Primary Resistance to RET Inhibition in a RET Fusion-Positive Pancreatic Neuroendocrine Carcinoma.

We present a 54-year-old White male with a diagnosis of stage IV pancreatic neuroendocrine carcinoma. Next-generation sequencing of the tumor/blood identified a complex tumor genome, which included a rearranged during transfection (RET) gene fusion. The patient initially received cytotoxic chemotherapy with a significant radiographic response. After 4 cycles of chemotherapy, the patient was transitioned to a clinical trial using selpercatinib, a RET inhibitor, as maintenance therapy. Unfortunately, our patient developed progression of disease at the first treatment monitoring scan. Our patient suffered primary resistance to RET-targeted therapy. Proposed mechanisms of resistance include intrinsic resistance of the nuclear receptor co-activator 4-RET fusion to RET inhibition, the RET fusion representing a passenger alteration to another tumorigenic driver pathway and/or decreased efficacy of RET inhibition after platinum-based chemotherapy. Our patient's clinical course highlights the fact that "actionable" genomic alterations do not always equate to patient benefit.

Paget Disease of Bone Harboring Bone Metastatic Neuroendocrine Cancer: A Case Report.

In this case report, we describe an uncommon case of neuroendocrine cancer of unknown origin began with cauda equina syndrome in a patient affected by Paget disease of bone (PDB). A 76-year-old man with diagnosis of PDB, without history of pain or bone deformity, developed sudden severe low back pain. Bone alkaline phosphatase was increased and MRI and whole-body scintigraphy confirmed the localization of the disease at the third vertebra of the lumbar spine. Treatment with Neridronic Acid was started, but after only 2 weeks of therapy anuria and bowel occlusion occurred together with lower limb weakness and walking impairment. Cauda equina syndrome consequent to spinal stenosis at the level of L2-L3 was diagnosed after admission to Emergency Department and the patient underwent neurosurgery for spinal medulla decompression. The histologic results showed a complete subversion of bone structure in neoplastic tissue, consistent with metastatic neuroendocrine carcinoma of unknown origin. In conclusion, low back pain in the elderly may require deep investigation to individuate rare diseases. In asymptomatic patients with apparently stable PDB, the sudden appearance of pain or neurologic symptoms may alert the clinician for the possibility of other superimposing diseases, like bone metastases.

Treatment Outcomes of Second-Line Systemic Therapy for Neuroendocrine Prostate Cancer: A Report of Four Cases.

Neuroendocrine prostate cancer (NEPC) is a histological variant of prostate cancer and is characterized by aggressiveness and poor clinical outcomes. NEPC usually develops as a mechanism of treatment resistance in patients receiving hormone therapy for advanced prostate cancer. NEPC is sensitive to primary platinum-based chemotherapy, and has a short response duration. Second-line therapy is required in many cases, but clinical data on subsequent treatment after progression to first-line chemotherapy is limited. Here we report our experience of four cases of NEPC treated with second-line chemotherapy. Progression-free and overall survival rates were very low in three of the patients. One patient received multidisciplinary therapy using systemic and local chemotherapy and radiation therapy and survived for 24 months after initiation of second-line chemotherapy. Multidisciplinary therapy with chemotherapy and radiation is a promising option for improving the survival of patients with NEPC.

The genetic alterations of rectal neuroendocrine tumor and indications for therapy and prognosis: a systematic review.

Neuroendocrine tumors (NETs) are a type of rare tumor that can occur at multiple organs. Rectal NETs are the most common NETs in gastrointestinal tract. Due to the rarity of rectal NETs in rectal cancer, the molecular features and the correlation with patient therapeutic response and prognosis have not been investigated in detail. In this review, we focused on the molecular features, potential therapeutic targets and prognosis of rectal NETs. By summarizing the relevant studies, we established the mutational landscape of rectal NETs and identified a series of large fragment variations. Driver genes including TP53, APC, KRAS, BRAF, RB1, CDKN2A and PTEN were found as the top mutated genes. Large fragment alterations mainly involved known driver genes, including APC, TP53, CCNE1, MYC, TERT, RB1 and ATM. Germline mutations of APC, MUTYH, MSH6, MLH1 and MSH2 associated with Lynch syndrome or FAP were also found in rectal NETs. The BRAF-V600E mutation was reported as an actionable target in rectal NETs, and the combined BRAF/MEK inhibitors were found to be effective targeting BRAF-V600E in advanced or metastatic NETs. The known prognostic risk factors of rectal adenocarcinoma, including a series of demographic and clinicopathological factors were also prognostic factors for rectal NETs. Furthermore, three types of markers, including genetic alterations, protein expression levels and methylation, were also suggested as prognostic factors for rectal NETs. In summary, we established the landscape of mutations and large-fragment alterations of rectal NETs, and identified potential therapeutic targets and a series of prognostic factors. Future studies may focus on the optimization of therapeutic strategies based on potential actionable biomarkers.

Contemporary outcomes of esophageal and gastroesophageal junction neuroendocrine tumors.

Adenocarcinoma and squamous cell esophageal cancers have been extensively studied in the literature. Esophageal neuroendocrine (NET)/carcinoid tumors are less commonly studied and have only been described in small series. The purpose of this study was to describe the demographics and natural history of esophageal NETs, as well as optimal treatments. We hypothesized that surgical resection would be the best treatment of esophageal NETs. The National Cancer Database was used to identify adult patients with esophageal or gastroesophageal junction (GEJ) cancer from 2004 to 2018. Patients were characterized as carcinoid/NET, adenocarcinoma, or squamous cell cancer. Clinical and demographic characteristics were compared between the histology groups. The primary outcome was overall survival, which was assessed by multivariable Cox analysis. Multivariable Cox analysis was also used to analyze factors associated with survival among NET patients who underwent surgery. Among 206,321 patients with esophageal cancer, 1,563 were NETs (<0.01%). Relative to the other two histologies, NETs were associated with younger age, female sex, and advanced clinical stage at diagnosis. Multivariate analysis suggested that NETs were less likely to be treated with surgical resection (OR 0.51, P < 0.001). Nonetheless, surgical resection was associated with improved survival (HR 0.64, P = 0.003). Among patients with NETs who received surgery, neoadjuvant therapy was associated with improved overall survival (HR 0.38, P = 0.013). NET of the esophagus presents with more advanced disease than other common histologies. Among patients with nonmetastatic cancer, surgical resection appears to be the best treatment. Neoadjuvant systemic therapy may offer survival benefit, but future studies are necessary.

Neuroendocrine Differentiation of Lung Cancer Cells Impairs the Activation of Antitumor Cytotoxic Responses in Mice.

Lung cancer has the highest mortality among all types of cancer; during its development, cells can acquire neural and endocrine properties that affect tumor progression by releasing several factors, some acting as immunomodulators. Neuroendocrine phenotype correlates with invasiveness, metastasis, and low survival rates. This work evaluated the effect of neuroendocrine differentiation of adenocarcinoma on the mouse immune system. A549 cells were treated with FSK (forskolin) and IBMX (3-Isobutyl-1-methylxanthine) for 96 h to induce neuroendocrine differentiation (NED). Systemic effects were assessed by determining changes in circulating cytokines and immune cells of BALB/c mice immunized with PBS, undifferentiated A549 cells, or neuroendocrine A549NED cells. A549 cells increased circulating monocytes, while CD4+CD8- and CD4+CD8+ T cells increased in mice immunized with neuroendocrine cells. IL-2 and IL-10 increased in mice that received untreated A549 cells, suggesting that the immune system mounts a regulated response against adenocarcinoma, which did not occur with A549NED cells. Cocultures demonstrated the cytotoxic capacity of PBMCs when confronted with A549 cells, while in the presence of neuroendocrine cells they not only were unable to show cytolytic activity, but also lost viability. Neuroendocrine differentiation seems to mount less of an immune response when injected in mice, which may contribute to the poor prognosis of cancer patients affected by this pathology.

The differentially expressed gene signatures of the Cullin 3-RING ubiquitin ligases in neuroendocrine cancer.

Cullin-RING ubiquitin E3 ligase (CRLs) composed of four components including cullin scaffolds, adaptors, substrate receptors, and RING proteins mediates the ubiquitination of approximately 20% of cellular proteins that are involved in numerous biological processes. While CRLs deregulation contributes to the pathogenesis of many diseases, including cancer, how CRLs deregulation occurs is yet to be fully investigated. Here, we demonstrate that components of CRL3 and its transcriptional regulators are possible prognosis marker of neuroendocrine (NE) cancer. Analysis of Cancer Cell Line Encyclopedia (CCLE) through the CellMinerCDB portal revealed that expression of CRL3 scaffold Cullin 3 (CUL3) highly correlates with NE signature, and CUL3 silencing inhibited NE cancer proliferation. Moreover, subset of 151 BTB (Bric-a-brac, Tramtrack, Broad complex) domain-containing proteins that have dual roles as substrate receptors and adaptor subunits in CRL3, as well as the expression of transcription factors (TFs) that control the transcription of BTB genes were upregulated in NE cancer. Analysis using published ChIP-sequencing data in small cell lung cancer (SCLC), including NE or non-NE SCLC verified that gene promoter of candidates which show high correlation with NE signature enriched H3K27Ac. These observations suggest that CRL3 is a master regulator of NE cancer and knowledge of specifically regulated CRL3 genes in NE cancer may accelerate new therapeutic approaches.

Endometrial neuroendocrine carcinoma and undifferentiated carcinoma are distinct entities with overlap in neuroendocrine marker expression.

AIMS: Dedifferentiated endometrial carcinomas (DDECs)/undifferentiated endometrial carcinomas (UDECs) frequently harbour genomic activation of switch/sucrose non-fermentable (SWI/SNF)-complex proteins, and can show histological overlap with neuroendocrine carcinoma (NEC). The aim of this study was to compare the extent of the expression of neuroendocrine markers, SWI/SNF proteins and mismatch repair (MMR) proteins in DDEC/UDEC and NEC. METHODS AND RESULTS: The extent of expression of synaptophysin, chromogranin, CD56, ARID1A, ARID1B, SMARCA4, SMARCB1 and MMR proteins was evaluated by immunohistochemistry on 44 SWI/SNF-deficient DDECs/UDECs and 15 NECs. Thirty-three of 44 (75%) DDECs/UDECs showed expression of at least one neuroendocrine marker, with 18 of 44 (41%) expressing two or more neuroendocrine markers, whereas all 15 NECs showed expression of at least one neuroendocrine marker, with 14 of 15 (93%) expressing two or more neuroendocrine markers. Neuroendocrine marker expression in DDECs/UDECs was typically focal when present, with average extents of 17%, 4% and 8% for synaptophysin, chromogranin and CD56 in the positive cases, respectively, in contrast to 73%, 40% and 62% in the positive NEC cases, respectively. All 15 NECs showed intact expression of SWI/SNF-complex proteins, except for one that showed isolated loss of ARID1A. Thirty-eight of 44 DDECs/UDECs were MMR-abnormal (34 with loss of MLH1 and PMS2, and four with loss of PMS2 alone), whereas all NECs retained MMR protein expression. CONCLUSIONS: Our study demonstrates frequent but typically focal neuroendocrine marker expression in SWI/SNF-deficient DDECs/UDECs, whereas NECs typically express two or more neuroendocrine markers, with diffuse expression of at least one marker. ARID1B, SMARCA4 and SMARCB1 immunohistochemistry can be used to aid in the differentiation between DDEC/UDEC and NEC.

What I Learned from My Last Year with Susan: Reflections on Caregiving, Grief, and Moving Forward After My Wife's Cancer Diagnosis.

In 2018, my wife, Susan, died from an aggressive form of neuroendocrine cancer nine months after receiving her diagnosis. In this article, I share some of what I learned about living and dying from Susan with the hope that other caregivers and medical professionals providing end-of-life support might benefit from my experience. This included viewing dying in ways that I had not expected; grieving the many "small deaths" during her illness that helped prepare for the final loss; learning the important values in life; needing to find meaning and purpose in life after caregiving; experiencing guilt on different levels; and deciding on readiness to move forward with my life.

Modulation of Pancreatic Neuroendocrine Neoplastic Cell Fate by Autophagy-Mediated Death.

INTRODUCTION: Autophagic cell death in cancer cells can be mediated by inhibition of deacetylases. Although extensive studies have focused on the autophagic process in cancer, little is known about the role of autophagy in degrading cytosolic and nuclear components of pancreatic neuroendocrine neoplastic (pNEN) cells leading to cell death, thus improving the therapy of patients affected by pNEN. METHODS: 2D and 3D human pNEN and pancreatic stellate cells were treated with panobinostat and bafilomycin. Autophagy markers were detected by RT-qPCR, immunofluorescence, and Western blot. Autophagosomes were detected by electron microscopy and their maturation by real-time fluorescence of LC3B stable transfected cells. ChIP was performed at the cAMP responsive element. Immunofluorescence was performed in murine pancreatic tissue. RESULTS: We observed that pan-deacetylase inhibitor panobinostat treatment causes autophagic cell death in pNEN cells. We also found that although AMPK-α phosphorylation is counterbalanced by phosphorylated AKT, it is not capable to inhibiting autophagic cell death. However, the binding activity of the cAMP responsive element is prompted by panobinostat. Although autophagy inhibition prevented autophagosome synthesis, maturation, and cell death, panobinostat treatment induced the accumulation of mature autophagosomes in the cytosol and the nucleus, leading to disruption of the organelles, cellular digestion, and decay. Observation of autophagosome membrane proteins Beclin1 and LC3B aggregation in murine pancreatic islets indicates that autophagy restoration may also lead to autophagosome aggregation in murine insulinoma cells. A basal low expression of autophagy markers was detectable in patients affected by pNEN, and, interestingly, the expression of these markers was significantly lower in metastatic pNEN. DISCUSSION/CONCLUSION: Our study highlights that the autophagy functional restoration and prolongation of this catabolic process, mediated by inhibition of deacetylase, is responsible for the reduction of pNEN cells. Prompting of autophagy cell death could be a promising strategy for the therapy of pNEN.

The Role of Patient Support Groups in Neuroendocrine Neoplasms.

PURPOSE OF REVIEW: The purpose of this review is to establish the role patient support groups play in NENs. RECENT FINDINGS: Published data on the role and work done by these groups is extremely sparse, so the review references publications in the wider cancer advocacy context. For the purposes of the review, a survey was carried out among the members of a global umbrella organization to ascertain the level of activities undertaken in support of the NEN patient community. The concept of "support groups" has changed significantly, as these groups have evolved from patient peer-to-peer support provision to a strategic focus on improving awareness and education among all stakeholders, generating patient evidence to influence policies for access to optimal diagnostics, treatment, and care, and setting the research agenda. Today, NEN patient organizations have an instrumental role of catalysts of change across the healthcare spectrum-especially relevant in a setting of less common and not well-understood diseases, where clear pathways and guidelines are still a challenge.

Deep Membrane Proteome Profiling Reveals Overexpression of Prostate-Specific Membrane Antigen (PSMA) in High-Risk Human Paraganglioma and Pheochromocytoma, Suggesting New Theranostic Opportunity.

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors arising from chromaffin cells of adrenal medulla or sympathetic or parasympathetic paraganglia, respectively. To identify new therapeutic targets, we performed a detailed membrane-focused proteomic analysis of five human paraganglioma (PGL) samples. Using the Pitchfork strategy, which combines specific enrichments of glycopeptides, hydrophobic transmembrane segments, and non-glycosylated extra-membrane peptides, we identified over 1800 integral membrane proteins (IMPs). We found 45 "tumor enriched" proteins, i.e., proteins identified in all five PGLs but not found in control chromaffin tissue. Among them, 18 IMPs were predicted to be localized on the cell surface, a preferred drug targeting site, including prostate-specific membrane antigen (PSMA), a well-established target for nuclear imaging and therapy of advanced prostate cancer. Using specific antibodies, we verified PSMA expression in 22 well-characterized human PPGL samples. Compared to control chromaffin tissue, PSMA was markedly overexpressed in high-risk PPGLs belonging to the established Cluster 1, which is characterized by worse clinical outcomes, pseudohypoxia, multiplicity, recurrence, and metastasis, specifically including SDHB, VHL, and EPAS1 mutations. Using immunohistochemistry, we localized PSMA expression to tumor vasculature. Our study provides the first direct evidence of PSMA overexpression in PPGLs which could translate to therapeutic and diagnostic applications of anti-PSMA radio-conjugates in high-risk PPGLs.

Outcomes of Patients with Pulmonary Large Cell Neuroendocrine Carcinoma in I-IV Stage.

Background and Objectives: Large cell neuroendocrine cancer is characterised by poor prognosis. The standard of treatment is still not established. The aim of this study was to assess the predictive factors of overall survival (OS) and progression-free survival (PFS) of pulmonary large cell neuroendocrine carcinoma (LCNEC) and combined LCNEC. Materials and Methods: All patients had confirmed pathology stage I-IV disease recorded between period 2002-2018. Survival curves were estimated by Kaplan-Meier method. Uni- and multivariable analysis was conducted using Cox-regression analysis. Results: A total of 132 patients with LCNEC and combined LCNEC were included. Half of them had clinical stage IIIB/C-IV. Patients were treated with radical (n = 67, including surgery alone; resection with neo-adjuvant or adjuvant chemotherapy, radiochemotherapy, or adjuvant radiotherapy; patients treated with radiochemotherapy alone), palliative (n = 41) or symptomatic (n = 24) intention. Seventeen patients were treated with resection margin R1 or R2. Non-small cell carcinoma (NSCLC) chemotherapy (platinum-vinorelbine; PN schedule) and small-cell lung carcinoma (SCLC) chemotherapy approaches (platinum/carboplatinum-etoposide; PE/KE schedule) were administered in 20 and in 55 patients, respectively. The median (95% Confidence Interval (CI)) OS and PFS were 17 months (9.0-36.2 months) and 7 months (3.0-15.0 months), respectively. Patients treated with negative resection margin, with lower clinical stage, without lymph node metastasis, and with size of primary tumour ≤4 cm showed significantly better OS and PFS. The main risk factors with an adverse effect on survival were advanced CS and positive resection margin. Conclusions: Patients with LCNEC characterized poor prognosis. Independent prognostic factors influencing PFS were initial clinical stage and resection margin R0 vs. R1-2.

Liver transplantation for secondary liver tumours: The difficult balance between survival and recurrence.

Assessing the balance between survival and recurrence after transplantation for secondary liver tumours should be based on the type of cancer in question. For neuroendocrine liver metastases, high recurrence rates are clearly related to reduced long-term survival. For colorectal liver metastases, experience to date indicates that pulmonary recurrence alone has a modest impact on survival outcomes. Further studies focusing on this group of patients will be important for the development of this field of transplant oncology. Liver transplantation for secondary liver tumours should be implemented in accordance with stringent transplant criteria and preferably in the context of prospective trials. Expansion of the donor pool by utilising extended criteria donors and partial liver transplantation could be considered for this indication.

The radiosensitizer Onalespib increases complete remission in 177Lu-DOTATATE-treated mice bearing neuroendocrine tumor xenografts.

PURPOSE: 177Lu-DOTATATE targeting the somatostatin receptor (SSTR) is utilized for treatment of neuroendocrine tumors (NETs). Onalespib, a heat shock protein 90 (HSP90) inhibitor, has demonstrated radiosensitizing properties and may thus enhance the effect of 177Lu-DOTATATE. Consequently, the aim of this study was to assess the potential of Onalespib in combination with 177Lu-DOTATATE in vivo and to examine the toxicity profiles of the treatments. METHODS: 177Lu-DOTATATE selectivity and distribution in NET xenografts were studied using biodistribution and autoradiography. Therapeutic effects of Onalespib in combination with 177Lu-DOTATATE were studied in NET xenografts. Histological analyses were used to assess molecular effects from treatment and to establish toxicity profiles. RESULTS: Biodistribution and autoradiography confirmed the SSTR-selective tumor uptake of 177Lu-DOTATATE, which was unaffected by Onalespib treatment. Immunohistochemistry verified molecular responses to Onalespib therapy in the tumors. While Onalespib and 177Lu-DOTATATE monotherapies resulted in a 10% and 33% delay in tumor doubling time compared with control, the combination treatment resulted in a 73% delayed tumor doubling time. Moreover, combination treatment increased complete remissions threefold from 177Lu-DOTATATE monotherapy, resulting in 29% complete remissions. In addition, histological analyses demonstrated radiation-induced glomerular injury in the 177Lu-DOTATATE monotherapy group. The damage was decreased tenfold in the combination group, potentially due to Onalespib-induced HSP70 upregulation in the kidneys. CONCLUSION: Treatment with Onalespib potentiated 177Lu-DOTATATE therapy of NET xenografts with a favorable toxicity profile. Utilizing Onalespib's radiosensitizing properties with 177Lu-DOTATATE may lead to better therapeutic results in the future and may reduce unwanted side effects in dose-limiting organs.

Germline Missense Mutation of Deleted in Malignant Brain Tumor 1 (DMBT1) in Familial Mediastinal Neuroendocrine Cancer and in vitro Effects in Thyroid Cancer Cells.

BACKGROUND: Neuroendocrine tumors (NETs) rarely occur in the mediastinum and their etiology and pathogenesis are still unclear. OBJECTIVES: This study assessed inherited or de novo mutations in familial mediastinal NETs. METHOD: DNA samples from 4 patients were subjected to the whole-exome sequencing, and Sanger sequencing was used to identify Deleted in malignant brain tumor 1 (DMBT1) mutations in all 45 family members. RESULTS: All patients showed a germline DMBT1 mutation at 4971C. Sanger sequencing data showed that 4 NETs and 2 carriers in the first patient's family and 2 NETs and 4 carriers in the second patient's family, respectively, had this DMBT1 mutation. The in vitro data showed that the ectopic expression of DMBT1 reduced tumor cell viability and migration by arresting the G1/S phase of the cell cycle. CONCLUSIONS: We identified a germline missense mutation in DMBT1D1657E as a susceptibility gene for familial mediastinal NETs.

Clinicopathologic analysis of primary gastroenteropancreatic poorly differentiated neuroendocrine carcinoma; A ten year retrospective study of 68 cases at Moffit Cancer Center.

OBJECTIVE: To assess clinicopathological characteristics of primary gastro-entero-pancreatic poorly differentiated neuroendocrine carcinomas (GEP-PDNECAs) and evaluate overall survival in patients treated with systemic platinum and etoposide therapy. METHODS: A detailed retrospective review of clinico-pathologic data (1999-2009) on 68 consecutive adult patients with primary GEP-PDNECAs was carried out, from H Lee Moffit Cancer Center and Research Institute, Tampa, Florida; USA, based on electronic patient records, specialty consultation files, tumor registry, social security index and pathology archives. All available tumor slides were reviewed and subtyped by neuro-endocrine pathologists. Clinicopathologic data and patient survival were analyzed. RESULTS: Of 68 patients 41 were males and 27 females with a mean age of 42 years (range: 25-76 years). Regarding the site of origin, 39 patients were of the colorectal location, 19 from the pancreas, 04 from small intestines, 03 from stomach and 03 were multi-focal from colon, small intestine and pancreas. Sixty three of 68 (93%) patients presented with lymph node/distant metastases. Of 68 tumors 37 (54%) were classified as small cell carcinoma (SCCA), 16 (24%) large cell carcinoma (LCCA), 5 (7%) mixed small and large cell (MSLCCA) and 10 (15%) poorly differentiated carcinoma with neuroendocrine features (PDCA-NEF). Neuroendocrine differentiation was confirmed by positivity for chromogranin in 38/65 (55%), synaptophysin in 62/67 (92%) and CD56 in 17/21 (81%) cases. One neuroendocrine marker was positive in 22/68 (32%), 2 in 40/68 (59%) and all 3 were positive in 9/68 (13%) cases. Fifty-eight of 68 (85%) patients were treated with platinum and etoposide. Overall patient survival at 1, 3 5 and 10 years was 85%, 40%, 16% and 1.5% respectively. Patient survival was independent of age (r= 0.1022), sex (r= -0.909) and histologic tumor subtype (r=0.1028) (p= 0.128) but was related to distant metastases (r=0.306; p=0.0383). CONCLUSIONS: GEP-PDNECA occurred in many part of the GI tract, most commonly in the colorectal region. Positivity of neuroendocrine markers was variable, which helped to confirm neuro-endocrine differentiation and to avoid under-diagnosis of GEP-PDNECA, especially in metastatic setting. Overall prognosis of GEP-PDNECA patients following platinum and etoposide therapy in our series was relatively favorable but remained poor in the presence of distant metastases.

The Oncolytic Herpes Simplex Virus Talimogene Laherparepvec Shows Promising Efficacy in Neuroendocrine Cancer Cell Lines.

Metastatic neuroendocrine cancer still constitutes a palliative situation, lacking promising treatment options. Oncolytic virotherapy, a novel type of virus-based immunotherapy, lyses tumor cells using genetically engineered viruses thereby activating the immune system to induce an optimized antitumor response which could bring down tumor masses to a stage of minimal residual tumor disease. The oncolytic vector talimogene laherparepvec (T-VEC, herpes simplex virus [HSV] type 1) has already shown excellent safety profiles in clinical studies and has become the first ever FDA/EMA-approved oncolytic virus (OV). This work presents a first preclinical assessment of this state-of-the-art OV, using a panel of human neuroendocrine tumor/neuroendocrine carcinoma (NET/NEC) cell lines. Cytotoxicity, transgene expression, and viral replication patterns were studied. Furthermore, the antiproliferative activity was compared to the one of mTOR inhibitor Everolimus and also interactions between the OV and Everolimus were evaluated. Moreover, virostatic effects of ganciclovir (GCV) on replication of T-VEC were assessed and electron microscopic pictures were taken to comprehend viral envelopment and details of the replication cycle of T-VEC in human neuroendocrine cancer. It could be shown that T-VEC infects, replicates in, and lyses human NET/NEC cells exhibiting high oncolytic efficiencies already at quite low virus concentrations. Interestingly, Everolimus was not found to have any relevant impact on rates of viral replication, but no additive effects could be proved using a combinatorial therapy regimen. On the other hand, GCV was shown to be able to limit replication of T-VEC, thus establishing an important safety feature for future treatments of NET/NEC patients. Taken together, T-VEC opens up a promising novel treatment option for NET/NEC patients, warranting its further preclinical and clinical development.

Repeat liver resection for pure large cell neuroendocrine carcinoma of the gallbladder: a favorable outcome.

BACKGROUND: The pure large cell type is a rare variant of primary neuroendocrine carcinoma of the gallbladder. Few reports have mentioned extended survival. Although a multimodal treatment has been described in the treatment of such rare disease, redo liver resection has not yet been mentioned. CASE REPORT: A 67-year-old lady was found to have poorly differentiated, high grade, pure large cell neuroendocrine tumor of the gallbladder after cholecystectomy for gallstones. After the diagnosis, staging workup showed a lesion in segment IVB/V of the liver, and chromogranin was elevated (982 mcg/L). The patient underwent central inferior hepatectomy and wedge excision of a lesion in segment III (discovered intra-operatively), with hilar lymphadenectomy. Three months after the first liver resection, she developed a new liver lesion II/III and underwent left lateral liver resection. The patient remained disease-free for 4 months following the second liver resection but then developed recurrent liver disease and was started on chemotherapy. Further progression led to multi-organ failure and death at 26 months from initial diagnosis. CONCLUSION: This is the first reported repeat liver resection in such a rare disease that has led to extended overall survival. We suggest that a group of selected patients with this rare malignancy, and liver-limited disease, may benefit from repeated liver resection.

Combined sublethal irradiation and agonist anti-CD40 enhance donor T cell accumulation and control of autochthonous murine pancreatic tumors.

Tumor-reactive T lymphocytes can promote the regression of established tumors. However, their efficacy is often limited by immunosuppressive mechanisms that block T cell accumulation or function. ACT provides the opportunity to ameliorate immune suppression prior to transfer of tumor-reactive T cells to improve the therapeutic benefit. We evaluated the combination of lymphodepleting whole body irradiation (WBI) and agonist anti-CD40 (αCD40) antibody on control of established autochthonous murine neuroendocrine pancreatic tumors following the transfer of naïve tumor-specific CD8 T cells. Sublethal WBI had little impact on disease outcome but did promote T cell persistence in the lymphoid organs. Host conditioning with αCD40, an approach known to enhance APC function and T cell expansion, transiently increased donor T cell accumulation in the lymphoid organs and pancreas, but failed to control tumor progression. In contrast, combined WBI and αCD40 prolonged T cell proliferation and dramatically enhanced accumulation of donor T cells in both the lymphoid organs and pancreas. This dual conditioning approach also promoted high levels of inflammation in the pancreas and tumor, induced histological regression of established tumors, and extended the lifespan of treated mice. Prolonged survival was entirely dependent upon adoptive transfer, but only partially dependent upon IFNγ production by donor T cells. Our results identify the novel combination of two clinically relevant host conditioning approaches that synergize to overcome immune suppression and drive strong tumor-specific T cell accumulation within well-established tumors.