 50.0% and 34.8%, and 60.9% and 37.0%, respectively. Positive tumor PD-L1 expression was less present in LN metastases (p = 0.015), and the same was true for MHC I expression (p = 0.036). NEUROD1 and DLL3 expression levels in metastatic tumors were stronger (p < 0.001 and p = 0.002, respectively); conversely, POU2F3, MYC, PD-L1, and MHC I expression levels were weaker (p = 0.018, p = 0.019, p = 0.001, and p < 0.001, respectively). In 15 (32.6%) patients, we observed a change in the molecular subtyping pattern, and a higher number of neuroendocrine (NE)-high phenotype patients were diagnosed when using the LN specimens (91.3% vs. 84.8%). TNM stage and postoperative chemotherapy were independent prognostic factors in surgically resected SCLC patients, and no prognostic differences were found among molecular subtypes. This study highlights the discordance of subtype-specific proteins and therapeutic markers between SCLC primary tumors and LN metastases. Additionally, our findings have therapeutic and prognostic implications and warrant further clinical investigation.

Advancement Opportunities and Endeavor of Innovative Targeted Therapies for Small Cell Lung Cancer

Small cell lung cancer (SCLC) is an intractable disease with rapid progression and high mortality, presenting a persistent obstacle impeding clinical management. Although recent advancements in immunotherapy have enhanced the response rates of platinum-based chemotherapy regimens, the emergence of acquired resistance invariably leads to recurrence and metastasis. Consequently, there is an urgent necessity to explore novel therapeutic targets and optimize existing treatment strategies. This article comprehensively reviews the currently available therapeutic modalities for SCLC. It delves into the immunologic prognostic implications by analyzing selected immune-related signatures. Moreover, it conducts an in-depth exploration of the molecular subtyping of SCLC and the associated molecular pathways to identify potential therapeutic targets. Specifically, the focus is on clinical interventions targeting delta-like ligand 3 (DLL3), elucidating its resistance mechanisms and demonstrating its notable antitumor efficacy. Furthermore, the study examines the mechanisms of chimeric antigen receptor (CAR) T and antibody-drug conjugate (ADC), covering resistance issues and strategies for optimizing resistance management, with particular emphasis being placed on analyzing the prospects and clinical value of CAR T therapy in the context of SCLC. Moreover, the effectiveness of poly ADP-ribose polymerase and ataxia telangiectasia and rad3/checkpoint kinase 1 inhibitors is discussed and underscores the advantages of combining these inhibitors with standard chemotherapy to combat chemoresistance and enhance the antitumor effects of immunotherapies. Overall, this study investigates emerging strategies for targeted therapies and optimized combination regimens to overcome resistance in SCLC and highlights future strategies for new therapeutic technologies for SCLC.

Recent Advances in the Clinical Translation of Small-Cell Lung Cancer Therapeutics

Small-cell lung cancer (SCLC) is a recalcitrant form of cancer, representing 15% of lung cancer cases globally. SCLC is classified within the range of neuroendocrine pulmonary neoplasms, exhibiting shared morphologic, ultrastructural, immunohistochemical, and molecular genomic features. It is marked by rapid proliferation, a propensity for early metastasis, and an overall poor prognosis. The current conventional therapies involve platinum-etoposide-based chemotherapy in combination with immunotherapy. Nonetheless, the rapid emergence of therapeutic resistance continues to pose substantial difficulties. The genomic profiling of SCLC uncovers significant chromosomal rearrangements along with a considerable mutation burden, typically involving the functional inactivation of the tumor suppressor genes TP53 and RB1. Identifying biomarkers and evaluating new treatments is crucial for enhancing outcomes in patients with SCLC. Targeted therapies such as topoisomerase inhibitors, DLL3 inhibitors, HDAC inhibitors, PARP inhibitors, Chk1 inhibitors, etc., have introduced new therapeutic options for future applications. In this current review, we will attempt to outline the key molecular pathways that play a role in the development and progression of SCLC, together with a comprehensive overview of the most recent advancements in the development of novel targeted treatment strategies, as well as some ongoing clinical trials against SCLC, with the goal of improving patient outcomes.

Adoptive cell therapies in thoracic malignancies: a comprehensive review

This review aims to summarize recent studies and findings within adoptive cell therapies, including tumor-infiltrating lymphocytes, genetically engineered T cell receptors, and chimeric antigen receptor T cells, in the treatment of thoracic malignancies, including non-small cell lung cancer, small cell lung cancer, and malignant pleural mesothelioma. Several trials are ongoing, and a few have reported results, suggesting that adoptive cell therapies may represent a potential treatment option for these patients, especially when checkpoint inhibition has failed. We also discuss the potential implementation of these therapies, as they present a new toxicity profile and an intrinsic financial burden. Despite the challenges to overcome, such as the accurate identification of antigens and developing strategies to improve efficacy and toxicity profiles, new cellular therapies are experiencing significant development in the field of thoracic malignancies.

Prophylactic cranial irradiation for small cell lung cancer in the era of immunotherapy and molecular subtypes

PURPOSE OF REVIEW

Small cell lung cancer (SCLC) is an aggressive disease with a poor prognosis, whereas its metastatic capacity carries a predilection for the brain. Although prophylactic cranial irradiation (PCI) has been used to address this problem, upcoming alternatives might necessitate reflection of its application in SCLC treatment.

RECENT FINDINGS

The addition of immunotherapy to treatment guidelines has provided a new strategy for the management of brain metastases. Complementation of immunotherapy with active MRI surveillance could potentially replace PCI and avoid irradiation-related cognitive side effects. SCLC's molecular profile is heterogeneous, with differential response to treatment modalities between subgroups. Investigation of these variances might be essential to improve therapeutic outcomes in SCLC patients.

SUMMARY

The role of PCI in SCLC treatment must be examined in light of immunotherapy. We summarize recent results, bearing SCLC subtypes and therapeutic vulnerabilities in mind, to derive tailored treatment strategies for SCLC patients in future settings.

Immunotherapy for Limited-Stage Small Cell Lung Cancer: Innovative Treatments and Future Perspectives

BackgroundLimited-stage small cell lung cancer (LS-SCLC) is a highly aggressive tumor characterized by a poor prognosis. While concurrent chemoradiotherapy (CCRT) remains the standard treatment, the high rates of recurrence and poor long-term survival highlight the pressing need for novel therapeutic approaches.PurposeIn recent years, the introduction of immunotherapy, particularly immune checkpoint inhibitors (ICIs), has opened new avenues for the treatment of LS-SCLC. This review highlights the clinical advancements of ICIs in CCRT, consolidation therapy, and neoadjuvant therapy, emphasizing their potential to improve progression-free survival (PFS) and overall survival (OS). This review also discusses management of immunotherapy-related side effects.Research DesignThis is a review article that synthesizes recent research findings on immunotherapy for LS-SCLC.Study SampleNot applicable (review of existing literature).Data Collection and/or AnalysisThis review summarizes key studies exploring the application of immunotherapy in limited-stage small cell lung cancer.Additionally, it examines the role of the tumor microenvironment, tumor mutation burden (TMB), and Programmed cell death 1 ligand 1(PD-L1) as biomarkers for predicting the efficacy of immunotherapy.ResultsThis review emphasizes their potential to improve PFS and OS.ConclusionsDespite the significant advancements in research, the use of ICIs in LS-SCLC continues to face challenges, including the identification of optimal treatment regimens, validation of long-term efficacy, and development of personalized predictive biomarkers. Future research should prioritize large-scale, multicenter clinical trials to refine combination therapy strategies, establish customized treatment approaches, and enhance patient outcomes.

Molecular subtypes, predictive markers and prognosis in small-cell lung carcinoma

AIMS

A new molecular subtype classification was proposed for small-cell lung carcinoma (SCLC). We aimed to further validate the classification in various SCLC patient samples using immunohistochemistry (IHC) to highlight its clinical significance.

METHODS

We analysed the protein expression of four subtype (achaete-scute family BHLH transcription factor 1 (ASCL1), neuronal differentiation 1 (NEUROD1), POU class 2 homeobox 3 (POU2F3) and Yes1-associated transcriptional regulator (YAP1)) and two predictive markers (delta-like ligand 3 (DLL3) and MYC) using IHC in 216 specimens from 195 SCLC patients, including 21 pairs of resected biopsy tumours. Associations among molecular subtypes, clinicopathological features and prognostic implications were also explored.

RESULTS

The ASCL1, NEUROD1, POU2F3, YAP1, DLL3 and MYC-positive expression rates were 70.3%, 56.9%, 14.9%, 19.0%, 75.4% and 22.6%, respectively. DLL3 expression had positive and negative associations with that of ASCL1 and POU2F3/YAP1, respectively, whereas MYC had the opposite effect. Strong associations of ASCL1 (Ρ=0.8603, p<0.0001), NEUROD1 (Ρ=0.8326, p<0.0001), POU2F3 (Ρ=0.6950, p<0.0001) and YAP1 (Ρ=0.7466, p<0.0001) expressions were detected between paired resected biopsy tumours. In addition to SCLC-A (ASCL1-dominant), SCLC-N (NEUROD1-dominant) and SCLC-P (POU2F3-dominant), unsupervised hierarchical cluster analyses identified a fourth, quadruple-negative SCLC subtype (SCLC-QN) characterised by the low expression of all four subtype-specific proteins, and 55.4% (n=108), 27.2% (n=53), 11.8% (n=23) and 5.6% (n=11) were categorised as SCLC-A, SCLC-N, SCLC-P and SCLC-QN, respectively. Significant enrichment of SCLC-P in the combined SCLC cohort was observed, and adenocarcinoma was more prevalent in SCLC-A, while large-cell neuroendocrine carcinoma was more commonly seen in SCLC-P. No survival difference was found among molecular subtypes.

CONCLUSIONS

Our results provide clinical insights into the diagnostic, prognostic and predictive significance of SCLC molecular subtype classifications.

Novel Immunohistochemical Profiling of Small-Cell Lung Cancer: Correlations Between Tumor Subtypes and Immune Microenvironment

BACKGROUND/OBJECTIVES

Small-cell lung cancer (SCLC) is a highly aggressive malignancy with an emerging molecular classification based on the expression of the transcription factors ASCL1, NEUROD1, and POU2F3. This study aimed to explore the relationship between these novel subtypes and the tumor immune microenvironment (TIME), particularly CD8+ and CD4+ tumor-infiltrating lymphocytes (TILs).

METHODS

In 51 cases of patients with SCLC, immunohistochemical (IHC) stains for ASCL1, NEUROD1, POU2F3, CD56, Ki67, CD8, and CD4 were performed. H-scores for the novel transcription factors were calculated to determine tumor subtype. CD8+ and CD4+ TIL counts were averaged across 10 high-power fields. The Kruskal-Wallis test and subsequent post hoc Dunn tests were used to determine the differences in transcription factor expression and TILs across subtypes.

RESULTS

In our cohort, 68.62% of our cases were SCLC-A, 9.80% were SCLC-N, 7.84% were SCLC-P, and 13.72% were SCLC-I. Significant differences were observed in the expression of ASCL1, NEUROD1, and POU2F3 across subtypes. CD8+ TILs were more abundant in SCLC-P and SCLC-I. CD8+ TILs were negatively correlated with ASCL1 expression (p < 0.05) and positively correlated with POU2F3 expression (p < 0.005).

CONCLUSIONS

This study highlights the need to integrate the novel SCLC classification with data regarding the TIME to better inform patient prognosis and treatment.

POU2F3-expressing intraepithelial small-cell carcinoma with mixed small-cell carcinoma and conventional-type urothelial carcinoma of the urinary bladder

Based on lineage-specific transcription factors, small-cell neuroendocrine carcinoma (SmCC) of the urinary bladder has recently been subtyped into three molecular subtypes: ASCL1, NEUROD1 and POU2F3. The latter is a master transcriptional regulator of tuft cells (TCs) which are rare solitary cells found in various mucosal epithelia such as the gastrointestinal tract, but which have not been reported in the bladder. The POU2F3 subtype shows low or absent neuroendocrine marker expression. A case of mixed SmCC and conventional-type urothelial carcinoma (CUC) of the urinary bladder with POU2F3-expressing intraepithelial small-cell carcinoma in keeping with a tuft cell phenotype, arising in association with intestinal metaplasia (IM) is described. The presence of POU2F3-expressing cells in normal urothelium, cystitis cystica glandularis and IM of the urinary bladder is demonstrated in separate cases of cystitis cystica glandularis with IM. Also, POU2F3 expression is identified in a subset of bladder SmCC.

Unveiling the Molecular Features of SCLC With a Clinical RNA Expression Panel

Introduction

The translation of gene expression profiles of SCLC to clinical testing remains relatively unexplored. In this study, gene expression variations in SCLC were evaluated to identify potential biomarkers.

Methods

RNA expression profiling was performed on 44 tumor samples from 35 patients diagnosed with SCLC using the clinically validated RNA Salah Targeted Expression Panel (RNA STEP). RNA sequencing (RNA-Seq) and immunohistochemistry were performed on two different SCLC cohorts, and correlation analyses were performed for the ASCL1, NEUROD1, POU2F3, and YAP1 genes and their corresponding proteins. RNA STEP and RNA-Seq results were evaluated for gene expression profiles and heterogeneity between SCLC primary and metastatic sites. RNA STEP gene expression profiles of independent SCLC samples (n = 35) were compared with lung adenocarcinoma (n = 160) and squamous cell carcinoma results (n = 25).

Results

The RNA STEP results were highly correlated with RNA-Seq and immunohistochemistry results. The dominant transcription regulator by RNA STEP was ASCL1 in 74.2% of the samples, NEUROD1 in 20%, and POU2F3 in 2.9%. The ASCL1, NEUROD1, and POU2F3 gene expression profiles were heterogeneous between primary and metastatic sites. SCLCs displayed markedly high expression for targetable genes DLL3, EZH2, TERT, and RET. SCLCs were found to have relatively colder immune profiles than lung adenocarcinomas and squamous cell carcinomas, characterized by lower expression of HLA genes, immune cell, and immune checkpoint genes, except the LAG3 gene.

Conclusions

Clinical-grade SCLC RNA expression profiling has value for SCLC subtyping, design of clinical trials, and identification of patients for trials and potential targeted therapy.

Adunctin E from Conamomum rubidum Induces Apoptosis in Lung Cancer via HSP90AA1 Modulation: A Network Pharmacology and In Vitro Study

Lung cancer stands out as a leading cause of death among various cancer types, highlighting the urgent need for effective anticancer drugs and the discovery of new compounds with potent therapeutic properties. Natural sources, such as the Conamomum genus, offer various bioactive compounds. Adunctin E (AE), a dihydrochalcone derived from Conamomum rubidum, exhibited several pharmacological activities, and its potential as an anticancer agent remains largely unexplored. Thus, this study aimed to elucidate its apoptotic-inducing effect and identify its molecular targets. The network pharmacology analysis led to the identification of 71 potential targets of AE against lung cancer. Subsequent gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway enrichment analyses revealed the involvement of these targets in cancer-associated signaling pathways. Notably, HSP90AA1, MAPK1, and PIK3CA emerged as key players in apoptosis. In silico molecular docking and dynamic simulations suggested a strong and stable interaction between AE and HSP90AA1. In vitro experiments further confirmed a significant apoptotic-inducing effect of AE on lung cancer cell lines A549 and H460. Furthermore, immunoblot analysis exhibited a substantial decrease in HSP90AA1 levels in response to AE treatment. These findings support the potential anticancer activity of AE through the HSP90AA1 mechanism, underscoring its promise as a novel compound worthy of further research and development for anti-lung cancer therapy.

Transcriptomic Heterogeneity of EGFR-Mutant Non-Small Cell Lung Cancer Evolution Toward Small-Cell Lung Cancer

PURPOSE

Histologic transformation from EGFR-mutant non-small cell lung cancer (NSCLC) to small-cell lung cancer (SCLC) is a key mechanism of resistance to EGFR tyrosine kinase inhibitors (TKI). However, transcriptomic changes between NSCLC and transformed SCLC (t-SCLC) remain unexplored.

EXPERIMENTAL DESIGN

We conducted whole-transcriptome analysis of 59 regions of interest through the spatial profiling of formalin-fixed, paraffin-embedded tissues obtained from 10 patients (lung adenocarcinoma, 22; combined SCLC/NSCLC, 7; and t-SCLC, 30 regions of interests). Transcriptomic profiles and differentially expressed genes were compared between pre- and post-transformed tumors.

RESULTS

Following EGFR-TKI treatment, 93.7% (15/16) of t-SCLC components evolved into neuroendocrine-high subtypes (SCLC-A or SCLC-N). The transition to t-SCLC occurred regardless of EGFR-TKI treatment and EGFR mutational status, with a notable decrease in EGFR expression (P < 0.001) at both mRNA and protein levels. Pathway analysis revealed that gene overexpression was related to epigenetic alterations in t-SCLC. Interestingly, histone deacetylase inhibitors restored EGFR expression in SNU-2962A cells and their organoid model. The synergistic effects of third-generation EGFR-TKI osimertinib and the histone deacetylase inhibitor fimepinostat were validated in both in vitro and in vivo models.

CONCLUSIONS

Our study demonstrated that most t-SCLC cases showed neuronal subtypes with low EGFR expression. Differentially expressed gene analysis and t-SCLC preclinical models identified an epigenetic modifier as a promising treatment strategy for t-SCLC.

Efficacy and safety of anlotinib plus penpulimab as second-line treatment for small cell lung cancer: A multicenter, open-label, single-arm phase II trial

BACKGROUND

Currently, the need for new therapeutic strategies involving programmed cell death protein-1 (PD-1) monoclonal antibodies in the second-line setting of small cell lung cancer (SCLC) is urgent. This study aimed to evaluate the efficacy and safety of anlotinib plus penpulimab as a second-line treatment for patients with SCLC who progressed after first-line platinum-based chemotherapy.

METHODS

This study included the patients from Cohort 4 of a single-arm, open-label, multicenter, phase II clinical trial. A safety run-in phase was performed under anlotinib (10/12 mg quaque die [QD], days 1-14) plus penpulimab (200 mg intravenously [IV], day 1) in a 21-day cycle, followed by the formal trial in which the patients received anlotinib (12 mg QD, days 1-14) plus penpulimab (200 mg IV, day 1) in a 21-day cycle. The primary endpoint of the safety run-in phase was safety. The primary endpoint of the formal trial phase was the objective response rate (ORR).

RESULTS

From April 28, 2020, to November 24, 2020, 21 patients were enrolled from 11 hospitals, including 2 in the safety run-in phase and 19 in the formal trial phase. In the formal trial phase, the ORR was 42.1% (8/19; 95% confidence interval [CI]: 17.7-66.6%). The median progression-free survival was 4.8 months (95% CI: 2.9-11.3 months), and the median overall survival was 13.0 months (95% CI: 4.6-not applicable [NA] months). The incidence of ≥grade 3 treatment-related adverse events (TRAEs) was 52.4% (11/21), and the incidence of treatment-related serious adverse events (AEs) was 28.6% (6/21). Two AE-related deaths occurred. The most common AEs were hypertension (57.1%, 12/21), hypothyroidism (42.9%, 9/21), and hypertriglyceridemia (38.1%, 8/21).

CONCLUSIONS

In patients with SCLC who progressed after first-line platinum-based chemotherapy, the second-line anlotinib plus penpulimab treatment demonstrates promising anti-cancer activity and a manageable safety profile, which warrants further investigation.

TRIAL REGISTRATION

No. NCT04203719, https://clinicaltrials.gov/.

Prognostic value of baseline clinicopathological characteristics in first-line chemotherapy ± immunotherapy for extensive-stage small cell lung cancer: a retrospective cohort study

Background

The integration of chemotherapy and immunotherapy as a first-line treatment for extensive-stage small cell lung cancer (ES-SCLC) has been adopted in clinical practice, yet the response to immune checkpoint inhibitors (ICIs) is variable, benefiting only a fraction of patients. The current absence of reliable biomarkers for predicting treatment response and prognosis represents a significant gap in knowledge, hindering the optimization of patient stratification and treatment planning. This retrospective cohort study aims to assess the potential predictive and prognostic significance of clinicopathological baseline features in ES-SCLC patients.

Methods

Our study retrospectively analyzed the data of consecutive patients with ES-SCLC treated with first-line etoposide plus platinum chemotherapy ± immunotherapy at The Affiliated Lihuili Hospital of Ningbo University from April 2017 to April 2023. Data on clinical information, serum laboratory indicators, pathological immunohistochemical markers, and progression-free survival (PFS) times were collected. Univariate and multivariate Cox regression analyses were employed to determine whether these indicators could serve as independent prognostic factors for PFS. Further, potential predictive markers for treatment efficacy were identified using a Cox regression model that incorporated an interaction term between treatment modality and the indicator.

Results

A total of 121 patients with ES-SCLC were enrolled in the study, of whom 62 received chemotherapy alone, and 59 received chemotherapy in combination with immunotherapy. Compared to chemotherapy alone, the addition of immunotherapy to first-line chemotherapy significantly extended the PFS time [P<0.001; hazard ratio (HR) =0.42; 95% confidence interval (CI): 0.28, 0.64] of the ES-SCLC patients. The multivariate analysis revealed that an immunochemotherapy regimen (P<0.001, HR =0.40; 95% CI: 0.24, 0.68), a low-density lipoprotein (LDL) level of >1.8 mmol/L (P=0.02; HR =0.41; 95% CI: 0.20, 0.85) were independent prognostic factors of favorable PFS in the first-line treatment of all ES-SCLC, while a lactate dehydrogenase (LDH) level of >273 U/L (P=0.04; HR =1.78; 95% CI: 1.03, 3.07), a neuron-specific enolase (NSE) concentration of >102.6 ng/mL (P=0.009; HR =6.49; 95% CI: 1.60, 26.32), an apolipoprotein A1 (ApoA1) concentration of >0.9 g/L (P<0.001; HR =4.15; 95% CI: 1.98, 8.71), and an apolipoprotein B (ApoB) concentration of >0.8 g/L (P=0.002; HR =2.24; 95% CI: 1.34, 3.75) were independent prognostic factors of poorer PFS. Further, the interaction effect analysis demonstrated that an LDL level of >1.8 mmol/L and the absence of bone metastasis were potential predictors of an improved response to ICI therapy compared to chemotherapy alone.

Conclusions

This study showed the survival benefit of receiving a chemoimmunotherapy regimen as the first-line treatment in a real-world scenario. It also suggests the prognostic significance of pre-treatment LDL, LDH, NSE, ApoA1, and ApoB with optimal cut-off values in the first-line treatment of all ES-SCLC, and the potential utility of baseline LDL level or the presence of bone metastasis in guiding first-line treatment strategies.

Emerging advances in defining the molecular and therapeutic landscape of small-cell lung cancer

Small-cell lung cancer (SCLC) has traditionally been considered a recalcitrant cancer with a dismal prognosis, with only modest advances in therapeutic strategies over the past several decades. Comprehensive genomic assessments of SCLC have revealed that most of these tumours harbour deletions of the tumour-suppressor genes TP53 and RB1 but, in contrast to non-small-cell lung cancer, have failed to identify targetable alterations. The expression status of four transcription factors with key roles in SCLC pathogenesis defines distinct molecular subtypes of the disease, potentially enabling specific therapeutic approaches. Overexpression and amplification of MYC paralogues also affect the biology and therapeutic vulnerabilities of SCLC. Several other attractive targets have emerged in the past few years, including inhibitors of DNA-damage-response pathways, epigenetic modifiers, antibody-drug conjugates and chimeric antigen receptor T cells. However, the rapid development of therapeutic resistance and lack of biomarkers for effective selection of patients with SCLC are ongoing challenges. Emerging single-cell RNA sequencing data are providing insights into the plasticity and intratumoural and intertumoural heterogeneity of SCLC that might be associated with therapeutic resistance. In this Review, we provide a comprehensive overview of the latest advances in genomic and transcriptomic characterization of SCLC with a particular focus on opportunities for translation into new therapeutic approaches to improve patient outcomes.

Treatment Response Biomarkers: Working Toward Personalized Radiotherapy for Lung Cancer

Owing to major advances in the field of radiation oncology, patients with lung cancer can now receive technically individualized radiotherapy treatments. Nevertheless, in the era of precision oncology, radiotherapy-based treatment selection needs to be improved as many patients do not benefit or are not offered optimum therapies. Cost-effective robust biomarkers can address this knowledge gap and lead to individuals being offered more bespoke treatments leading to improved outcome. This narrative review discusses some of the current achievements and challenges in the realization of personalized radiotherapy delivery in patients with lung cancer.

Circulating tumor cells: advancing personalized therapy in small cell lung cancer patients

Small cell lung cancer (SCLC) is a highly aggressive cancer with a dismal 5-year survival of < 7%, despite the addition of immunotherapy to first-line chemotherapy. Specific tumor biomarkers, such as delta-like ligand 3 (DLL3) and schlafen11 (SLFN11), may enable the selection of more efficacious, novel immunomodulating targeted treatments like bispecific T-cell engaging monoclonal antibodies (tarlatamab) and chemotherapy with PARP inhibitors. However, obtaining a tissue biopsy sample can be challenging in SCLC. Circulating tumor cells (CTCs) have the potential to provide molecular insights into a patient's cancer through a "simple" blood test. CTCs have been studied for their prognostic ability in SCLC; however, their value in guiding treatment decisions is yet to be elucidated. This review explores novel and promising targeted therapies in SCLC, summarizes current knowledge of CTCs in SCLC, and discusses how CTCs can be utilized for precision medicine.

The Evolving Scenario of ES-SCLC Management: From Biology to New Cancer Therapeutics

Small cell lung cancer (SCLC) is an aggressive neuroendocrine carcinoma accounting for 15% of lung cancers with dismal survival outcomes. Minimal changes in therapy and prognosis have occurred in SCLC for the past four decades. Recent progress in the treatment of extensive-stage disease (ES-SCLC) has been marked by incorporating immune checkpoint inhibitors (ICIs) into platinum-based chemotherapy, leading to modest improvements. Moreover, few second-line-and-beyond treatment options are currently available. The main limitation for the molecular study of SCLC has been the scarcity of samples, because only very early diseases are treated with surgery and biopsies are not performed when the disease progresses. Despite all these difficulties, in recent years we have come to understand that SCLC is not a homogeneous disease. At the molecular level, in addition to the universal loss of retinoblastoma (RB) and TP53 genes, a recent large molecular study has identified other mutations that could serve as targets for therapy development or patient selection. In recent years, there has also been the identification of new genetic subtypes which have shown us how intertumor heterogeneity exists. Moreover, SCLC can also develop intratumoral heterogeneity linked mainly to the concept of cellular plasticity, mostly due to the development of resistance to therapies. The aim of this review is to quickly present the current standard of care of ES-SCLC, to focus on the molecular landscapes and subtypes of SCLC, subsequently present the most promising therapeutic strategies under investigation, and finally recap the future directions of ongoing clinical trials for this aggressive disease which still remains a challenge.

Exosomal Proteomics: Unveiling Novel Insights into Lung Cancer

Although significant progress has been made in early lung cancer screening over the past decade, it remains one of the most prevalent and deadliest forms of cancer worldwide. Exosomal proteomics has emerged as a transformative field in lung cancer research, with the potential to redefine diagnostics, prognostic assessments, and therapeutic strategies through the lens of precision medicine. This review discusses recent advances in exosome-related proteomic and glycoproteomic technologies, highlighting their potential to revolutionise lung cancer treatment by addressing issues of heterogeneity, integrating multiomics data, and utilising advanced analytical methods. While these technologies show promise, there are obstacles to overcome before they can be widely implemented, such as the need for standardization, gaps in clinical application, and the importance of dynamic monitoring. Future directions should aim to overcome the challenges to fully utilize the potential of exosomal proteomics in lung cancer. This promises a new era of personalized medicine that leverages the molecular complexity of exosomes for groundbreaking advancements in detection, prognosis, and treatment.

Pediatric Cancer Drug Development: Leveraging Insights in Cancer Biology and the Evolving Regulatory Landscape to Address Challenges and Guide Further Progress

The discovery and development of anticancer drugs for pediatric patients have historically languished when compared to both past and recent activity in drug development for adult patients, notably the dramatic spike of targeted and immune-oncology therapies. The reasons for this difference are multifactorial. Recent changes in the regulatory landscape surrounding pediatric cancer drug development and the understanding that some pediatric cancers are driven by genetic perturbations that also drive disparate adult cancers afford new opportunities. The unique cancer-initiating events and dependencies of many pediatric cancers, however, require additional pediatric-specific strategies. Research efforts to unravel the underlying biology of pediatric cancers, innovative clinical trial designs, model-informed drug development, extrapolation from adult data, addressing the unique considerations in pediatric patients, and use of pediatric appropriate formulations, should all be considered for efficient development and dosage optimization of anticancer drugs for pediatric patients.

Application of Small Cell Lung Cancer Molecular Subtyping Markers to Small Cell Neuroendocrine Carcinoma of the Cervix: NEUROD1 as a Poor Prognostic Factor

Cervical small cell neuroendocrine carcinoma (CSCNEC) is a rare, aggressive type of cervical cancer. The treatment for CSCNEC follows the chemotherapeutic regimens used for small cell lung cancer (SCLC), with which it shares similar clinical and histologic features. For the first time, we applied neuroendocrine (NE) and SCLC molecular subtyping immunohistochemical markers [achaete-scute homolog 1 (ASCL1), neurogenic differentiation factor 1 (NEUROD1), POU class 2 homeobox 3 (POU2F3), and yes-associated protein 1] in 45 patients with CSCNEC. For the combined NE score, 51.1% of NE-high and 48.9% of NE-low subtypes were identified. The NE-high subtype tended to show worse progression-free survival and overall survival (OS) than the NE-low subtype ( P =0.059 and P =0.07, respectively). Applying the SCLC molecular subtyping, 53.3% of cases were identified as NEUROD1-dominant, 17.8% as ASCL1-dominant, 13.3% as YAP-dominant, and 4.4% as POU2F3-dominant, while 11.1% of cases showed negative expression for all markers; the distribution was different from that of SCLC. The NEUROD1-dominant subtype exhibited the worst OS, while the POU2F3 subtype exhibited the best OS ( P =0.003), similar to SCLC. In addition, the ASCL1-dominant and NEUROD1-dominant subtypes showed high NE scores, while yes-associated protein 1-dominant and POU2F3-dominant subtypes showed low NE scores ( P =0.008). In multivariate analysis, the NEUROD1 expression was further identified as the independent prognostic factor for worse OS, together with the high FIGO stage. CSCNEC was revealed to be a heterogeneous disease with different biological phenotypes and to share some similarities and differences with SCLC. Regarding the ongoing development of tailored treatments based on biomarkers in SCLC, the application of biomarker-driven individualized therapy would improve clinical outcomes in patients with CSCNEC.

Small cells - big issues: biological implications and preclinical advancements in small cell lung cancer

Current treatment guidelines refer to small cell lung cancer (SCLC), one of the deadliest human malignancies, as a homogeneous disease. Accordingly, SCLC therapy comprises chemoradiation with or without immunotherapy. Meanwhile, recent studies have made significant advances in subclassifying SCLC based on the elevated expression of the transcription factors ASCL1, NEUROD1, and POU2F3, as well as on certain inflammatory characteristics. The role of the transcription regulator YAP1 in defining a unique SCLC subset remains to be established. Although preclinical analyses have described numerous subtype-specific characteristics and vulnerabilities, the so far non-existing clinical subtype distinction may be a contributor to negative clinical trial outcomes. This comprehensive review aims to provide a framework for the development of novel personalized therapeutic approaches by compiling the most recent discoveries achieved by preclinical SCLC research. We highlight the challenges faced due to limited access to patient material as well as the advances accomplished by implementing state-of-the-art models and methodologies.

C-Myc protein expression indicates unfavorable clinical outcome in surgically resected small cell lung cancer

BACKGROUND

By being highly involved in the tumor evolution and disease progression of small cell lung cancer (SCLC), Myc family members (C-Myc, L-Myc, and N-Myc) might represent promising targetable molecules. Our aim was to investigate the expression pattern and prognostic relevance of these oncogenic proteins in an international cohort of surgically resected SCLC tumors.

METHODS

Clinicopathological data and surgically resected tissue specimens from 104 SCLC patients were collected from two collaborating European institutes. Tissue sections were stained by immunohistochemistry (IHC) for all three Myc family members and the recently introduced SCLC molecular subtype-markers (ASCL1, NEUROD1, POU2F3, and YAP1).

RESULTS

IHC analysis showed C-Myc, L-Myc, and N-Myc positivity in 48%, 63%, and 9% of the specimens, respectively. N-Myc positivity significantly correlated with the POU2F3-defined molecular subtype (r = 0.6913, p = 0.0056). SCLC patients with C-Myc positive tumors exhibited significantly worse overall survival (OS) (20 vs. 44 months compared to those with C-Myc negative tumors, p = 0.0176). Ultimately, in a multivariate risk model adjusted for clinicopathological and treatment confounders, positive C-Myc expression was confirmed as an independent prognosticator of impaired OS (HR 1.811, CI 95% 1.054-3.113, p = 0.032).

CONCLUSIONS

Our study provides insights into the clinical aspects of Myc family members in surgically resected SCLC tumors. Notably, besides showing that positivity of Myc family members varies across the patients, we also reveal that C-Myc protein expression independently correlates with worse survival outcomes. Further studies are warranted to investigate the role of Myc family members as potential prognostic and predictive markers in this hard-to-treat disease.

ATOH1, TFAP2B, and CEACAM6 as Immunohistochemical Markers to Distinguish Merkel Cell Carcinoma and Small Cell Lung Cancer

Merkel cell carcinoma (MCC) and small cell lung cancer (SCLC) can be histologically similar. Immunohistochemistry (IHC) for cytokeratin 20 (CK20) and thyroid transcription factor 1 (TTF-1) are commonly used to differentiate MCC from SCLC; however, these markers have limited sensitivity and specificity. To identify new diagnostic markers, we performed differential gene expression analysis on transcriptome data from MCC and SCLC tumors. Candidate markers included atonal BHLH transcription factor 1 (ATOH1) and transcription factor AP-2β (TFAP2B) for MCC, as well as carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) for SCLC. Immunostaining for CK20, TTF-1, and new candidate markers was performed on 43 MCC and 59 SCLC samples. All three MCC markers were sensitive and specific, with CK20 and ATOH1 staining 43/43 (100%) MCC and 0/59 (0%) SCLC cases and TFAP2B staining 40/43 (93%) MCC and 0/59 (0%) SCLC cases. TTF-1 stained 47/59 (80%) SCLC and 1/43 (2%) MCC cases. CEACAM6 stained 49/59 (83%) SCLC and 0/43 (0%) MCC cases. Combining CEACAM6 and TTF-1 increased SCLC detection sensitivity to 93% and specificity to 98%. These data suggest that ATOH1, TFAP2B, and CEACAM6 should be explored as markers to differentiate MCC and SCLC.

Tumor- and circulating-free DNA methylation identifies clinically relevant small cell lung cancer subtypes

Small cell lung cancer (SCLC) is an aggressive malignancy composed of distinct transcriptional subtypes, but implementing subtyping in the clinic has remained challenging, particularly due to limited tissue availability. Given the known epigenetic regulation of critical SCLC transcriptional programs, we hypothesized that subtype-specific patterns of DNA methylation could be detected in tumor or blood from SCLC patients. Using genomic-wide reduced-representation bisulfite sequencing (RRBS) in two cohorts totaling 179 SCLC patients and using machine learning approaches, we report a highly accurate DNA methylation-based classifier (SCLC-DMC) that can distinguish SCLC subtypes. We further adjust the classifier for circulating-free DNA (cfDNA) to subtype SCLC from plasma. Using the cfDNA classifier (cfDMC), we demonstrate that SCLC phenotypes can evolve during disease progression, highlighting the need for longitudinal tracking of SCLC during clinical treatment. These data establish that tumor and cfDNA methylation can be used to identify SCLC subtypes and might guide precision SCLC therapy.

Prognostic factors in extensive-stage small cell lung cancer patients with organ-specific metastasis: unveiling commonalities and disparities

BACKGROUND

This study aimed to identify shared and distinct prognostic factors related to organ-specific metastases (liver, lung, bone, and brain) in extensive-stage small cell lung cancer (ES-SCLC) patients, then construct nomograms for survival prediction.

METHODS

Patient data for ES-SCLC were from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2019. Kaplan-Meier analysis was applied to estimate overall survival (OS), and Cox regression was used to identify prognostic factors. A Venn diagram was utilized to distinguish common and unique prognostic factors among the variables assessed. These identified prognostic factors were used to formulate a nomogram, and its predictive accuracy and reliability were evaluated using C-indexes, calibration curves, and receiver operating characteristic (ROC) curves.

RESULTS

A total of 24,507 patients diagnosed with ES-SCLC exhibiting metastases to the liver, lung, bone, and brain were included. The 6-month, 1-year, and 2-year OS rates were 46.1%, 19.7%, and 5.0%, respectively. Patients with liver metastasis demonstrated the most unfavorable prognosis, with a 1-year OS rate of 14.5%, while those with brain metastasis had a significantly better prognosis with a 1-year OS rate of 21.6%. The study identified seven common factors associated with a poor prognosis in ES-SCLC patients with organ-specific metastases: older age, male sex, unmarried status, higher T stage, presence of other metastases, and combination radiotherapy and chemotherapy. Furthermore, specific prognostic factors were identified for patients with metastasis to the liver, bone, and brain, including paired tumors, lack of surgical treatment at the primary site, and household income, respectively. To facilitate prognostic predictions, four nomograms were developed and subsequently validated. The performance of these nomograms was assessed using calibration curves, C-indexes, and the area under the curve (AUC), all of which consistently indicated good predictive accuracy and reliability.

CONCLUSIONS

Patients diagnosed with ES-SCLC with organ-specific metastases revealed shared and distinct prognostic factors. The nomograms developed from these factors demonstrated good performance and can serve valuable clinical tools to predict the prognosis of ES-SCLC patients with organ-specific metastases.

Transformation to small cell lung cancer is irrespective of EGFR and accelerated by SMAD4-mediated ASCL1 transcription independently of RB1 in non-small cell lung cancer

OBJECTIVES

Histological transformation to small cell lung cancer (SCLC) has been identified as a mechanism of TKIs resistance in EGFR-mutant non-small cell lung cancer (NSCLC). We aim to explore the prevalence of transformation in EGFR-wildtype NSCLC and the mechanism of SCLC transformation, which are rarely understood.

METHODS

We reviewed 1474 NSCLC patients to investigate the NSCLC-to-SCLC transformed cases and the basic clinical characteristics, driver gene status and disease course of them. To explore the potential functional genes in SCLC transformation, we obtained pre- and post-transformation specimens and subjected them to a multigene NGS panel involving 416 cancer-related genes. To validate the putative gene function, we established knocked-out models by CRISPR-Cas 9 in HCC827 and A549-TP53-/- cells and investigated the effects on tumor growth, drug sensitivity and neuroendocrine phenotype in vitro and in vivo. We also detected the expression level of protein and mRNA to explore the molecular mechanism involved.

RESULTS

We firstly reported an incidence rate of 9.73% (11/113) of SCLC transformation in EGFR-wildtype NSCLC and demonstrated that SCLC transformation is irrespective of EGFR mutation status (P = 0.16). We sequenced 8 paired tumors and identified a series of mutant genes specially in transformed SCLC such as SMAD4, RICTOR and RET. We firstly demonstrated that SMAD4 deficiency can accelerate SCLC transition by inducing neuroendocrine phenotype regardless of RB1 status in TP53-deficient NSCLC cells. Further mechanical experiments identified the SMAD4 can regulate ASCL1 transcription competitively with Myc in NSCLC cells and Myc inhibitor acts as a potential subsequent treatment agent.

CONCLUSIONS

Transformation to SCLC is irrespective of EFGR status and can be accelerated by SMAD4 in non-small cell lung cancer. Myc inhibitor acts as a potential therapeutic drug for SMAD4-mediated resistant lung cancer. Video Abstract.

Advancing immunotherapy in small cell lung cancer

Small cell lung cancer (SCLC) is a rapidly progressive neuroendocrine carcinoma that, until recently, had a very small armamentarium of effective treatments. Advances in DNA sequencing and whole transcriptomics have delineated key subtypes; therefore, SCLC is no longer viewed as a homogeneous cancer. Chemoimmunotherapy with PD1 blockade is now the standard of care for advanced disease, and ongoing research efforts are moving this strategy into the limited stage setting. Combination strategies of immunotherapy with radiation are also under active clinical trial in both limited and extensive stage disease. PLAIN LANGUAGE SUMMARY: Small cell lung cancer (SCLC) is a rapidly progressive neuroendocrine carcinoma that, until recently, had a very small armamentarium of effective treatments. Chemoimmunotherapy with immune check point inhibitors is now the standard of care for advanced disease. This comprehensive review provides an overview of current treatment strategies for SCLC, unmet needs in this patient population, and emerging treatment strategies incorporating immunotherapy that will hopefully further improve outcomes for patients.

Entinostat Enhances the Efficacy of Chemotherapy in Small Cell Lung Cancer Through S-phase Arrest and Decreased Base Excision Repair

PURPOSE

Acquired chemoresistance is a frequent event in small cell lung cancer (SCLC), one of the deadliest human malignancies. Histone deacetylase inhibitors (HDACi) have been shown to synergize with different chemotherapeutic agents including cisplatin. Accordingly, we aimed to investigate the dual targeting of HDAC inhibition and chemotherapy in SCLC.

EXPERIMENTAL DESIGN

The efficacy of HDACi and chemotherapy in SCLC was investigated both in vitro and in vivo. Synergistic drug interactions were calculated based on the HSA model (Combenefit software). Results from the proteomic analysis were confirmed via ICP-MS, cell-cycle analysis, and comet assays.

RESULTS

Single entinostat- or chemotherapy significantly reduced cell viability in human neuroendocrine SCLC cells. The combination of entinostat with either cisplatin, carboplatin, irinotecan, epirubicin, or etoposide led to strong synergy in a subset of resistant SCLC cells. Combination treatment with entinostat and cisplatin significantly decreased tumor growth in vivo. Proteomic analysis comparing the groups of SCLC cell lines with synergistic and additive response patterns indicated alterations in cell-cycle regulation and DNA damage repair. Cell-cycle analysis revealed that cells exhibiting synergistic drug responses displayed a shift from G1 to S-phase compared with cells showing additive features upon dual treatment. Comet assays demonstrated more DNA damage and decreased base excision repair in SCLC cells more responsive to combination therapy.

CONCLUSIONS

In this study, we decipher the molecular processes behind synergistic interactions between chemotherapy and HDAC inhibition. Moreover, we report novel mechanisms to overcome drug resistance in SCLC, which may be relevant to increasing therapeutic success.

Clinical insights into small cell lung cancer: Tumor heterogeneity, diagnosis, therapy, and future directions

Small cell lung cancer (SCLC) is characterized by rapid growth and high metastatic capacity. It has strong epidemiologic and biologic links to tobacco carcinogens. Although the majority of SCLCs exhibit neuroendocrine features, an important subset of tumors lacks these properties. Genomic profiling of SCLC reveals genetic instability, almost universal inactivation of the tumor suppressor genes TP53 and RB1, and a high mutation burden. Because of early metastasis, only a small fraction of patients are amenable to curative-intent lung resection, and these individuals require adjuvant platinum-etoposide chemotherapy. Therefore, the vast majority of patients are currently being treated with chemoradiation with or without immunotherapy. In patients with disease confined to the chest, standard therapy includes thoracic radiotherapy and concurrent platinum-etoposide chemotherapy. Patients with metastatic (extensive-stage) disease are treated with a combination of platinum-etoposide chemotherapy plus immunotherapy with an anti-programmed death-ligand 1 monoclonal antibody. Although SCLC is initially very responsive to platinum-based chemotherapy, these responses are transient because of the development of drug resistance. In recent years, the authors have witnessed an accelerating pace of biologic insights into the disease, leading to the redefinition of the SCLC classification scheme. This emerging knowledge of SCLC molecular subtypes has the potential to define unique therapeutic vulnerabilities. Synthesizing these new discoveries with the current knowledge of SCLC biology and clinical management may lead to unprecedented advances in SCLC patient care. Here, the authors present an overview of multimodal clinical approaches in SCLC, with a special focus on illuminating how recent advancements in SCLC research could accelerate clinical development.

A plasma miRNA-based classifier for small cell lung cancer diagnosis

Introduction

Small cell lung cancer (SCLC) is characterized by poor prognosis and challenging diagnosis. Screening in high-risk smokers results in a reduction in lung cancer mortality, however, screening efforts are primarily focused on non-small cell lung cancer (NSCLC). SCLC diagnosis and surveillance remain significant challenges. The aberrant expression of circulating microRNAs (miRNAs/miRs) is reported in many tumors and can provide insights into the pathogenesis of tumor development and progression. Here, we conducted a comprehensive assessment of circulating miRNAs in SCLC with a goal of developing a miRNA-based classifier to assist in SCLC diagnoses.

Methods

We profiled deregulated circulating cell-free miRNAs in the plasma of SCLC patients. We tested selected miRNAs on a training cohort and created a classifier by integrating miRNA expression and patients' clinical data. Finally, we applied the classifier on a validation dataset.

Results

We determined that miR-375-3p can discriminate between SCLC and NSCLC patients, and between SCLC and Squamous Cell Carcinoma patients. Moreover, we found that a model comprising miR-375-3p, miR-320b, and miR-144-3p can be integrated with race and age to distinguish metastatic SCLC from a control group.

Discussion

This study proposes a miRNA-based biomarker classifier for SCLC that considers clinical demographics with specific cut offs to inform SCLC diagnosis.

POU2F3: A Sensitive and Specific Diagnostic Marker for Neuroendocrine-low/negative Small Cell Lung Cancer

POU2F3 (POU class 2 homeobox 3) is a novel transcription factor used to define the special molecular subtype of small cell lung cancer (SCLC) known as SCLC-P. Nevertheless, the sensitivity and specificity of POU2F3 immunohistochemical (IHC) staining have not been fully investigated. In this study, we explored the expression of POU2F3 by IHC in a large cohort of SCLC clinical samples (n=246), other common lung cancer types (n=2207), and various other cancer types (n=194). The results showed that POU2F3 was strongly nuclear stained in 13.41% (33/246) of SCLC cases, with negative or minimal labeling for thyroid transcription factor-1 and neuroendocrine (NE) markers. Compared with POU2F3-negative SCLC, SCLC-P harbored fewer TP53 and RB1 mutations. POU2F3 was also expressed in 3.13% (8/256) of squamous cell carcinomas (SCCs) and 20% (2/10) of large cell NE carcinomas (LCNECs), whereas other lung cancer types were negative. In addition to lung cancer, POU2F3 was positive in 22.2% (4/18) of thymic tumors. All other tumors were POU2F3-negative except for thymic carcinoma, although sparsely distributed weak nuclear staining was observed in lung adenocarcinoma, cervical SCC, and colorectal carcinoma. The sensitivity and specificity of POU2F3 in NE-low/negative SCLC were 82.1% and 99.4%, respectively. Notably, some rare unique patterns of POU2F3 expression were observed. One case of thymic SCC was characterized by diffuse and uniform cytomembrane staining. One case of esophageal NE tumor was nuclear-positive, while the normal proliferating squamous epithelium was strongly membrane-stained. This is the largest cohort of clinical samples to confirm that POU2F3 is a highly sensitive and specific diagnostic marker for NE-low/negative SCLC.

Progress in radiotherapy for small-cell lung cancer

Small-cell lung cancer (SCLC) is a highly aggressive neuroendocrine tumor that is prone to spread extensively. Compared to non-small-cell lung cancer (NSCLC), SCLC treatment progresses slowly. Although SCLC is highly sensitive to chemotherapy during the initial treatment, most patients still experience resistance and recurrence after receiving chemotherapy. A meta-analysis demonstrated that thoracic radiotherapy (TRT) improves overall survival in SCLC. The results of the CALGB and CONVERT trials provide evidence for the efficacy of once-daily high-dose TRT. TRT at 60 Gy administered twice daily significantly improved survival without increasing toxicity. The long-standing debate over the optimal timing of radiotherapy has not been fully resolved. SBRT has excellent local control rates and is a safe and effective treatment option for patients with stage I or II SCLC. Prophylactic cranial irradiation (PCI) is used to reduce treatment-related neurotoxicity to the extent that there has been a recent discussion on whether magnetic resonance imaging (MRI) monitoring can replace PCI. Radiotherapy combined with immunotherapy significantly improves the survival rate of patients with NSCLC; however, its clinical effectiveness has not been systematically explored in patients with SCLC. Therefore, we summarize the evolving therapeutic strategies, (TRT for limited stage-SCLC and consolidative TRT for extensive stage-SCLC) and improved radiotherapy techniques (role of SBRT in stage I or II node-negative SCLC, progress of PCI, and stereotactic radiosurgery), and discuss the possibilities and prospects of radiotherapy combined with immunotherapy for SCLC.

Whole-exome and targeted gene sequencing of large-cell lung carcinoma reveals recurrent mutations in the PI3K pathway

BACKGROUND

Large cell lung carcinoma (LCLC) is an exceptionally aggressive disease with a poor prognosis. At present, little is known about the molecular pathology of LCLC.

METHODS

Ultra-deep sequencing of cancer-related genes and exome sequencing were used to detect the LCLC mutational in 118 tumor-normal pairs. The cell function test was employed to confirm the potential carcinogenic mutation of PI3K pathway.

RESULTS

The mutation pattern is determined by the predominance of A > C mutations. Genes with a significant non-silent mutation frequency (FDR) < 0.05) include TP53 (47.5%), EGFR (13.6%) and PTEN (12.1%). Moreover, PI3K signaling (including EGFR, FGRG4, ITGA1, ITGA5, and ITGA2B) is the most mutated pathway, influencing 61.9% (73/118) of the LCLC samples. The cell function test confirmed that the potential carcinogenic mutation of PI3K pathway had a more malignant cell function phenotype. Multivariate analysis further revealed that patients with the PI3K signaling pathway mutations have a poor prognosis (P = 0.007).

CONCLUSIONS

These results initially identified frequent mutation of PI3K signaling pathways in LCLC and indicate potential targets for the treatment of this fatal type of LCLC.

Advancements in small cell lung cancer

Small cell lung cancer (SCLC) is a recalcitrant cancer with an urgent need for novel therapeutics, preclinical models, and elucidation of the molecular pathways responsible for its rapid resistance. Recently, there have been many significant advancements in our knowledge of SCLC that led to the development of novel treatments. This review will go over the recent attempts to provide new molecular subcategorization of SCLC, recent breakthroughs in various systemic treatments including immunotherapy, targeted therapy, cellular therapy, as well as advancements in radiation therapy.

Adebrelimab plus chemotherapy vs. chemotherapy for treatment of extensive-stage small-cell lung cancer from the US and Chinese healthcare sector perspectives: a cost-effectiveness analysis to inform drug pricing

Purpose: The aim of this study was to evaluate the cost-effectiveness of a recently approved first-line therapy (adebrelimab plus chemotherapy vs. chemotherapy alone) for patients with extensive-stage small-cell lung cancer (ES-SCLC) in the US and China, and to estimate the reasonable range of adebrelimab price from the decision-makers. Methods: Several partitioned survival models were built to compare the cost and effectiveness of adebrelimab plus chemotherapy vs. chemotherapy alone over a 10-year time horizon. Clinical efficacy and safety data were extracted from the CAPSTONE-1 trial. Costs and utilities were obtained from previously published studies. Sensitivity, scenario and subgroup analyses were performed to explore the uncertainty of the model outcomes. Price simulation was conducted at three thresholds of willingness-to-pay (WTP), including WTP of $100,000 in the US and of $37,422 in China, 0.5WTP of $50,000 in the US and of $18,711 in China, and 1.5WTP of 150,000 in the US and of $56,133 in China. Findings: Base-case analysis at $1382.82/600 mg of adebrelimab price indicated that adebrelimab plus chemotherapy would be cost-effective in the US at the WTP threshold of $100,000, but not in China at the WTP threshold of $37,422. If PAP was taken into account, the regimen would be cost-effective in China at the given WTP. The results of price simulation indicated that adebrelimab plus chemotherapy was completely favored in the US if adebrelimab price was less than $8894.98/600 mg (total quality-adjusted life years [QALYs] were calculated with progression-based utility [PB-utility]) or $8912.51/600 mg (total QALYs were calculated with time-to-death utility [TTD-utility]) at the WTP threshold of $100,000; if adebrelimab price was reduced by at least $202.03/600 mg (total QALYs were calculated with PB-utility) or $103.06/600 mg (total QALYs were calculated with TTD-utility), the regimen was also cost-effective in China without PAP at the WTP threshold of $37,422. The above results were stable in the sensitivity analyses. Subgroup analysis found that the subgroup with better survival benefits tended to have a higher probability of cost-effectiveness, which was also associated with adebrelimab price. Implications: First-line adebrelimab plus chemotherapy represented a dominant treatment strategy comparing with chemotherapy alone in the US and also did in China with PAP at $1382.82/600 mg of adebrelimab price. Decision-makers could benefit from pricing strategy provided by this study in making optimal decisions. More evidences were needed to verify and improve the results.

Orchestrating smart therapeutics to achieve optimal treatment in small cell lung cancer: recent progress and future directions

Small cell lung cancer (SCLC) is a recalcitrant malignancy with elusive mechanism of pathogenesis and dismal prognosis. Over the past decades, platinum-based chemotherapy has been the backbone treatment for SCLC. However, subsequent chemoresistance after initial effectiveness urges researchers to explore novel therapeutic targets of SCLC. Recent years have witnessed significant improvements in targeted therapy in SCLC. New molecular candidates such as Ataxia telangiectasia and RAD3-related protein (ATR), WEE1, checkpoint kinase 1 (CHK1) and poly-ADP-ribose polymerase (PARP) have shown promising therapeutic utility in SCLC. While immune checkpoint inhibitor (ICI) has emerged as an indispensable treatment modality for SCLC, approaches to boost efficacy and reduce toxicity as well as selection of reliable biomarkers for ICI in SCLC have remained elusive and warrants our further investigation. Given the increasing importance of precision medicine in SCLC, optimal subtyping of SCLC using multi-omics have gradually applied into clinical practice, which may identify more drug targets and better tailor treatment strategies to each individual patient. The present review summarizes recent progress and future directions in SCLC. In addition to the emerging new therapeutics, we also focus on the establishment of predictive model for early detection of SCLC. More importantly, we also propose a multi-dimensional model in the prognosis of SCLC to ultimately attain the goal of accurate treatment of SCLC.

SDH mutations, as potential predictor of chemotherapy prognosis in small cell lung cancer patients

PURPOSE

Small cell lung cancer (SCLC) is an aggressive and rapidly progressive malignant tumor characterized by a poor prognosis. Chemotherapy remains the primary treatment in clinical practice; however, reliable biomarkers for predicting chemotherapy outcomes are scarce.

METHODS

In this study, 78 SCLC patients were stratified into "good" or "poor" prognosis cohorts based on their overall survival (OS) following surgery and chemotherapeutic treatment. Next-generation sequencing was employed to analyze the mutation status of 315 tumorigenesis-associated genes in tumor tissues obtained from the patients. The random forest (RF) method, validated by the support vector machine (SVM), was utilized to identify single nucleotide mutations (SNVs) with predictive power. To verify the prognosis effect of SNVs, samples from the cbioportal database were utilized.

RESULTS

The SVM and RF methods confirmed that 20 genes positively contributed to prognosis prediction, displaying an area under the validation curve with a value of 0.89. In the corresponding OS analysis, all patients with SDH, STAT3 and PDCD1LG2 mutations were in the poor prognosis cohort (15/15, 100%). Analysis of public databases further confirms that SDH mutations are significantly associated with worse OS.

CONCLUSION

Our results provide a potential stratification of chemotherapy prognosis in SCLC patients, and have certain guiding significance for subsequent precise targeted therapy.

Comparative expression analysis of immune-related markers in surgically resected lung neuroendocrine neoplasms

BACKGROUND

Although immunotherapy has led to a paradigm shift in the treatment of lung cancer, the therapeutic approaches for lung neuroendocrine neoplasms (LNENs) are still limited. Our aim was to explore the immunological landscape and the expression of immune checkpoint markers in LNENs.

METHODS

Surgically removed tumor samples of 26 atypical carcinoid (AC), 30 large cell neuroendocrine carcinoma (LCNEC) and 29 small cell lung cancer (SCLC) patients were included. The immune phenotype of each tumor type was assessed by using a panel of 15 immune-related markers. As these markers are potentially expressed by immune cells and/or tumor cells, they might serve as putative targets for immunotherapy. Expression patterns were measured by immunohistochemistry and correlated with clinicopathological parameters and prognosis.

RESULTS

Unsupervised hierarchical clustering revealed distinct immunologic profiles across tumor types. Specifically, AC tumors were characterized by high tumor cell CD40 expression and low levels of immune infiltrates whereas SCLC samples had a high CD47 and Inducible T Cell Costimulator (ICOS) expression in tumor cells and immune cells, respectively. High CD70 and CD137 expression by tumor cells as well as elevated expression of CD27, Lymphocyte Activation Gene 3 (LAG3), and CD40 by immune cells were characteristic for LCNEC samples. Overall, SCLC and LCNEC tumors had a more immunogenic phenotype than AC samples. High tumor cell CD47 and CD40 expressions were associated with impaired and improved survival outcomes, respectively.

CONCLUSIONS

By providing insights into the widely divergent immunologic profiles of LNENs, our results might serve as a basis for the development of novel immunotherapy-related approaches in these devastating malignancies.

Spotlight on Small-Cell Lung Cancer and Other Lung Neuroendocrine Neoplasms

Lung neuroendocrine neoplasms (NENs) encompass a spectrum of neoplasms that are subdivided into the well-differentiated neuroendocrine tumors comprising the low- and intermediate-grade typical and atypical carcinoids, respectively, and the poorly differentiated, high-grade neuroendocrine carcinomas including large-cell neuroendocrine carcinomas and small-cell lung carcinoma (SCLC). Here, we review the current morphological and molecular classifications of the NENs on the basis of the updated WHO Classification of Thoracic Tumors and discuss the emerging subclassifications on the basis of molecular profiling and the potential therapeutic implications. We focus on the efforts in subtyping SCLC, a particularly aggressive tumor with few treatment options, and the recent advances in therapy with the adoption of immune checkpoint inhibitors in the frontline setting for patients with extensive-stage SCLC. We further highlight the promising immunotherapy strategies in SCLC that are currently under investigation.

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.