Multiomics sequencing and immune microenvironment characteristics define three subtypes of small cell neuroendocrine carcinoma of the cervix.

Small cell cervical carcinoma (SCCC) is the most common neuroendocrine tumor in the female genital tract, with an unfavorable prognosis and lacking an evidence-based therapeutic approach. Until now, the distinct subtypes and immune characteristics of SCCC combined with genome and transcriptome have not been described. We performed genomic (n = 18), HPV integration (n = 18), and transcriptomic sequencing (n = 19) of SCCC samples. We assessed differences in immune characteristics between SCCC and conventional cervical cancer, and other small cell neuroendocrine carcinomas, through bioinformatics analysis and immunohistochemical assays. We stratified SCCC patients through non-negative matrix factorization and described the characteristics of these distinct types. We further validated it using multiplex immunofluorescence (n = 77) and investigated its clinical prognostic effect. We confirmed a high frequency of PIK3CA and TP53 alterations and HPV18 integrations in SCCC. SCCC and other small cell carcinoma had similar expression signatures and immune cell infiltration patterns. Comparing patients with SCCC to those with conventional cervical cancer, the former presented immune excluded or 'desert' infiltration. The number of CD8+ cells in the invasion margin of SCCC patients predicted favorable clinical outcomes. We identified three transcriptome subtypes: an inflamed phenotype with high-level expression of genes related to the MHC-II complex (CD74) and IFN-α/ß (SCCC-I), and two neuroendocrine subtypes with high-level expression of ASCL1 or NEUROD1, respectively. Combined with multiple technologies, we found that the neuroendocrine groups had more TP53 mutations and SCCC-I had more PIK3CA mutations. Multiplex immunofluorescence validated these subtypes and SCCC-I was an independent prognostic factor of overall survival. These results provide insights into SCCC tumor heterogeneity and potential therapies. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Retinopatía autoinmune asociada a la presencia de anticuerpos onconeuronales: a propósito de un caso / Autoimmune retinopathy with onconeuronal antibodies: Case report

Se presenta el caso de retinopatía autoinmune en un paciente con carcinoma microcítico de pulmón, no conocido hasta el momento, que se diagnosticó tras la exploración oftalmológica. La serología fue positiva para anticuerpos onconeuronales CV2/CRMP5. La retinopatía autoinmune es una entidad rara que puede pasarse por alto, y ser infradiagnosticada. Se produce por una reacción inmunomediada contra antígenos retinianos. La importancia de su diagnóstico precoz radica en que en muchos de los pacientes la sintomatología ocular aparece antes del diagnóstico del cáncer primario, por lo que su identificación y derivación precoz para estudio de extensión puede suponer el diagnóstico de una neoplasia primaria oculta hasta el momento. (AU)

We present a case of autoimmune retinopathy in a patient with unknown small cell lung cáncer (SCLC), which was diagnosed after ophthalmological examination. Serology was positive for CV2/CRMP5 onconeuronal antibodies. Autoimmune retinopathy is a rare entity that can be missed and underdiagnosed. It is produced by an immune-mediated reaction against retinal antigens. The importance of its early diagnosis lies in the fact that in many of the patients, ocular symptoms appear before the diagnosis of the primary cancer, so its early identification and referral for an extension study may lead to the diagnosis of a hidden primary neoplasm. (AU)

ISOTOPE: ISOform-guided prediction of epiTOPEs in cancer.

Immunotherapies provide effective treatments for previously untreatable tumors and identifying tumor-specific epitopes can help elucidate the molecular determinants of therapy response. Here, we describe a pipeline, ISOTOPE (ISOform-guided prediction of epiTOPEs In Cancer), for the comprehensive identification of tumor-specific splicing-derived epitopes. Using RNA sequencing and mass spectrometry for MHC-I associated proteins, ISOTOPE identified neoepitopes from tumor-specific splicing events that are potentially presented by MHC-I complexes. Analysis of multiple samples indicates that splicing alterations may affect the production of self-epitopes and generate more candidate neoepitopes than somatic mutations. Although there was no difference in the number of splicing-derived neoepitopes between responders and non-responders to immune therapy, higher MHC-I binding affinity was associated with a positive response. Our analyses highlight the diversity of the immunogenic impacts of tumor-specific splicing alterations and the importance of studying splicing alterations to fully characterize tumors in the context of immunotherapies. ISOTOPE is available at https://github.com/comprna/ISOTOPE.

TruNeo: an integrated pipeline improves personalized true tumor neoantigen identification.

BACKGROUND: Neoantigen-based personal vaccines and adoptive T cell immunotherapy have shown high efficacy as a cancer treatment in clinical trials. Algorithms for the accurate prediction of neoantigens have played a pivotal role in such studies. Some existing bioinformatics methods, such as MHCflurry and NetMHCpan, identify neoantigens mainly through the prediction of peptide-MHC binding affinity. However, the predictive accuracy of immunogenicity of these methods has been shown to be low. Thus, a ranking algorithm to select highly immunogenic neoantigens of patients is needed urgently in research and clinical practice. RESULTS: We develop TruNeo, an integrated computational pipeline to identify and select highly immunogenic neoantigens based on multiple biological processes. The performance of TruNeo and other algorithms were compared based on data from published literature as well as raw data from a lung cancer patient. Recall rate of immunogenic ones among the top 10-ranked neoantigens were compared based on the published combined data set. Recall rate of TruNeo was 52.63%, which was 2.5 times higher than that predicted by MHCflurry (21.05%), and 2 times higher than NetMHCpan 4 (26.32%). Furthermore, the positive rate of top 10-ranked neoantigens for the lung cancer patient were compared, showing a 50% positive rate identified by TruNeo, which was 2.5 times higher than that predicted by MHCflurry (20%). CONCLUSIONS: TruNeo, which considers multiple biological processes rather than peptide-MHC binding affinity prediction only, provides prioritization of candidate neoantigens with high immunogenicity for neoantigen-targeting personalized immunotherapies.

Worsening of anti-Hu paraneoplastic neurological syndrome related to anti-PD-1 treatment: Case report and review of literature.

We present an illustrative case of a 62-year-old woman with small cell lung cancer who developed progressive worsening of pre-existing anti-Hu antibody associated sensory neuronopathy after treatment with programmed cell death-1 (PD-1) inhibitor, nivolumab. We review the literature and identify 6 reported cases to understand the clinical outcomes of patients with anti-Hu paraneoplastic neurologic syndrome (PNS) treated with anti-PD-1 treatment. The PNS clinical spectrum comprised of encephalitis, a combination of sensory neuronopathy and anti-NMDAR encephalitis, isolated sensory neuronopathy, and encephalomyelitis. Immune checkpoint inhibitor have the potential to worsen pre-existing anti-Hu PNS and may promote the development of anti-Hu PNS.

Tumor-Infiltrating Immune Cells and PD-L1 as Prognostic Biomarkers in Primary Esophageal Small Cell Carcinoma.

Primary esophageal small cell carcinoma (PESCC) is a weakly prevalent but lethal malignancy with early metastasis and a poor prognosis. Currently, neither effective prognostic indicators nor curative therapies are available for PESCC. Immunotherapy has now evolved into one of the most promising therapies for cancer patients. Tumor-infiltrating immune cells which are integral to the tumor immune microenvironment (TIME) are recognized as highly important for prognosis prediction, while the responsiveness to immune checkpoint blockade may be subject to the features of TIME. In this study, we aim to identify the TIME and provide indication for the applicability of immune checkpoint therapy in PESCC. We found that PD-L1 expression was detected in 33.33% (27/81) of all the patients, mostly exhibiting a stroma-only pattern and that it was positively associated with tumor-infiltrating immune cells (CD4+, CD8+, and CD163+). In 74.07% of PD-L1-positive specimens, PD-L1+CD163+ cells were colocalized more with CD4+ than CD8+ T cells. 83.95% (68/81) of all the specimens were infiltrated with more CD4+ than CD8+ T cells. Further analysis showed FoxP3+ Tregs constituted 13-27% of the total CD4+ T cell population. The Kaplan--Meier analysis indicated several factors that contribute to poor survival, including negative PD-L1 expression, rich CD4 expression, rich FoxP3 expression, a low CD8/CD4 ratio, and a high FoxP3/CD8 ratio. A nomogram model was constructed and showed good performance for survival prediction. These results highlight that a suppressive TIME contributes to poor survival of patients with PESCC. TIME analyses might be a promising approach to evaluate the possibility and effect of immune checkpoint-based immunotherapeutics in PESCC patients.

Dendritic Cell-Based Immunotherapy in Lung Cancer.

Lung cancer remains the leading cause of cancer-related death worldwide. The advent of immune checkpoint inhibitors has led to a paradigm shift in the treatment of metastatic non-small cell and small cell lung cancer. However, despite prolonged overall survival, only a minority of the patients derive clinical benefit from these treatments suggesting that the full anti-tumoral potential of the immune system is not being harnessed yet. One way to overcome this problem is to combine immune checkpoint blockade with different strategies aimed at inducing or restoring cellular immunity in a tumor-specific, robust, and durable way. Owing to their unique capacity to initiate and regulate T cell responses, dendritic cells have been extensively explored as tools for immunotherapy in many tumors, including lung cancer. In this review, we provide an update on the nearly twenty years of experience with dendritic cell-based immunotherapy in lung cancer. We summarize the main results from the early phase trials and give an overview of the future perspectives within this field.

Immune Exclusion Is Frequent in Small-Cell Carcinoma of the Bladder.

Small-cell cancer of the urinary bladder is a rare but highly aggressive disease. It is currently unclear whether immune checkpoint therapies that have been approved for urothelial carcinomas will also be efficient in small-cell carcinomas. In this study, we analyzed potential predictors of response including PD-L1 expression and the quantity and location of tumor-infiltrating lymphocytes (TILs) in 12 small-cell and 69 "classical" urothelial cancers by immunohistochemistry. The analysis revealed that small-cell carcinomas were characterized by the virtual absence of PD-L1 expression and an "immune-excluded" phenotype with only a few TILs in the center of the tumor (CT). In small-cell carcinomas, the average immune cell density in the CT (CD3: 159 ± 206, CD8: 87 ± 169 cells/mm2) was more than 3 times lower than that in the urothelial carcinomas (CD3: 625 ± 800, p < 0.001; CD8: 362 ± 626 cells/mm2, p = 0.004) while there was no significant difference in the immune cell density at the invasive margin (IM) (small-cell carcinomas CD3: 899 ± 733, CD8: 404 ± 433 cells/mm2; urothelial carcinomas CD3: 1167 ± 1206, p = 0.31; CD8: 582 ± 864 cells/mm2, p = 0.27). Positive PD-L1 staining was found in 39% of urothelial cancers, but in only 8% of small-cell bladder cancer cases (p = 0.04). Concordant with these data, a sharp decrease of PD-L1 positivity from >80% to 0% positive cells and of TILS in the CT from 466-1063 CD3-positive cells/mm2 to 50-109 CD3-positive cells/mm2 was observed in two cancers with clear-cut progression from "classical" urothelial to small-cell carcinoma. In conclusion, these data demonstrate that small-cell bladder cancer commonly exhibits an immune-excluded phenotype.

Combined Treatment with Autologous CIK Cells, Radiotherapy and Chemotherapy in Advanced Cervical Cancer.

To investigate the clinical efficacy of autologous cytokine induced killer (CIK) cells transfusion combined with radiochemotherapy in the treatment of advanced cervical cancer. A total of 89 hospitalized patients with advanced cervical cancer were admitted and divided into the treatment group (44 cases, autologous CIK cells transfusion combined with radiochemotherapy) and the control group (45 cases, radiochemotherapy) by a randomized non-blind method. Comparisons of therapeutic efficacies, immune functions, life qualities and survival rates were analyzed between the two groups. The short-term therapeutic efficacy of the treatment group was significantly higher than that of the control group. There was no significant difference in 1, 2 and 3 year survival rates between the two groups. Compared with pre-treatment, levels of CD3+, CD4+/CD8+ in peripheral blood were increased in the CIK group, which were reduced in the control group. In the CIK group,only the feeling was depressed on the 25th day post-treatment (T25) compared with the day before treatment (B1). However in the control group, the function of body, role, social and holistic health was obvious disordered on day T25 compared with day B1. On day T25, there were significant differences in function of body, social and holistic health between two groups. Autologous CIK cells transfusion combined with radiochemotherapy shows better short-term efficacy than radiochemotherapy alone in the treatment of advanced cervical cancer, which obviously improves immune function and life quality of patients with low side effects.

PD-L1 expression in tumor cells and the immunologic milieu of bladder carcinomas: a pathologic review of 165 cases.

Programmed death ligand 1 (PD-L1) is a transmembrane protein that plays a major role in immune suppression. Its interaction with the receptor PD-1 results in downregulation of antitumoral immunity. Humanized monoclonal antibodies that interrupt the PD-L1/PD-1 interaction have shown therapeutic efficacy in patients with advanced urothelial cancer. However, immunohistochemical staining of PD-L1 in bladder tumors and its relationship to tumor histologic type, grade, and overall survival has been incompletely analyzed. Slides from 165 cystectomy specimens were reviewed for tumor type, grade of urothelial carcinoma, pathologic stage, and overall survival. A tissue microarray (TMA) using four 0.6 mm cores from each case was constructed. Immunohistochemistry was performed on the TMA using a variety of new PD-L1 antibodies and platforms now widely available. For each case, the percent of tumor cells positive for PD-L1 and the percent of positive immune cells were scored. The overall number of bladder cancers positive for PD-L1 depended on the antibody/platform combination used and the threshold for considering a tumor "PD-L1-positive." Squamous cell carcinomas (SCCs) of the bladder demonstrated PD-L1 positivity more frequently than urothelial cell carcinomas (UCCs). High-grade UCCs were positive for PD-L1 on tumor cells more frequently than low-grade UCCs. There was no difference in survival between PD-L1-positive and PD-L1-negative bladder cancers in our study. Further studies should consider examining the predictive significance of PD-L1 IHC in bladder cancers.

Immunohistochemical expression and prognostic value of PD-L1 in Extrapulmonary small cell carcinoma: a single institution experience.

BACKGROUND: Extrapulmonary small cell carcinomas (ESCC) are rare but aggressive tumors. Relapses are common despite treatment with chemotherapy and/or radiotherapy. Prospective data for treatment of ESCC are lacking; treatment of these cancers usually incorporates lung small cell carcinoma treatment recommendations. Cancer staging remains the most important prognostic factor. Cancer immunotherapy targeting the PD-1/PD-L1 pathway has shown efficacy in multiple tumor types, and could be an appealing treatment strategy for these rare tumors. METHODS: We investigated PD-L1 expression by immunochemistry (IHC) in ESCCs diagnosed at University of Massachusetts Medical Center, from 1999 to 2016. 34 cases with sufficient material were selected for PD-L1 IHC analysis using clone E1L3N. PD-L1 expression was evaluated using the combined positive score (CPS). Retrospective chart review was performed. We evaluated the incidence and prognostic value of PD-L1 expression in ESCC at our institution. RESULTS: Twelve out 34 cases (35%) had PD-L1 CPS scores ≥1. Ten cases had CPS scores ranging 1-5, whereas 2 cases had CPS scores > 80. The overall response rate to the standard chemotherapy with/without radiotherapy in the PD-L1 positive group was 80% versus 67% for the PDL-1 negative group (p-value 0.67). The median overall survival for the PD-L1 positive group, regardless of stage, was 11.5 months versus 7 months for PD-L1 negative group (p-value 0.34). Patients with limited stage disease with positive PD-L1 had a median survival of 53 months compared to 15 months for patients with PD-L1 negative limited stage (p-value 0.80). CONCLUSIONS: This study showed that at least one third of our ESCC tissue samples expressed PD-L1. There was a trend for higher response rates to the standard chemotherapy with/without radiotherapy and improved survival in PD-L1 positive patients. Further studies are required to understand the implications of immune dysregulation in these aggressive tumors. PD-L1/PD-1 inhibitors should be investigated in this group of patients.

Anti-Podocalyxin Monoclonal Antibody 47-mG2a Detects Lung Cancers by Immunohistochemistry.

Lung cancer is one of the leading causes of cancer-related deaths in the world. Regardless of the advances in lung cancer treatments, the prognosis is still poor. Podocalyxin (PODXL) is a highly glycosylated type I transmembrane protein that is expressed in normal tissues, including the heart, pancreas, and breast. It is also found and used as a diagnostic marker in many cancers, such as renal, brain, breast, oral, and lung cancers. We previously developed specific and sensitive anti-PODXL monoclonal antibodies, PcMab-47 (mouse IgG1, kappa) and its mouse IgG2a-type (47-mG2a), both of which were suitable for immunohistochemical analyses of oral cancers. In this study, we investigated the utility of PcMab-47 and 47-mG2a for the immunohistochemical analyses of lung cancers. PcMab-47 stained 51/70 (72.9%) cases of lung cancer, whereas 47-mG2a stained 59/70 (84.3%) cases, indicating that the latter antibody is more sensitive and is useful for detecting PODXL in lung cancers.

Immune-Active Microenvironment in Small Cell Carcinoma of the Ovary, Hypercalcemic Type: Rationale for Immune Checkpoint Blockade.

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), is a highly aggressive monogenic cancer driven by SMARCA4 mutations. Here, we report responses to anti-PD1 immunotherapy in four patients and characterize the immune landscape of SCCOHT tumors using quantitative immunofluorescence and gene expression profiling. Unexpectedly for a low mutation burden cancer, the majority of the tumors (eight of 11 cases) demonstrated PD-L1 expression with strong associated T-cell infiltration (R2 = 0.60-0.95). PD-L1 expression was detected in both tumor and stromal cells, with macrophages being the most abundant PD-L1-positive cells in some tumors (three of 11 cases). Transcriptional profiling revealed increased expression of genes related to Th1 and cytotoxic cell function in PD-L1-high tumors, suggesting that PD-L1 acts as a pathway of adaptive immune resistance in SCCOHT. These findings suggest that although SCCOHT are low-mutational burden tumors, their immunogenic microenvironment resembles the landscape of tumors that respond well to treatment with PD-1/PD-L1 blockade.

New Immunotherapy and Lung Cancer. / Nueva inmunoterapia y cáncer de pulmón.

Recent research on the relationship between the immune system and cancer has revealed the molecular mechanisms by which cancer cells co-opt certain T cell receptors which block the cytotoxic response to defend themselves from the antitumor immune attack. These findings have helped identify specific targets (T cell receptors or their corresponding ligands) for the design of monoclonal antibodies that can unlock the immune response. These drugs, known as immune checkpoint inhibitors, have shown efficacy in metastatic melanoma and kidney cancer, and have been successfully tested in non-small cell lung cancer in recent trials. Immune checkpoint inhibitors were included in clinical practice as a second-line option after an initial chemotherapy (CT) regimen, and in the last year positive results have been reported from randomized trials in which they were compared in first line with standard CT. Responses have been surprising and durable, but less than 20%-25% in unselected patients, so it is essential that factors predicting efficacy be identified. One such biomarker is PD-L1, but the different methods used to detect it have produced mixed results. This non-systematic review discusses the results of the latest trials, the possibilities of incorporating these drugs in first-line regimens, the criteria for patient selection, adverse effects, and the prospects of combinations with conventional treatment modalities, such as CT, radiation therapy, and antiangiogenic agents.

The next generation of immunotherapy: keeping lung cancer in check.

Lung cancer is the deadliest malignancy with more cancer deaths per year than the next three cancers combined. Despite remarkable advances in targeted therapy, advanced lung cancer patients have not experienced a significant improvement in mortality. Lung cancer has been shown to be immunogenic and responsive to checkpoint blockade therapy. Checkpoint signals such as CTLA-4 and PD-1/PD-L1 dampen T cell activation and allow tumors to escape the adaptive immune response. Response rates in patients with pretreated, advanced NSCLC were much higher and more durable with PD-1 blockade therapy compared to standard-of-care, cytotoxic chemotherapy. Therefore, PD-1 inhibitors such as nivolumab and pembrolizumab were rapidly approved for both squamous and nonsquamous lung cancer in the pretreated population. The advent of these new therapies have revolutionized the treatment of lung cancer; however, the majority of NSCLC patients still do not respond to PD-1/PD-L1 inhibition leaving an unmet need for a large and growing population.Immunotherapy combinations with chemotherapy, radiation therapy, or novel immunomodulatory agents are currently being examined with the hope of achieving higher response rates and improving overall survival rate. Chemotherapy and radiation therapy has been theorized to increase the release of tumor antigen leading to increased responses with immunotherapy. However, cytotoxic chemotherapy and radiation therapy may also destroy actively proliferating T cells. The correct combination and order of therapy is under investigation. The majority of patients who do respond to immunotherapy have a durable response attributed to the effect of adaptive immune system's memory. Unfortunately, some patients' tumors do progress afterward and investigation of checkpoint blockade resistance is still nascent.This review will summarize the latest efficacy and safety data for early and advanced NSCLC in both the treatment-naïve and pretreated settings. The emerging role of immunotherapy for the treatment of small cell lung cancer and malignant mesothelioma will also be discussed.

Soluble Human Leukocyte Antigen-G in the Bronchoalveolar Lavage of Lung Cancer Patients. / Antígeno leucocitario humano-G soluble en el lavado broncoalveolar de pacientes con cáncer pulmonar.

BACKGROUND: The main function of the HLA-G molecule in its membrane-bound and soluble forms is to inhibit the immune response by acting on CD4+ T cells, cytotoxic T cells, NK cells and dendritic cells. Lung cancer is a leading cause of death worldwide, and annual incidence is high in both women and men. Some studies have reported an increase of HLA-G serum levels in lung cancer, probably generated by tumor cells escaping the antitumor immune response. In this study the concentration of soluble HLA-G in bronchoalveolar lavage (BAL) in patients with primary and metastatic lung cancer was measured to determine its relation with tumor histological type and overall patient status according to the Karnofsky scale. METHODS: Thirty-one lung cancer patients were included. A tumor biopsy was obtained by bronchoscopy and the tumor type was determined by hematoxylin and eosin staining. BAL samples were obtained to measure soluble HLA-G concentrations in an ELISA sandwich assay. RESULTS: The average value of soluble HLA-G was 49.04ng/mL. No correlation between soluble HLA-G levels and age, gender or smoking was observed. A highly significant difference was observed in the levels of soluble HLA-G in BAL from patients with different histological types of lung cancer, especially in metastatic tumors. The Karnofsky index showed a significant and inverse correlation with soluble HLA-G levels in BAL. CONCLUSIONS: Soluble HLA-G protein is significantly associated with metastatic tumors and patients with lower Karnofsky index and may be useful as a prognostic marker in lung cancer.

Clinical and Histological Features of Small Cell Lung Cancer Paraneoplastic Inflammatory Uveitis.

PURPOSE: Paraneoplastic ocular inflammation can be associated with the autoantibody against collapsin response-mediator protein-5 (anti-CRMP-5). We describe the clinical and histological features of 2 rare cases of small cell lung carcinoma (SCLC) presenting with intraocular inflammation: the first was anti-CRMP-5 positive and the second preceded the auto-antibody's discovery but with remarkably similar features. The previously unreported retinal histology is described. METHODS: Case notes review. RESULTS: Both cases presented with bilateral visual loss, constricted visual fields, vitritis, and pale, swollen optic discs. Fundal fluorescein angiographies showed optic disc leakage. Retinal histology of both cases revealed predominantly inner retinal inflammation. Following their diagnosis with SCLC, serology for case 1 was positive for anti-CRMP-5 but case 2 pre-dated its discovery. CONCLUSIONS: CRMP-5 inflammatory eye disease presents with a distinct pattern of clinical and histological features, which may be the first sign of their underlying cancer. Retinal histology revealed predominantly inner retinal inflammation.

Smoking, inflammation and small cell lung cancer: recent developments.

Small cell lung cancer (SCLC) accounts for 15 % of all lung tumors and represents an invasive neuroendocrine malignancy with poor survival rates. This cancer is highly prevalent in smokers and characterized by inactivation of p53 and retinoblastoma. First in vitro expansion of circulating tumor cells (CTCs) of SCLC patients allowed for investigation of the cell biology of tumor dissemination. In the suggested CTC SCLC model, the primary tumor attracts and educates tumor-promoting and immunosuppressive macrophages which in turn arm CTCs to spread and generate distal lesions. Preexisting inflammatory processes associated with chronic obstructive pulmonary disease (COPD) seem to potentiate the subsequent activity of tumor-associated macrophages (TAM). Activation of signal transducer and activator of transcription 3 (STAT3) and expression of chitinase-3-like 1/YKL-40 in SCLC CTCs seems to be associated with drug resistance. In conclusion, inflammation-associated generation of invasive and chemoresistant CTCs most likely explains the characteristic features of SCLC, namely early dissemination and rapid failure of chemotherapy.

Lambert-Eaton syndrome antibodies target multiple subunits of voltage-gated Ca2+ channels.

INTRODUCTION: Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune presynaptic neuromuscular disorder. Autoantibodies against subunits of voltage-gated calcium channels (VGCCs) associated with acetylcholine release are thought to cause LEMS. METHODS: HEK293 cells expressing specific individual recombinant subunits of α(1A), α(1B), α(1C), and α(1E); ß(3); and α(2)δ of human neuronal VGCCs were exposed to antibodies from 3 LEMS patients, 1 patient with small-cell lung carcinoma, and 1 with myasthenia gravis. RESULTS: All LEMS patient antibodies bound to cells containing any of the α(1) or ß(3) subunits alone or combined with α(2)δ subunits, but not α(2)δ alone. Autoantibodies from the patient with small-cell lung carcinoma but not the myasthenia gravis patient targeted the same VGCC subunits. CONCLUSIONS: Autoantibodies from LEMS patients bind directly to multiple VGCC α(1) subunits as well as the ß(3) subunit. Thus, multiple components of the presynaptic VGCC complex are prospective targets for antibodies in LEMS.