Comprehensive genomic profiling of combined small cell lung cancer

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Proteogenomic characterization of small cell lung cancer identifies biological insights and subtype-specific therapeutic strategies

We performed comprehensive proteogenomic characterization of small cell lung cancer (SCLC) using paired tumors and adjacent lung tissues from 112 treatment-naive patients who underwent surgical resection. Integrated multi-omics analysis illustrated cancer biology downstream of genetic aberrations and highlighted oncogenic roles of FAT1 mutation, RB1 deletion, and chromosome 5q loss. Two prognostic biomarkers, HMGB3 and CASP10, were identified. Overexpression of HMGB3 promoted SCLC cell migration via transcriptional regulation of cell junction-related genes. Immune landscape characterization revealed an association between ZFHX3 mutation and high immune infiltration and underscored a potential immunosuppressive role of elevated DNA damage response activity via inhibition of the cGAS-STING pathway. Multi-omics clustering identified four subtypes with subtype-specific therapeutic vulnerabilities. Cell line and patient-derived xenograft-based drug tests validated the specific therapeutic responses predicted by multi-omics subtyping. This study provides a valuable resource as well as insights to better understand SCLC biology and improve clinical practice.

Sustained Clinical Response to 4th-Line Therapy with Selpercatinib in RET Fusion-Positive Combined Small Cell Lung Cancer

Objective

Combined small cell lung cancer (C-SCLC) is a relatively rare subtype of small cell lung cancer (SCLC) which combines SCLC and any component of non-small cell carcinoma (NSCLC). Patients diagnosed with C-SCLC are currently recommended to receive the same treatment as SCLC cases in the absence of clear evidence suggesting different strategies. The genomic profiling of C-SCLC is rarely studied. Herein, we report a case of extensive-stage C-SCLC harboring the KIF5B-RET fusion before first-line therapy and with persistent sensitivity to fourth-line selpercatinib treatment is reported.

Materials and Methods

Molecular and pathological features were evaluated using transbronchial lung biopsy, immunohistochemical (IHC) staining and next-generation sequencing (NGS).

Results

NGS revealed the KIF5B-RET fusion in the C-SCLC tumor. The patient had a progression-free survival (PFS) surpassing 14 months after selpercatinib treatment, with ongoing clinical response in 4th-line treatment.

Conclusion

This case highlights the importance of comprehensive molecular testing in C-SCLC for selecting the optimal treatment. Although RET fusion is rare in patients with C-SCLC, its identification and treatment with selective RET inhibitors may contribute to clinical benefits.

Combined small cell lung cancer: current progress and unmet needs

Combined small cell lung cancer (CSCLC) is a specific subtype of lung cancer characterized by a pathological mixture of small cell lung cancer and any subtype of non-small cell lung cancer components. Currently, our understanding of the clinicopathological features, origin, molecular characterization, treatment, and prognosis of CSCLC remains limited. CSCLCs represent examples of intratumor heterogeneity and pose challenges for accurate diagnosis. Are there any distinct clinicopathologic and molecular differences between pure SCLC and CSCLC? Furthermore, the prognostic outcomes and optimal treatments for CSCLC are urgently needed. This article aims to summarize the current biological features and clinical management of CSCLC, providing a reference for further understanding of this heterogeneous form of small cell lung cancer.

Clinicopathological and Treatment Patterns of Combined Small-Cell Lung Carcinoma with Future Insight to Treatment: A Population-Based Study

BACKGROUND

Primary lung cancer is the most common cause of cancer-related mortality in the United States (US). Approximately 90% of lung cancers are associated with smoking and the use of other tobacco products. Based on histology, lung cancers are divided into small-cell lung carcinomas (SCLCs) and non-small-cell lung carcinomas (NSCLCs). Most SCLCs are of the pure subtype, while the rare combined SCLCs contain elements of both small-cell and non-small-cell morphologies. This study sought to evaluate the demographics, clinical factors, molecular abnormalities, treatment approaches, and survival outcomes with combined SCLC and NSCLCs.

MATERIALS AND METHODS

Data on 2126 combined SCLC patients was extracted from the Surveillance Epidemiology and End Result (SEER) database from 2000 to 2018. Data extracted for analyses included age, sex, race, tumor size, tumor location, metastasis status, stage at diagnosis, treatment received, and treatment outcomes. Multivariate analysis was performed using Statistical Product and Service Solutions (SPSS) software.

RESULTS

The patients had a median age of 68 years; 43.9% of the patients were female and 56.1% were male; 84.5% were White and 11.7% were African Americans. The majority of patients had a poorly differentiated disease at 29.6%; 17% were undifferentiated, 3.2% were moderately differentiated, and 0.8% were well differentiated. Chemotherapy was the most common treatment modality (45.3%); 17% underwent surgery only, 10.3% underwent surgery followed by adjuvant chemotherapy, and 10% underwent radiation after surgery. Five-year cancer-specific survival was 15.2% with surgery alone, and combined surgery and chemotherapy provided the highest percentages (38.3% and 34.7%, respectively). Females had significantly higher 1- and 5-year cancer-specific survival rates compared to males (59.3% and 29.9% vs. 48.0% and 23.7, respectively; p < 0.001). Well-differentiated tumors had significantly higher survival compared to other gradings (p < 0.001). Survival decreased as tumor staging moved distally from localized to regional to distant (p < 0.001). Metastasis to bone, liver, brain, and lung significantly decreased survival in comparison to patients who did not have any metastasis (p < 0.001). Females had significantly shorter survival compared to their counterparts when metastasis was to the bone, brain, or liver (p < 0.001). Multivariate analysis identified male sex (Hazard Ratio (HR) = 1.2), undifferentiated grade (HR = 1.9), regional extent of disease (HR = 1.7), distant extent of disease (HR = 3.7), and metastasis to liver (HR = 3.5) as variables associated with worse survival.

CONCLUSION

Combined SCLC is overall very rare. However, the frequency of presentation with combined SCLC is on the rise, in part due to improvements in diagnostic techniques. Despite advances in therapies, treating combined SCLC is challenging, and novel therapies are not utilized, owing to low rates of targetable mutations. Combined SCLC has higher survival rates if well differentiated.

A case report of pulmonary combined small cell carcinoma with enteric adenocarcinoma

Background

Combined small cell lung cancer (CSCLC) is rarely reported, which accounting for only 2% to 5% of all lung cancers. And enteric adenocarcinoma is also a rare subtype of non-small cell lung cancer (NSCLC) whose histomorphology is very similar to lung metastatic colorectal cancer.

Case Description

We report a case with both small cell lung cancer (SCLC) and enteric adenocarcinoma for the first time. The patient was admitted to our hospital due to the left lung mass after a routine examination. She underwent computed tomography scan and needle biopsy, which showed the tumor consisted of two different components (70% SCLC and 30% enteric adenocarcinoma). The mixed density nodules were also observed in the right lung's lower lobe, and positron emission tomography-computed tomography (PET-CT) showed an increase of standard uptake value (SUV) greater than 2.5 in the right lung. Imaging and pathology experts agreed that the nodules of right lung were metastatic lesions after multi-disciplinary treatment (MDT). Considering the epidermal growth factor receptor (EGFR) p.L861Q mutation, the patient received gefitinib and EP chemotherapy, and she responded well to the combination therapy. At last follow-up, the progression-free survival (PFS) reached 11 months, and the adverse effects were clinically acceptable and tolerable.

Conclusions

This case report provides direct evidence for EGFR-tyrosine kinase inhibitor (TKI) and EP chemotherapy is effective and useful in the treatment of CSCLC patients with enteric adenocarcinoma.

Efficacy evaluation of surgery combined with chemotherapy for stage IIIA small cell lung cancer patients: a retrospective analysis

Background

The efficacy of surgery in combination of chemotherapy for stage IIIA small cell lung cancer (IIIA-SCLC) is controversial. The aim of the present study was to analyze the efficacy of surgery combined with chemotherapy, especially in the setting of neoadjuvant chemotherapy (NAC) followed by surgery for IIIA-SCLC.

Methods

Between 2004 and 2015, we reviewed 2,199 chemotherapy-treated stage IIIA (N1/2) SCLC cases in the Surveillance, Epidemiology, and End Results (SEER) database, and 32 NAC + intentional radical resection-treated, centrally-located IIIA-SCLC cases at Shanghai Pulmonary Hospital (SPH). Outcomes were compared between surgically and non-surgically treated patients from the SEER database after propensity score matching (PSM), and comparing lobectomy/bi-lobectomy and pneumonectomy patients from SPH. Prognostic factors were evaluated by Kaplan-Meier method and the Cox proportional hazards regression model.

Results

There was significantly higher overall survival (OS) in surgically treated IIIA-SCLC patients (OS, 44.8 vs. 21.2 months, P=0.048), and similar efficacy was observed between sub-lobectomy and lobectomy/bi-lobectomy patients (OS: 55.6 vs. 30.3 months, P=0.167) in SEER database. At SPH, significantly higher OS was associated with T1 stage (before NAC: T1 vs. T2-4, 48.7 vs. 32.2 months, P=0.025; after NAC: T1 vs. T2-4, 42.7 vs. 21.3 months, P=0.048). Female sex [hazard ratio (HR): 0.078, P=0.009], T1 stage (HR: 13.048, P=0.026), and pneumonectomy (HR: 0.095, P=0.009) were independent prognostic factors for IIIA-SCLC patients who received NAC + intentional radical resection.

Conclusions

For stage IIIA SCLC patients, complete resection combined with chemotherapy might improve the prognosis than patients without surgery. Post-NAC lobectomy was not found to be superior to sub-lobectomy, while pneumonectomy was considered suitable for central-type IIIA-SCLC patients after NAC treatment.

Integrative molecular analysis of combined small-cell lung carcinomas identifies major subtypes with different therapeutic opportunities

BACKGROUND

Combined small-cell lung cancer (C-SCLC) is composed of SCLC admixed with a non-small-cell cancer component. They currently receive the same treatment as SCLC. The recent evidence that SCLC may belong to either of two lineages, neuroendocrine (NE) or non-NE, with different vulnerability to specific cell death pathways such as ferroptosis, opens new therapeutic opportunities also for C-SCLC.

MATERIALS AND METHODS

Thirteen C-SCLCs, including five with adenocarcinoma (CoADC), five with large-cell neuroendocrine carcinoma (CoLCNEC) and three with squamous cell carcinoma (CoSQC) components, were assessed for alterations in 409 genes and transcriptomic profiling of 20 815 genes.

RESULTS

All 13 cases harbored TP53 (12 cases) and/or RB1 (7 cases) inactivation, which was accompanied by mutated KRAS in 4 and PTEN in 3 cases. Potentially targetable alterations included two KRAS G12C, two PIK3CA and one EGFR mutations. Comparison of C-SCLC transcriptomes with those of 57 pure histology lung cancers (17 ADCs, 20 SQCs, 11 LCNECs, 9 SCLCs) showed that CoLCNEC and CoADC constituted a standalone group of NE tumors, while CoSQC transcriptional setup was overlapping that of pure SQC. Using transcriptional signatures of NE versus non-NE SCLC as classifier, CoLCNEC was clearly NE while CoSQC was strongly non-NE and CoADC exhibited a heterogeneous phenotype. Similarly, using ferroptosis sensitivity/resistance markers, CoSQC was classified as sensitive (as expected for non-NE), CoLCNEC as resistant (as expected for NE) and CoADC showed a heterogeneous pattern.

CONCLUSIONS

These data support routine molecular profiling of C-SCLC to search for targetable driver alterations and to precisely classify them according to therapeutically relevant subgroups (e.g. NE versus non-NE).

Clinical features and prognostic factors of combined small cell lung cancer: development and validation of a nomogram based on the SEER database

Background

Combined small-cell lung cancer (CSCLC) refers to the simultaneous presence of small cell lung cancer (SCLC) and any subtype of the non-small cell lung cancer (NSCLC). This study aimed to explore the prognosis of CSCLC, NSCLC, and pure SCLC patients, and to develop a nomogram to estimate the overall survival (OS) for CSCLC patients.

Methods

Patients diagnosed with NSCLC, CSCLC, and pure SCLC between 2004 and 2015 were identified from the Surveillance Epidemiology and End Results (SEER) database. Survival analyses were performed by using the Kaplan Meier curves and Cox proportional hazards regression. All CSCLC patients were randomly split 7:3 into training and validation sets. A nomogram was developed by integrating all independent predictors for OS. The performance of the nomogram was determined by discrimination, calibration ability, clinical usefulness, and risk stratification ability.

Results

A total of 326,695 lung cancer patients, including 871 with CSCLC, 280,391 with NSCLC, and 45,433 with pure SCLC were enrolled. CSCLC was associated with worse survival compared with NSCLC both in the unmatched and matched cohorts. However, compared to pure SCLC, CSCLC was associated with significantly better survival in the unmatched cohorts only, while showed marginally non-significantly better survival after propensity score matching (PSM). For CSCLC, a nomogram was constructed for the 6-month, 1-year, and 3-year OS prediction by combining the independent risk factors, including age, gender, tumor, node, and metastasis stage, surgery, and chemotherapy. The nomogram showed good discrimination and calibration both in the training and validation sets, and better performance than the tumor-node-metastasis staging system. Risk stratification analysis indicated that the nomogram scores efficiently divided CSCLC patients into low-, intermediate-, and high-risk groups (P<0.001).

Conclusions

CSCLC patients presented a significantly worse prognosis than patients with NSCLC, but comparable prognosis when compared with pure SCLC patients in the matched cohorts. In addition, we developed and validated a nomogram for predicting the 6-month, 1-year, and 3-year OS in CSCLC patients.

Comprehensive analysis of prognostic predictors for patients with limited-stage small-cell lung cancer who underwent resection followed by adjuvant chemotherapy

Background

The prognosis of patients with limited-stage small-cell lung cancer (LS-SCLC) who undergo resection followed by adjuvant chemotherapy (ACT) is uncertain. Thus, we combined clinicopathological characteristics and next-generation sequencing (NGS) to answer this question.

Methods

In total, the data of 51 LS-SCLC patients who had undergone complete surgical resection and postoperative ACT were retrospectively collected. NGS examinations with a 68-gene panel were performed for each specimen. Patients' genetic status and potentially clinical correlations were statistically evaluated. Progression-free survival (PFS) and overall survival (OS) were plotted using Kaplan-Meier curves. The independent prognostic factors for the primary cohort were investigated using univariable and multivariable cox proportional hazard regression analyses. Subgroup analyses were also conducted based on retinoblastoma protein 1 (RB1) status.

Results

Combined SCLC (c-SCLC) had similar clinical and pathological characteristics to that of pure SCLC (p-SCLC). TP53 and RB1 were 2 major genetic mutations present in both p-SCLC and c-SCLC. c-SCLC had a unique genetic profile that was related to the PI3K/AKT/mTOR and WNT/β-catenin signaling pathways. There was no prognostic difference between c-SCLC and p-SCLC. However, the pathological node (N) stage of lymphovascular invasion (LVI), which was related to PFS and age, corelated with OS. Neither pathological subtypes nor genetic mutations affected the survival outcomes. Notably, RB1 mutated c-SCLC resulted in poorer DFS compared to that of p-SCLC among LS-SCLC patients who underwent resection followed by ACT.

Conclusions

Our examination of LS-SCLC patients who underwent resection followed by ACT showed that c-SCLC and p-SCLC had a clinical and prognostic similarity and a genetic peculiarity. Thus, it is essential that a new classification system be proposed for SCLC. Such a system is especially needed for LS-SCLC.