Patient-derived tumoroid models of pulmonary large-cell neuroendocrine carcinoma: a promising tool for personalized medicine and developing novel therapeutic strategies.

Pulmonary large-cell neuroendocrine carcinoma (LCNEC), a disease with poor prognosis, is classified as pulmonary high-grade neuroendocrine carcinoma, along with small-cell lung cancer. However, given its infrequent occurrence, only a limited number of preclinical models have been established. Here, we established three LCNEC tumoroids for long-term culture. Whole-exome sequencing revealed that these tumoroids inherited genetic mutations from their parental tumors; two were classified as small-cell carcinoma (S-LCNEC) and one as non-small cell carcinoma (N-LCNEC). Xenografts from these tumoroids in immunodeficient mice mimicked the pathology of the parent LCNEC, and one reproduced the mixed-tissue types of combined LCNEC with a component of adenocarcinoma. Drug sensitivity tests using these LCNEC tumoroids enabled the evaluation of therapeutic agent efficacy. Based on translational research, we found that a CDK4/6 inhibitor might be effective for N-LCNEC and that Aurora A kinase inhibitors might be suitable for S-LCNEC or LCNEC with MYC amplification. These results highlight the value of preclinical tumoroid models in understanding the pathogenesis of rare cancers and developing treatments. LCNEC showed a high success rate in tumoroid establishment, indicating its potential application in personalized medicine.

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.

An in-silico analysis reveals further evidence of an aggressive subset of lung carcinoids sharing molecular features of high-grade neuroendocrine neoplasms.

Little is known as to whether there may be any pathogenetic link between pulmonary carcinoids and neuroendocrine carcinomas (NECs). A gene signature we previously found to cluster pulmonary carcinoids, large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC), and which encompassed MEN1, MYC, MYCL1, RICTOR, RB1, SDHA, SRC and TP53 mutations or copy number variations (CNVs), was used to reclassify an independent cohort of 54 neuroendocrine neoplasms (NENs) [31 typical carcinoids (TC), 11 atypical carcinoids (AC) and 12 SCLC], by means of transcriptome and mutation data. Unsupervised clustering analysis identified two histology-independent clusters, namely CL1 and CL2, where 17/42 (40.5%) carcinoids and all the SCLC samples fell into the latter. CL2 carcinoids affected survival adversely, were enriched in T to G transversions or T > C/C > T transitions in the context of specific mutational signatures, presented with at least 1.5-fold change (FC) increase of gene mutations including TSC2, SMARCA2, SMARCA4, ERBB4 and PTPRZ1, differed for gene expression and showed epigenetic changes in charge of MYC and MTORC1 pathways, cellular senescence, inflammation, high-plasticity cell state and immune system exhaustion. Similar results were also found in two other independent validation sets comprising 101 lung NENs (24 carcinoids, 21 SCLC and 56 LCNEC) and 30 carcinoids, respectively. We herein confirmed an unexpected sharing of molecular traits along the spectrum of lung NENs, with a subset of genomically distinct aggressive carcinoids sharing molecular features of high-grade neuroendocrine neoplasms.

Real-World comprehensive genomic profiling data for diagnostic clarity in pulmonary Large-Cell neuroendocrine carcinoma.

BACKGROUND: Pulmonary large-cell neuroendocrine carcinoma (LCNEC) is an uncommon subtype of lung cancer believed to represent a spectrum of tumors sharing characteristics of both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Other groups have proposed genomic LCNEC subtypes, including small cell-like, non-small cell-like, and carcinoid-like subtypes. The primary goal of this study was to better define the NSCLC-like subtype with comprehensive genomic profiling (CGP). METHODS: An institutional database was queried to identify tissue specimens (TBx, N = 1,426) and liquid biopsies (LBx, N = 39) submitted for CGP during routine clinical care (8/2014 - 7/2023) with a disease ontology of LCNEC. TBx were profiled with FoundationOne® (F1) or F1CDx, using hybrid-capture technology to detect genomic alterations (GAs). RESULTS: 1,426 LCNEC samples were genomically profiled. The presence of RB1 and TP53 genomic alterations (GAs) were used to define a SCLC-like subtype (n = 557). A carcinoid-like group was defined by the presence of MEN1 mutation in the absence of TP53 GAs (n = 25). The remaining 844 samples were compared to the SCLC-like group and GAs enriched relative to the SCLC-like samples with a false discovery rate (FDR) < 0.0001 were used to define a NSCLC-like group. These NSCLC-like subtype-defining GAs included SMARCA4, KRAS, FGF3/4/19, STK11, CDKN2A/B, MTAP, and CCND1. Under this schema, 530 samples were classified as NSCLC-like and 314 remained unclassified. CONCLUSIONS: Large-scale CGP can better characterize biologically distinct molecular subtypes in LCNEC. Further studies to define how these molecular subtypes may help inform treatment decisions in this complex and challenging malignancy are warranted.

Novel Mouse Cell Lines and In Vivo Models for Human High-Grade Neuroendocrine Lung Carcinoma, Small Cell Lung Carcinoma (SCLC), and Large Cell Neuroendocrine Carcinoma (LCNEC).

There is a clear need to expand the toolkit of adequate mouse models and cell lines available for preclinical studies of high-grade neuroendocrine lung carcinoma (small cell lung carcinoma (SCLC) and large cell neuroendocrine carcinoma (LCNEC)). SCLC and LCNEC are two highly aggressive tumor types with dismal prognoses and few therapeutic options. Currently, there is an extreme paucity of material, particularly in the case of LCNEC. Given the lack of murine cell lines and transplant models of LCNEC, the need is imperative. In this study, we generated and examined new models of LCNEC and SCLC transplantable cell lines derived from our previously developed primary mouse LCNEC and SCLC tumors. RNA-seq analysis demonstrated that our cell lines and syngeneic tumors maintained the transcriptome program from the original transgenic primary tumor and displayed strong similarities to human SCLC or LCNEC. Importantly, the SCLC transplanted cell lines showed the ability to metastasize and mimic this characteristic of the human condition. In summary, we generated mouse cell line tools that allow further basic and translational research as well as preclinical testing of new treatment strategies for SCLC and LCNEC. These tools retain important features of their human counterparts and address the lack of LCNEC disease models.

Exploring the molecular features and genetic prognostic factors of pulmonary high-grade neuroendocrine carcinomas.

Molecular research on large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC) has progressed significantly. However, there are still fewer molecular markers related to prognostic/therapeutic strategies for these conditions compared to those for adenocarcinoma. We therefore investigated the molecular characteristics of neuroendocrine carcinomas (NECs). We enrolled patients surgically diagnosed with NECs between 2011 and 2019, with complete follow-up records. All were analyzed using whole exome sequencing and p53/Rb immunohistochemistry (IHC). A total of 92 cases, comprising 45 pure SCLC, 15 combined SCLC, 27 pure LCNEC, and 5 combined LCNEC, were included. TP53 (78.3%) and RB1 (34.8%) were the most common molecular alterations, followed by KMT2D, LRP1B, FAT3, NCOR2, SPTA1, and NOTCH1. The mutation frequency for EGFR was 10.9%. Sixteen patients with LCNEC who had TP53/RB1 co-alterations were SCLC-like, while the remaining were NSCLC-like. There was no statistically significant difference between the groups regarding overall survival (OS; p = 0.458) and progression-free survival (PFS; p = 0.157). The frequency of the loss of Rb expression by IHC in SCLC-like LCNEC was 100%. Significant pathway alterations unique to SCLC included Notch and AMPK, while HIF-1 was enriched exclusively in LCNEC. NCOR2 mutation was linked to worse OS (p = 0.029) and PFS (p = 0.015), while wild-type SPTA1 was associated with poor PFS (p = 0.018). IHC for Rb was reliable for predicting LCNEC molecular subtypes, indicating its clinical value. NCOR2 and SPTA1 alterations were identified as prognostic factors that may provide therapeutic targets for patients with NEC.

[Large cell carcinoma of the lung with null immunophenotype: Case report & brief review]. / Carcinoma de células grandes de pulmón con inmunofenotipo nulo: reporte de caso y revisión breve de la literatura.

Large cell carcinoma of the lung with null-immunophenotype (LCC-NI) is a diagnostic entity that is especially uncommon now as it does not have any type of cell differentiation or its own molecular alterations. It presents an exceptional diagnostic challenge; indeed, the diagnosis is only possible with complete surgical excision and adequate immunohistochemical and molecular studies. We report the case of a 69-year-old male, with a history of long-term smoking who presented with pleuritic pain. A tumor in the upper lobe of the right lung was detected and removed by lobectomy. Histopathology revealed a neoplasm with large cell morphology without any specific immunophenotype, molecular or genomic rearrangements through next-generation sequencing (NGS) studies, which was diagnosed as LCC-NI.

[Alectinib and mixed large cell neuroendocrine carcinoma of the lung.] / Az alectinib és a tüdo kevert nagysejtes neuroendokrin carcinomája.

The treatment of mixed large cell neuroendocrine carcinoma is less studied due to its low incidence. However, the presence of anaplastic lymphoma kinase (ALK) fusion gene is rare in such tumours, ALK inhibitors may represent a promising therapeutic option instead of cytostatic therapy. Routine chest X-ray and then computed tomography (CT) examination revealed a pulmonary tumour in a 52-year-old asymptomatic woman. The neoplasm was removed by lobectomy. Histological examination confirmed papillary predominant lung adenocarcinoma. The patient was treated with postoperative chemotherapy and irradiation. 3 years later, neurologic symptoms were observed, therefore, brain CT was performed. The evaluation confirmed brain metastases which were removed. Histological examination identified metastasis of large cell neuroendocrine carcinoma. Revision and molecular examination of the metastasis and lung specimen revealed pulmonary mixed large cell neuroendocrine carcinoma with ALK-rearrangement. Alectinib (Alecensa) treatment was initiated resulting in regression of the previously observed liver metastases. Progression has not occurred in the last 3 years since the start of treatment. Detection of ALK fusion genes and research of ALK inhibitor therapy focus primarily on lung adenocarcinomas. Our case report would like to draw attention to the evaluation of driver mutations in pulmonary mixed neuroendocrine carcinoma with adenocarcinoma component because targeted treatment may be an effective alternative. Orv Hetil. 2023; 164(14): 548-554.

Comparative study of the genomic landscape and tumor microenvironment among large cell carcinoma of the lung, large cell neuroendocrine of the lung, and small cell lung cancer.

Deciphering the genomic profiles and tumor microenvironment (TME) in large cell carcinomas of the lung (LCC), large cell neuroendocrine of the lung (LCNEC), and small cell lung cancer (SCLC) might contribute to a better understanding of lung cancer and then improve outcomes. Ten LCC patients, 12 LCNEC patients, and 18 SCLC patients were enrolled. Targeted next-generation sequencing was used to investigate the genomic profiles of LCC, LCNEC, and SCLC. Tumor-infiltrating lymphocytes (TILs) within cancer cell nests and in cancer stroma were counted separately. Precise 60% of LCNEC patients harbored classical non-small cell lung cancer driver alterations, occurring in BRAF, KRAS, ROS1, and RET. More than 70% of SCLC patients harbored TP53-RB1 co-alterations. Moreover, 88.9%, 40%, and 77.8% of LCC, LCNEC, and SCLC cases had a high tumor mutation burden level with more than 7 mutations/Mb. Furthermore, high index of CD68+ CD163+ (TILs within cancer cell nests/ TILs within cancer cell nests and in cancer stroma, P = .041, 548 days vs not reached) and CD163+ TILs (P = .041, 548 days vs not reached) predicted a shorter OS in SCLC. Our findings revealed the distinct genomic profiles and TME contexture among LCC, LCNEC, and SCLC. Our findings suggest that stratifying LCNEC/SCLC patients based on TME contexture might help clinical disease management.

Pulmonary Combined Large Cell Neuroendocrine Carcinoma.

Pulmonary combined large-cell neuroendocrine carcinoma (CLCNEC) is a rare neuroendocrine tumor pertained to lung large cell neuroendocrine carcinoma (LCNEC) with aggressive behavior and poor prognosis generally. The clinical features of CLCNEC are not specific including cough, expectoration, chest distress, chest pain, etc., which are prone to have different manifestations of the mixed components. Owing to the low incidence, there are few related small-scale retrospective studies and case reports. Currently, the treatment regimen of CLCNEC mainly refers to LCNEC that complete surgical resection is preferred in the early stage and according to previous researches, platinum-based small cell lung cancer (SCLC) standard treatment regimen showed promising results in postoperative and advanced CLCNEC as compared to that of non-small cell lung cancer (NSCLC). Adenocarcinoma-CLCNEC more likely harbor driver gene mutation, and may benefit from targeted therapy. As for immunotherapy, more clinical trial data are needed to support its benefits. This article will fill the gap and will provide new insight into the clinical characteristics, pathological diagnosis and treatment endeavors of CLCNEC.

Pulmonary cancers across different histotypes share hybrid tuft cell/ionocyte-like molecular features and potentially druggable vulnerabilities.

Tuft cells are chemosensory epithelial cells in the respiratory tract and several other organs. Recent studies revealed tuft cell-like gene expression signatures in some pulmonary adenocarcinomas, squamous cell carcinomas (SQCC), small cell carcinomas (SCLC), and large cell neuroendocrine carcinomas (LCNEC). Identification of their similarities could inform shared druggable vulnerabilities. Clinicopathological features of tuft cell-like (tcl) subsets in various lung cancer histotypes were studied in two independent tumor cohorts using immunohistochemistry (n = 674 and 70). Findings were confirmed, and additional characteristics were explored using public datasets (RNA seq and immunohistochemical data) (n = 555). Drug susceptibilities of tuft cell-like SCLC cell lines were also investigated. By immunohistochemistry, 10-20% of SCLC and LCNEC, and approximately 2% of SQCC expressed POU2F3, the master regulator of tuft cells. These tuft cell-like tumors exhibited "lineage ambiguity" as they co-expressed NCAM1, a marker for neuroendocrine differentiation, and KRT5, a marker for squamous differentiation. In addition, tuft cell-like tumors co-expressed BCL2 and KIT, and tuft cell-like SCLC and LCNEC, but not SQCC, also highly expressed MYC. Data from public datasets confirmed these features and revealed that tuft cell-like SCLC and LCNEC co-clustered on hierarchical clustering. Furthermore, only tuft cell-like subsets among pulmonary cancers significantly expressed FOXI1, the master regulator of ionocytes, suggesting their bidirectional but immature differentiation status. Clinically, tuft cell-like SCLC and LCNEC had a similar prognosis. Experimentally, tuft cell-like SCLC cell lines were susceptible to PARP and BCL2 co-inhibition, indicating synergistic effects. Taken together, pulmonary tuft cell-like cancers maintain histotype-related clinicopathologic characteristics despite overlapping unique molecular features. From a therapeutic perspective, identification of tuft cell-like LCNECs might be crucial given their close kinship with tuft cell-like SCLC.

Diagnostic criteria and evolving molecular characterisation of pulmonary neuroendocrine carcinomas.

Neuroendocrine carcinomas of the lung are currently classified into two categories: small-cell lung carcinoma and large-cell neuroendocrine carcinoma. Diagnostic criteria for small-cell and large-cell neuroendocrine carcinoma are based solely on tumour morphology; however, overlap in histologic and immunophenotypic features between the two types of carcinomas can potentially make their classification challenging. Accurate diagnosis of pulmonary neuroendocrine carcinomas is paramount for patient management, as clinical course and treatment differ between small-cell and large-cell neuroendocrine carcinoma. Molecular-genetic, transcriptomic, and proteomic data published over the past decade suggest that small-cell and large-cell neuroendocrine carcinomas are not homogeneous categories but rather comprise multiple groups of distinctive malignancies. Nuances in the susceptibility of small-cell lung carcinoma subtypes to different chemotherapeutic regimens and the discovery of targetable mutations in large-cell neuroendocrine carcinoma suggest that classification and treatment of neuroendocrine carcinomas may be informed by ancillary molecular and protein expression testing going forward. This review summarizes the current diagnostic criteria, prognostic and predictive correlates of classification, and evidence of previously unrecognised subtypes of small-cell and large-cell neuroendocrine carcinoma.

Different Characteristics and Survival between Surgically Resected Pure and Combined Pulmonary Large Cell Neuroendocrine Carcinoma.

BACKGROUND: Large cell neuroendocrine carcinoma (LCNEC) is a rare high-grade neuroendocrine carcinoma of the lung. Little is known about the differences between the pure and combined LCNEC subtypes, and thus we conducted this study to provide more comprehensive insight into LCNEC. METHODS: We reviewed 221 patients with pure LCNEC (P-LCNEC) and 120 patients with combined LCNEC (C-LCNEC) who underwent pulmonary surgery in our hospital to compare their clinical features, driven genes' status (EGFR/ALK/ROS1/KRAS/BRAF), and adjuvant chemotherapy regimens. Propensity score matching (PSM) was applied to reduce selection bias. RESULTS: The P-LCNEC group included a higher proportion of males and smokers than the C-LCNEC group. Furthermore, the C-LCNEC group had higher incidences of visceral pleural invasion (VPI), EGFR mutation and ALK rearrangement compared with the P-LCNEC group. Expression of neuroendocrine markers (CD56, CGA, and SYN) and recurrence patterns were not significantly different between the two groups. The P-LCNEC group had better disease-free survival (DFS) and overall survival (OS) compared with the C-LCNEC group (median DFS: 67.0 vs. 28.1 months, p = 0.021; median OS: 72.0 vs. 45.0 months, p = 0.001), which was further confirmed by the PSM method (p = 0.004 and p < 0.001, respectively). Adjuvant chemotherapy was also an independent factor for DFS and OS. Subgroup analysis found that regardless of whether it was for the entire LCNEC group or the P- and C-LCNEC subtypes, the small cell lung cancer (SCLC) regimens presented with superior survival compared with the non-small cell lung cancer (NSCLC) regimens. CONCLUSION: P-LCNEC was associated with more favorable prognosis compared with C-LCNEC. SCLC-based adjuvant chemotherapy was more appropriate for LCNEC patients than NSCLC-based regimens, regardless of whether they were the pure or combined LCNEC subtypes. C-LCNEC patients may be the potential beneficiary of targeted therapy.

Comprehensive Characterization of the Genomic Landscape in Chinese Pulmonary Neuroendocrine Tumors Reveals Prognostic and Therapeutic Markers (CSWOG-1901).

BACKGROUND: Pulmonary neuroendocrine tumors (pNETs) include typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell lung carcinoma (SCLC). The optimal treatment strategy for each subtype remains elusive, partly due to the lack of comprehensive understanding of their molecular features. We aimed to explore differential genomic signatures in pNET subtypes and identify potential prognostic and therapeutic biomarkers. METHODS: We investigated genomic profiles of 57 LCNECs, 49 SCLCs, 18 TCs, and 24 ACs by sequencing tumor tissues with a 520-gene panel and explored the associations between genomic features and prognosis. RESULTS: Both LCNEC and SCLC displayed higher mutation rates for TP53, PRKDC, SPTA1, NOTCH1, NOTCH2, and PTPRD than TC and AC. Small cell lung carcinoma harbored more frequent co-alterations in TP53-RB1, alterations in PIK3CA and SOX2, and mutations in HIF-1, VEGF and Notch pathways. Large cell neuroendocrine carcinoma (12.7 mutations/Mb) and SCLC (11.9 mutations/Mb) showed higher tumor mutational burdens than TC (2.4 mutations/Mb) and AC (7.1 mutations/Mb). 26.3% of LCNECs and 20.8% of ACs harbored alterations in classical non-small cell lung cancer driver genes. The presence of alterations in the homologous recombination pathway predicted longer progression-free survival in advanced LCNEC patients with systemic therapy (P = .005) and longer overall survival (OS) in SCLC patients with resection (P = .011). The presence of alterations in VEGF (P = .048) and estrogen (P = .018) signaling pathways both correlated with better OS in patients with resected SCLC. CONCLUSION: We performed a comprehensive genomic investigation on 4 pNET subtypes in the Chinese population. Our data revealed distinctive genomic signatures in subtypes and provided new insights into the prognostic and therapeutic stratification of pNETs.

Genetic and immunohistochemical profiling of small cell and large cell neuroendocrine carcinomas of the breast.

Neuroendocrine carcinomas (NEC) of the breast are exceedingly rare tumors, which are classified in the WHO system as small cell (SCNEC) and large cell (LCNEC) carcinoma based on indistinguishable features from their lung counterparts. In contrast to lung and enteropancreatic NEC, the genomics of breast NEC have not been well-characterized. In this study, we examined the clinicopathologic, immunohistochemical, and genetic features of 13 breast NEC (7 SCNEC, 4 LCNEC, 2 NEC with ambiguous small versus large cell morphology [ANEC]). Co-alterations of TP53 and RB1 were identified in 86% (6/7) SCNEC, 100% (2/2) ANEC, and 50% (2/4) LCNEC. The one SCNEC without TP53/RB1 alteration had other p53 pathway aberrations (MDM2 and MDM4 amplification) and was immunohistochemically RB negative. PIK3CA/PTEN pathway alterations and ZNF703 amplifications were each identified in 46% (6/13) NEC. Two tumors (1 SCNEC, 1 LCNEC) were CDH1 mutated. By immunohistochemistry, 100% SCNEC (6/6) and ANEC (2/2) and 50% (2/4) LCNEC (83% NEC) showed RB loss, compared to 0% (0/8) grade 3 neuroendocrine tumors (NET) (p < 0.001) and 38% (36/95) grade 3 invasive ductal carcinomas of no special type (IDC-NST) (p = 0.004). NEC were also more often p53 aberrant (60% vs 0%, p = 0.013), ER negative (69% vs 0%, p = 0.005), and GATA3 negative (67% vs 0%, p = 0.013) than grade 3 NET. Two mixed NEC had IDC-NST components, and 69% (9/13) of tumors were associated with carcinoma in situ (6 neuroendocrine DCIS, 2 non-neuroendocrine DCIS, 1 non-neuroendocrine LCIS). NEC and IDC-NST components of mixed tumors were clonally related and immunophenotypically distinct, lacking ER and GATA3 expression in NEC relative to IDC-NST, with RB loss only in NEC of one ANEC. The findings provide insight into the pathogenesis of breast NEC, underscore their classification as a distinct tumor type, and highlight genetic similarities to extramammary NEC, including highly prevalent p53/RB pathway aberrations in SCNEC.

[Clinical and molecular pathological features of bronchopulmonary large cell neuroendocrine carcinoma].

Objective: To investigate the clinical manifestations, imaging, pathological and molecular features of bronchopulmonary large-cell neuroendocrine carcinoma (LCNEC). Methods: The clinical data of 216 LCNEC patients in the First Affiliated Hospital of Zhengzhou University from 2011 to 2021 were analyzed retrospectively. The clinical manifestations, tumor location and size, characteristics of CT images, immunohistochemical and molecular pathological features were analyzed and compared with 115 cases of mixed small cell carcinoma (M-SCLC) diagnosed in the same period. Results: Among the 216 LCNEC patients, there were 190 males and 26 females, with a median age of 65 years. The first symptoms of the patients were mainly cough (106 cases, 49.1%) and bloody sputum (48 cases, 22.2%). The median tumor length were 4.7cm, including 55 cases of nodular type (25.5%) and 161 cases of mass-forming type (74.5%). CT imaging results showed that LCNEC lesions had soft tissue density, and the proportion of slight enhancement lesions was significantly lower than that in M-SCLC group (52.3% vs 74.8%, P<0.001). In contrast, the proportion of necrosis (87.0% vs 58.3%, P<0.001) and calcification (26.9% vs 2.6%, P<0.001) in LCNEC patients was significantly higher than that in M-SCLC group. Immunohistochemical results showed that the positive rate of CK in LCNEC was significantly higher than that in M-SCLC (99.0 % vs 90.5%, P<0.05), while the positive rate of TTF-1 was significantly lower than that in M-SCLC (51.6% vs 67.0%, P<0.05). In LCNEC group, the proportion of patients with Ki-67 positive index between 50% and 80% was significantly higher than that of M-SCLC (41.2% vs 25.2%), while the proportion between 80% and 100% was lower than that of M-SCLC (51.9% vs 72.2%). There was no significant difference in the positive rates of CD56 (91.7% vs 94.6%, P=0.336), Syn (83.8% vs 84.7%, P=0.838) and CgA (54.8% vs 50.0%, P=0.632) in both tumor types. Molecular pathology results showed that frequent mutatios were TP53 (54.5%), RB1 (36.4%), KEAP1 (18.2%), MYC(18.2%), and PTEN (14.3%), and the rate of tumor mutation burden which is more than 25 mutation/Mb was 27.3%. Conclusions: LCNEC lacks specific clinical manifestations. CT imaging is powerful in distinguishing LCNEC from M-SCLC. LCNEC contains a specific mutation spectrum. Pathology combined with immunohistochemical staining is still the gold standard for LCNEC diagnosis, and the differentiation from M-SCLC mainly depends on cell size and nuclear chromatin pattern with light microscopy.

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

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

The histologic phenotype of lung cancers is associated with transcriptomic features rather than genomic characteristics.

Histology plays an essential role in therapeutic decision-making for lung cancer patients. However, the molecular determinants of lung cancer histology are largely unknown. We conduct whole-exome sequencing and microarray profiling on 19 micro-dissected tumor regions of different histologic subtypes from 9 patients with lung cancers of mixed histology. A median of 68.9% of point mutations and 83% of copy number aberrations are shared between different histologic components within the same tumors. Furthermore, different histologic components within the tumors demonstrate similar subclonal architecture. On the other hand, transcriptomic profiling reveals shared pathways between the same histologic subtypes from different patients, which is supported by the analyses of the transcriptomic data from 141 cell lines and 343 lung cancers of different histologic subtypes. These data derived from mixed histologic subtypes in the setting of identical genetic background and exposure history support that the histologic fate of lung cancer cells is associated with transcriptomic features rather than the genomic profiles in most tumors.

MMP1 drives tumor progression in large cell carcinoma of the lung through fibroblast senescence.

Large cell carcinoma (LCC) is a rare and aggressive lung cancer subtype with poor prognosis and no targeted therapies. Tumor-associated fibroblasts (TAFs) derived from LCC tumors exhibit premature senescence, and coculture of pulmonary fibroblasts with LCC cell lines selectively induces fibroblast senescence, which in turn drives LCC cell growth and invasion. Here we identify MMP1 as overexpressed specifically in LCC cell lines, and we show that expression of MMP1 by LCC cells is necessary for induction of fibroblast senescence and consequent tumor promotion in both cell culture and mouse models. We also show that MMP1, in combination with TGF-ß1, is sufficient to induce fibroblast senescence and consequent LCC promotion. Furthermore, we implicate PAR-1 and oxidative stress in MMP1/TGF-ß1-induced TAF senescence. Our results establish an entirely new role for MMP1 in cancer, and support a novel therapeutic strategy in LCC based on targeting senescent TAFs.

Activity and Immune Correlates of Programmed Death-1 Blockade Therapy in Patients With Advanced Large Cell Neuroendocrine Carcinoma.

BACKGROUND: The efficacy of anti-programmed death receptor 1 (PD-1) therapy in patients with large cell neuroendocrine carcinoma (LCNEC) remains unclear. We investigated the outcome of anti-PD-1 therapy and its predictive markers by evaluating the immune-related tumor microenvironment. PATIENTS: We retrospectively reviewed patients with advanced LCNEC treated with systemic chemotherapy. We also evaluated PD ligand 1 (PD-L1) expression (clone: 22C3), CD8-positive tumor-infiltrating lymphocytes (TILs), and the mutational profiles. RESULTS: Seventy patients were enrolled, and 13 of 70 patients received anti-PD-1 therapy. The progression-free survival (PFS) and objective response rate (ORR) of the anti-PD-1 therapy were 4.2 months and 39%, respectively. The overall survival of patients treated with anti-PD-1 therapy (n = 13) was significantly better than those treated without anti-PD-1 therapy (n = 57) (25.2 months vs 10.9 months; P = .02). Among the 13 patients treated with anti-PD-1 therapy, 10 patients (90%) had PD-L1-negative tumors. Patients with a high density of tumoral CD8-positive TILs (≥38/mm2) had a significantly better ORR and PFS than those with a low density of tumoral CD8-positive TILs (ORR: P = .02; PFS: P = .003). Additionally, all 3 patients with TP53 mutation co-occurring with PIK3CA mutation (2 of 8 patients) or RB1 mutation (1 of 8 patients) responded to anti-PD-1 therapy. CONCLUSIONS: Anti-PD-1 therapy was effective regardless of PD-L1 positivity in patients with advanced LCNEC. Our investigation might suggest that the density of tumoral CD8-positive TILs and the presence of co-occurring mutations are predictors of the efficacy of anti-PD-1 therapy in patients with advanced LCNEC.