DNA methylation regulates together with other epigenetic mechanisms the transcriptional activity of genes and is involved in the pathogenesis of malignant diseases including lung cancer. In non-small cell lung cancer (NSCLC) various tumor suppressor genes are already known to be tumor-specifically methylated. However, from the vast majority of a large number of genes which were identified to be tumor-specifically methylated, tumor-specific methylation was unknown so far. Thus, the major aim of this study was to investigate in detail the mechanism(s) responsible for transcriptional regulation of the genes SPAG6 and L1TD1 in NSCLCs. We analysed publically available RNA-sequencing data and performed gene expression analyses by RT-PCR. DNA methylation analyses were done by methylation-sensitive high-resolution melt analyses and bisulfite genomic sequencing. We additionally investigated protein expression using immunohistochemistry. Cell culture experiments included tumor cell growth, proliferation, viability as well as colony formation assays. Moreover, we performed xenograft experiments using immunodeficient mice. We observed frequent downregulation of SPAG6 and L1TD1 mRNA expression in primary tumor (TU) samples compared to corresponding non-malignant lung tissue (NL) samples of NSCLC patients. We furthermore observed re-expression of both genes after treatment with epigenetically active drugs in most NSCLC cell lines with downregulated SPAG6 and L1TD1 mRNA expression. Frequent tumor-specific DNA methylation of SPAG6 and L1TD1 was detected when we analysed TU and corresponding NL samples of NSCLC patients. ROC curve analyses demonstrated that methylation of both genes is able to distinguish between TU and NL samples of these patients. Immunohistochemistry revealed a close association between SPAG6/L1TD1 methylation and downregulated protein expression of these genes. Moreover, by performing functional assays we observed reduced cell growth, proliferation and viability of pCMV6-L1TD1 transfected NSCLC cells. In addition, reduced volumes of tumors derived from pCMV6-L1TD1 compared to pCMV6-ENTRY transfected NCI-H1975 cells were seen in a xenograft tumor model. Overall, our results demonstrate that SPAG6 and L1TD1 are tumor-specifically methylated in NSCLCs and that DNA methylation is involved in the transcriptional regulation of these genes. Moreover, in vitro as well as in vivo experiments revealed tumor-cell growth suppressing properties of L1TD1 in NSCLC cells.

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.

Objective: To report the clinical features of 20 newly diagnosed patients with GABA_B receptor (GABA_BR) antibodies and determine the frequency of associated tumors and concurrent neuronal autoantibodies. Methods: Clinical data were retrospectively obtained and evaluated. Serum and CSF samples were examined for additional antibodies using methods previously reported. Results: Seventeen patients presented with seizures, memory loss, and confusion, compatible with limbic encephalitis (LE), one patient presented with ataxia, one patient presented with status epilepticus, and one patient presented with opsoclonus-myoclonus syndrome (OMS). Nineteen (95%) patients eventually developed LE during the course of the disease. Small-cell lung cancer (SCLC) was identified in 10 (50%) patients, all with LE. Treatment and outcome was available from 19 patients: 15 showed complete (n = 7) or partial (n = 8) neurologic improvement after steroids, IV immunoglobulins, or plasma exchange and oncologic treatment when indicated; 1 patient died of tumor progression shortly after the first cycle of immunotherapy, and 3 were not treated. Five patients with SCLC had additional onconeuronal antibodies (Ri, amphiphysin, or SOX1), and 2 without tumor had GAD65 and NMDAR antibodies, respectively. GABA_BR antibodies were not detected in serum of 116 patients with SCLC without neurologic symptoms. Conclusion: Our study confirms GABA_BR as an autoantigen of paraneoplastic and nonparaneoplastic LE and expands the phenotype of GABA_BR antibodies to ataxia, OMS, and status epilepticus. The long-term prognosis is dictated by the presence of a tumor. Recognition of syndromes associated with GABA_BR antibodies is important because they usually respond to treatment.

Anti‐angiogenic therapies have shown limited efficacy in the clinical management of metastatic disease, including lung metastases. Moreover, the mechanisms via which tumours resist anti‐angiogenic therapies are poorly understood. Importantly, rather than utilizing angiogenesis, some metastases may instead incorporate pre‐existing vessels from surrounding tissue (vessel co‐option). As anti‐angiogenic therapies were designed to target only new blood vessel growth, vessel co‐option has been proposed as a mechanism that could drive resistance to anti‐angiogenic therapy. However, vessel co‐option has not been extensively studied in lung metastases, and its potential to mediate resistance to anti‐angiogenic therapy in lung metastases is not established. Here, we examined the mechanism of tumour vascularization in 164 human lung metastasis specimens (composed of breast, colorectal and renal cancer lung metastasis cases). We identified four distinct histopathological growth patterns (HGPs) of lung metastasis (alveolar, interstitial, perivascular cuffing, and pushing), each of which vascularized via a different mechanism. In the alveolar HGP, cancer cells invaded the alveolar air spaces, facilitating the co‐option of alveolar capillaries. In the interstitial HGP, cancer cells invaded the alveolar walls to co‐opt alveolar capillaries. In the perivascular cuffing HGP, cancer cells grew by co‐opting larger vessels of the lung. Only in the pushing HGP did the tumours vascularize by angiogenesis. Importantly, vessel co‐option occurred with high frequency, being present in >80% of the cases examined. Moreover, we provide evidence that vessel co‐option mediates resistance to the anti‐angiogenic drug sunitinib in preclinical lung metastasis models. Assuming that our interpretation of the data is correct, we conclude that vessel co‐option in lung metastases occurs through at least three distinct mechanisms, that vessel co‐option occurs frequently in lung metastases, and that vessel co‐option could mediate resistance to anti‐angiogenic therapy in lung metastases. Novel therapies designed to target both angiogenesis and vessel co‐option are therefore warranted. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Purpose: Recent experimental studies have revealed that lymphangiogenesis plays an important role in cancer progression, but its clinical significance in the case of non-small cell lung cancer (NSCLC) remains unclear. Our aim was to assess the lymphangiogenesis of human NSCLC, and to correlate this with angiogenic phenotype (angiogenic versus nonangiogenic growth pattern) and clinical behavior. Experimental Design: One hundred and three patients with NSCLC and complete follow-up information were included. Tumor samples were immunostained for vascular endothelial growth factor-C (VEGF-C), the lymphatic endothelial markers, LYVE-1 and D2-40/Podoplanin, and the panvascular marker, CD31. Lymphatic vessel density (LVD) and perimeters were evaluated within the tumor and peritumorally. Results: LVDs at the tumor periphery were significantly higher in lymph node metastatic tumors (P < 0.005) and high LVDs correlated with poor overall survival (P < 0.001). However, this tendency proved to be significant only in the angiogenic tumor group (P < 0.001). Although 68% of the patients with nonangiogenic tumors had lymph node metastasis (P = 0.0048 versus angiogenic tumors), in the patient group with nonangiogenic NSCLCs, there was no information from the LVDs in any investigated tumor area (P > 0.05). In contrast to angiogenic tumors, which had actively sprouting lymphatics in all of the investigated tumor areas, nonangiogenic tumors showed no Ki67 staining intratumorally. Conclusions: Our results reveal tumor lymphangiogenesis as a novel prognostic indicator for the risk of lymph node metastasis in NSCLC. Moreover, it also provides the first evidence that nonangiogenic NSCLCs mainly co-opt host tissue lymphatics during their growth, in contrast to most of the angiogenic tumors, which expand with concomitant lymphangiogenesis.