Neuroendocrine Tumor Cells Research Articles

1403P - Efficacy of immune check-point inhibitors (ICPi) in large cell neuroendocrine tumours of lung (LCNET)

BackgroundLittle is known regarding the efficacy of ICPi in LCNET. MethodsThirty seven consecutive patients (pts) with advanced LCNET were selected from the Davidoff Cancer Center database. These were divided into Groups A1 (pts treated with ICPi, n-23) and A2 (pts not treated with ICPi, n-14). Another cohort of advanced non-small cell lung cancer (NSCLC) pts treated with nivolumab at five Israeli cancer centers in 2015-2016 was chosen as a comparator (Group B, n-270). ORR, PFS with ICPi in Group A1 were assessed (RECIST 1.1), OS with ICPi was compared between Groups A1 and B. OS since advanced disease diagnosis (OSDx) was compared between Groups A1 and A2. ResultsBaseline pts characteristics are presented in the table. In Group A1* (n-21, 2 pts receiving combined ICPi + chemotherapy were excluded), ORR and median PFS with ICPi were 33%, and 4.2 months (95% CI, 2.4-8.1), respectively. With median follow-up since start of ICPi of 6.2 months [IQR 2.2-12.1] and 4.9 months [IQR 2.3-8.9] in Groups A1* and B, respectively, 52% of pts in Group A1* and 64% of pts in Group B had died. Median OS with ICPi comprised 11.8 months (95% CI, 3.7-NR) and 6.9 months (95% CI, 5.5-8.1) in Groups A1* and B, respectively (p-0.23). Median OSDx was 14.5 months (95% CI, 10.1-38.9) and 10.3 months (95% CI, 2.6-NR), in Groups A1 and A2, respectively (p-0.54). Abbreviations: Tx- treatment, N – nivolumab, P-pembrolizumab, A- atezolizumab.Table: 1403P Baseline patients characteristicsTable: 1403P Baseline patients characteristicsGroup A1* (n-21)Group B (n-270)p valueAge (median, range), y62 (45-77)67 (40-99)0.004Gender, %0.09F5233M4867Smoking, %1Smokers8677Never smokers1414NA9ECOG PS at ICPi, %0.060/167462-42447NA97Previous Tx lines, %0.20106180662-41025NA10 (3)ICPi type: N/P/A/other, %62/9/20/9100/0/0/0NA ConclusionsIn advanced LCNET, ICPi outcomes are comparable to the outcomes observed in advanced NSCLC. Future prospective research is needed to clarify the impact of ICPi on OS in LCNET. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureA. Zer: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: AstraZeneca, Roche, BMS, MSD, BI, TAKADA. E. Dudnik: Research grant / Funding (self): Roche, Boehringer Ingelheim; Advisory / Consultancy: Boehringer Ingelheim, Roche, AstraZeneca, Pfizer, MSD, BMS, Novartis, Takeda. All other authors have declared no conflicts of interest.

DIFFUSE SUBCUTANEOUS NODULES AS A FIRST SIGN OF A METASTATIC PULMONARY NEUROENDOCRINE TUMOR

SESSION TITLE: Monday Fellow Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM INTRODUCTION: Pulmonary neuroendocrine tumors are rare tumors that arise from cells of the endocrine and nervous systems with an incidence rate of 2/100,000 population/year in the United States, comprising 2% of all primary lung cancers. The most common described sites of metastases from Carcinoid tumors are liver , bone , and mediastinal lymph nodes . Subcutaneous metastases from carcinoid tumors are very rare. The behavior of these tumors depends upon their location within the lungs, whether they secrete hormones, or if they have metastasized. This tumors comprise a spectrum of progression, including: low grade neuroendocrine tumors , intermediate grade neuroendocrine tumors and high grade neuroendocrine tumors (large cell neuroendocrine tumors and small cell carcinomas) respectively. CASE PRESENTATION: A 72-year-old latin american female with a past medical history of breast cancer that was previously treated with chemotherapy and radiotherapy 10 years ago. Patient came to the institution due to multiple skin progressively painful enlarged skin nodules, fatigue, generalized weakness and melena of several days of evolution. Physical examination revealed multiple skin nodules measuring from 1 to 4 cm in diameter with the largest measuring 3 x 4 cm in the left neck area extremely tender and firm. A biopsy was performed with histopathology consistent with a carcinoid tumor with moderate amount of cytoplasm and eccentric nuclei. Immunohistochemistry of the neoplastic cells exhibited similar positive staining for the neuroendocrine markers chromogranin A and synaptophysin with positive markers for CD56, pankeratin with a Ki67 of 70%. Staining of the neoplastic cells also was positive for thyroid transcription factor 1 (TTF-1) . These results were consistent with cutaneous metastasis from pulmonary carcinoid tumor by which same cells were also seen by stomach biopsy of nodules present as well. DISCUSSION: Cutaneous metastases of internal malignancies are more common from carcinomas of the lungs, gastrointestinal tract, and breasts. The histology of cutaneous carcinoid metastases typically resembles the primary lesion. However, identifying source is a major role in this cases. Occasionally, the cutaneous metastasis will develop directly over the underlying malignancy but thats not the case in the majority of cases. Thats were histologic stains and cells characteristics play a major role. Our case of cutaneous metastasis of a carcinoid tumor presented as multiple tender subcutaneous nodules. The histology of the lesion was consistent with the known carcinoid tumor of the lung. CONCLUSIONS: Even though neuroendocrine tumors are rare, obtaining an concise clinical history , addressing risk factors and pertinent findings of medical presentation with the appropriate immunohistochemical panels is the cornerstone of this challenging cases when primary site is in doubt. Reference #1: Pulmonary neuroendocrine (carcinoid) tumors: European Neuroendocrine Tumor Society expert consensus and recommendations for best practiceCaplin ME, Baudin E, Ferolla P, et al. Reference #2: Primary pulmonary carcinoid tumor: a long-term single institution experience/Primary pulmonary carcinoid tumor.Ryan F. Herde, MD, MS1, Kristine E. Kokeny, MD2, Chakravarthy B. Reddy, MD3, Wallace L. Akerley, MD4, Nan Hu, PhD5, Jonathan P. Boltax, MD3, and Ying J. Hitchcock, MD2. Reference #3: Cutaneous Metastasis of a Pulmonary Carcinoid Tumor Cutis. 2017 May;99(5):E13-E15 DISCLOSURES: No relevant relationships by Christian Castillo Latorre, source=Web Response No relevant relationships by Michael Cruz, source=Web Response No relevant relationships by Omar Mendez Melendez, source=Web Response No relevant relationships by Kelvin Rivera Manzano, source=Web Response

The HSP90 inhibitor onalespib potentiates 177Lu‑DOTATATE therapy in neuroendocrine tumor cells.

177Lu-DOTATATE was recently approved for the treatment of somatostatin receptor (SSTR)-positive neuroen-docrine tumors (NETs). However, despite impressive response rates, complete responses are rare. Heat shock protein 90 (HSP90) inhibitors have been suggested as suitable therapeutic agents for NETs, as well as a potential radiosensitizers. Consequently, the aim of this study was to investigate whether the HSP90-inhibitor onalespib could reduce NET cell growth and act as a radiosensitizer when used in combination with 177Lu-DOTATATE. The NET cell lines BON, NCI-H727 and NCI-H460, were first characterized with regards to 177Lu-DOTATATE uptake and sensitivity to onalespib treatment in monolayer cell assays. The growth inhibitory effects of the monotherapies and combination treatments were then examined in three-dimensional multicellular tumor spheroids. Lastly, the molecular effects of the treatments were assessed. 177Lu-DOTATATE uptake was observed in the BON and NCI-H727 cells, while the NCI-H460 cells exhibited no detectable uptake. Accordingly, 177Lu-DOTATATE reduced the growth of BON and NCI-H727 spheroids, while no effect was observed in the NCI-H460 spheroids. Onalespib reduced cell viability and spheroid growth in all three cell lines. Furthermore, the combination of onalespib and 177Lu-DOTATATE exerted synergistic therapeutic effects on the BON and NCI-H727 spheroids. Western blot analysis of BON spheroids revealed the downregulation of epidermal growth factor receptor (EGFR) and the upregulation of γ H2A histone family member X (γH2AX) following combined treatment with onalespib and 177Lu-DOTATATE. Moreover, flow cytometric analyses revealed a two-fold increase in caspase 3/7 activity in the combination group. In conclusion, the findings of this study demonstrate that onalespib exerts antitumorigenic effects on NET cells and may thus be a feasible treatment option for NETs. Furthermore, onalespib was able to synergistically potentiate 177Lu-DOTATATE treatment in a SSTR-specific manner. The radiosensitizing mechanisms of onalespib involved the downregulation of EGFR expression and the induction of apoptosis. Consequently, the combination of onalespib and 177Lu-DOTATATE may prove to be a promising strategy with which to improve therapeutic responses in patients with NETs. Further studies investigating this strategy in vivo regarding the therapeutic effects and potential toxicities are warranted to expand these promising findings.

Detection of NRG1 Gene Fusions in Solid Tumors.

NRG1 gene fusions are rare but potentially actionable oncogenic drivers that are present in some solid tumors. Details regarding the incidence of these gene rearrangements are lacking. Here, we assessed the incidence of NRG1 fusions across multiple tumor types and described fusion partners. Tumor specimens submitted for molecular profiling at a Clinical Laboratory Improvement Amendments (CLIA)-certified genomics laboratory and that underwent fusion testing by anchored multiplex PCR for targeted RNA sequencing were retrospectively identified. The overall and tumor-specific incidence was noted, as was the specific fusion partner. Out of 21,858 tumor specimens profiled from September 2015 to December 2018, 41 cases (0.2%) harbored an NRG1 fusion. Multiple fusion partners were identified. Fusion events were seen across tumor types. The greatest incidence was in non-small cell lung cancer (NSCLC, 25), though this represented only 0.3% of NSCLC cases tested. Other tumor types harboring an NRG1 fusion included gallbladder cancer, renal cell carcinoma, bladder cancer, ovarian cancer, pancreatic cancer, breast cancer, neuroendocrine tumor, sarcoma, and colorectal cancer. NRG1 fusions can be detected at a low incidence across multiple tumor types with significant heterogeneity in fusion partner.See related commentary by Dimou and Camidge, p. 4865.

Intrathecal lentivirus-mediated RNA interference targeting nerve growth factor attenuates myocardial ischaemia–reperfusion injury in rat

BackgroundNerve growth factor (NGF) has been implicated in hyperalgesia by sensitising nociceptors. A role for NGF in modulating myocardial injury through ischaemic nociceptive signalling is plausible. We examined whether inhibition of spinal NGF attenuates myocardial ischaemia–reperfusion injury and explored the underlying mechanisms. MethodsIn adult rats, lentivirus-mediated short-hairpin RNA targeted at reducing NGF gene expression (NGF-shRNA) or a transient receptor potential vanilloid 1 (TRPV1) antagonist (capsazepine) was injected intrathecally before myocardial ischaemia–reperfusion. Infarct size (expressed as the ratio of area at risk) and risk of arrhythmias were quantified. Whole-cell clamp patch electrophysiology was used to record capsaicin currents in primary dorsal root ganglion neurones. The co-expression of substance P (SP) and calcitonin gene-related peptide (CGRP), plus activation of TRPV1, protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) were also quantified. ResultsNGF levels increased by 2.95 (0.34)-fold in dorsal root ganglion and 2.12 (0.27)-fold in spinal cord after myocardial ischaemia–reperfusion injury. Intrathecal injection of NGF-shRNA reduced infarct area at risk from 0.58 (0.02) to 0.37 (0.02) (P<0.01) and reduced arrhythmia score from 3.67 (0.33) to 1.67 (0.33) (P<0.01). Intrathecal capsazepine was similarly cardioprotective. NGF-shRNA suppressed expression of SP/CGRP and activation of Akt/ERK and TRPV1 in spinal cord. NGF increased capsaicin current amplitude from 144 (42) to 840 (132) pA (P<0.05), which was blocked by the TRPV1 antagonist 5′-iodoresiniferatoxin. Exogenous NGF enhanced capsaicin-induced Akt/ERK and TRPV1 activation in PC12 neuroendocrine tumour cells in culture. ConclusionsSpinal NGF contributes to myocardial ischaemia–reperfusion injury by mediating nociceptive signal transmission.

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

BackgroundThe 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 reportA 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.ConclusionThis 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.

Effect of the Tryptophan Hydroxylase Inhibitor Telotristat on Growth and Serotonin Secretion in 2D and 3D Cultured Pancreatic Neuroendocrine Tumor Cells

Serotonin, a biologically active amine, is related to carcinoid syndrome in functioning neuroendocrine tumors (NETs). Telotristat ethyl is a novel inhibitor of the tryptophan hydroxylase (TPH), a key enzyme in the production of serotonin. While its use in patients with carcinoid syndrome and uncontrolled diarrhea under somatostatin analogs (SSAs) has been recently approved, in vitro data evaluating its effectiveness are lacking. For this reason, we aimed to evaluate the effect of telotristat as monotherapy, and in combination with SSAs, on proliferation and secretion in a NET cell line model. The human pancreatic NET cell lines BON-1/QGP-1 were used as 2D and 3D cultured models; somatostatin receptor and TPH mRNA expression, as well as the potential autocrine effect of serotonin on tumor cell proliferation using a 3D culture system were evaluated. Telotristat decreased serotonin production in a dose-dependent manner at a clinically feasible concentration, without affecting cell proliferation. Its combination with pasireotide, but not with octreotide, had an additive inhibitory effect on serotonin secretion. The effect of telotristat was slightly less potent, when BON-1 cells were co-treated with octreotide. Octreotide and pasireotide had no effect on the expression of TPH. Telotristat did not have an effect on mRNA expression of somatostatin receptor subtypes. Finally, we showed that serotonin did not have an autocrine effect on NET cell proliferation on the 3D cell model. These results suggest that telotristat is an effective drug for serotonin inhibition, but the effectiveness of its combination with SST₂ (somatostatin receptor subtype 2)-preferring SSA should be evaluated in more detail.

Physiopathological Premises to Nuclear Medicine Imaging of Pancreatic Neuroendocrine Tumours.

Pancreatic Neuroendocrine Tumors (P-NETs) are a challenge in terms of both diagnosis and therapy; morphological studies need to be frequently implemented with nonstandard techniques such as Endoscopic Ultrasounds, Dynamic CT, and functional Magnetic Resonance. The role of nuclear medicine, being scarcely sensitive F-18 Fluorodeoxyglucose, is mainly based on the over-expression of Somatostatin Receptors (SSTR) on neuroendocrine tumor cells surface. Therefore, SSTR can be used as a target for both diagnosis, using radiotracers labeled with gamma or positron emitters, and therapy. SSTRs subtypes are capable of homo and heterodimerization in specific combinations that alter both the response to ligand activation and receptor internalization. Although agonists usually provide efficient internalization, also somatostatin antagonists (SS-ANTs) could be used for imaging and therapy. Peptide Receptor Radionuclide Therapy (PRRT) represents the most successful option for targeted therapy. The theranostic model based on SSTR does not work in insulinoma, in which different radiotracers such as F-18 FluoroDOPA or tracers for the glucagon-like peptide-1 receptor have to be preferred.

Enterochromaffin-like cell neuroendocrine tumor associated with parietal cell dysfunction

Enterochromaffin-like cell neuroendocrine tumor associated with parietal cell dysfunction

Abstract 1123: Bcl-xL promotes metastasis via a novel nuclear function

Abstract Cancer cells often evade apoptosis through upregulation of anti-apoptotic proteins and/or downregulation of pro-apoptotic proteins. Bcl-xL, a negative regulator of mitochondria-mediated apoptosis, is frequently overexpressed in cancer cells. Bcl-xL has long been known for its function in regulating apoptosis during embryonic development and in pathological conditions. Any role that Bcl-xL might play in tumor metastasis has been ascribed to its anti-apoptotic function; i.e. Bcl-xL may increase metastasis by lending survival advantage to the tumor cells during the course of metastasis. However, we have demonstrated that Bcl-xL’s metastatic function is independent of its canonical anti-apoptotic activity and instead requires a novel nuclear function in cancer. We found that Bcl-xL promotes migration, even when cells are defective in mitochondria-mediated apoptosis. Consistently, Bcl-xL mutants lacking anti-apoptotic activity can still promote migration, induce epithelial-mesenchymal transition (EMT), upregulate TGFβ, and increase migration and invasion of pancreatic neuroendocrine tumor cells and breast cancer cells. Importantly, our data demonstrated that forcible localization of Bcl-xL outside the nucleus impairs its metastatic function. As a mitochondrial membrane protein in healthy cells, Bcl-xL’s transmembrane domain prevents its nuclear import. This suggests that Bcl-xL enters the nucleus by an active nuclear transport. We hypothesized that unique transporters likely exist so as to transport this normally mitochondria membrane-bound Bcl-xL protein to the nucleus. By using immunoprecipitation in combination with mass spectrometry, we identified a novel interacting partner of Bcl-xL. We are investigating whether this protein transports Bcl-xL into the nucleus to promote metastasis. Citation Format: Tiantian Zhang, Sha Li, Joseph Na, Soyoung Chi, George Zhang, Yi-Chieh Nancy Du. Bcl-xL promotes metastasis via a novel nuclear function [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1123.

Interaction between somatostatin analogues and targeted therapies in neuroendocrine tumor cells.

Somatostatin analogues (SSA) represent the standard of care for symptom control in patients with functional gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). In addition, SSA exert significant anti-proliferative effects in mid-gut and pancreatic NET (PanNET). In parallel, molecularly targeted therapies (MTT) have been shown to improve progression free survival (PFS) in patients with PanNET. However, due to either primary or acquired resistance to MTT, their impact on overall survival (OS) remains unclear. To date, various hypotheses exist to explain differences in patient responsiveness to SSA and MTT. However, data addressing one of the most pivotal questions, whether combining SSA with novel MTT will result in synergistic or additive efficacy compared to monotherapy, are lacking. The aim of this study is to characterize the interaction, optimal sequence and dosing of SSA-based and molecularly targeted therapies in PanNET. Somatostatin receptor subtypes 1–5 (SSTR) were evaluated in the neuroendocrine cell lines Bon1, QGP1 and Ins-1 via immunoblot and qRT-PCR. The impact of the SSA-analogue lanreotide alone or in combination with the MTT sunitinib, everolimus and regorafenib on intracellular signalling, hormone secretion and cell proliferation was determined in cell lysates and supernatants. In addition, synergistic effects of SSA and MTT in various sequential therapeutic approaches were investigated. SSTR were differently expressed in the examined neuroendocrine tumor cell lines. SSTR modulation via lanreotide moderately influenced proliferation, mainly via modulating AKT and ERK signalling, which was paralleled by decreased chromogranin A (CgA) expression and secretion. Interestingly, MTT treatment with regorafenib upregulated the expression of SSTR-2 and -5, while sunitinib and everolimus did not significantly alter SSTR expression. Cell viability was significantly reduced by all MTT, with regorafenib exerting the most significant effects. However, compared to the marked effects of MTT alone, synergistic effects of combined MTT and lanreotide treatment were only modest and time- and dose-dependent. SSTR are differentially expressed in various NEN cell lines. Their expression is influenced by MTT treatment. Various sequential or simultaneous combinations of lanreotide and MTT did not lead to significant synergistic effects.

METASTATIC NEUROENDOCRINE PROSTATE CANCER, AN AGGRESSIVE PROSTATE MALIGNANCY: A REPORT OF TWO CASES WITH ORAL MANIFESTATIONS

Objectives Neuroendocrine prostate cancer (NEPC) is a lethal prostate malignancy with a median survival of less than 1 year from time of detection. NEPC can occur de novo or more commonly as a treatment emergent phenomenon (t-NEPC). t-NEPC occurs in a subset of patients with metastatic-castration resistant prostate cancer. Two cases of t-NEPC with oral manifestations are presented highlighting the pathologic features and the varied clinical context in which these lesions presented. Patients and Methods Case 1) A 79 year-old man with a history of prostate adenocarcinoma undergoing hormone treatment presented with a fungating mass of the right maxilla and palate, clinically suspicious for squamous cell carcinoma. Biopsy revealed a high grade neuroendocrine carcinoma. Case 2) A 76 year-old man with a history of metastatic prostate adenocarcinoma receiving zoledronic acid and denosumab treatment for bony metastases, presented with mandibular fracture. A segmental resection without reconstruction with debridement was performed with a clinical diagnosis of medication-related osteonecrosis of the jaw (MRONJ). The pathology revealed a high grade neuroendocrine cell tumor. Both cases were positive for neuroendocrine markers chromogranin, synaptophysin, and CD56, and stained negative for prostate specific antigen (PSA) and prostate specific acid phosphatase (PSAP). Both tumors demonstrated a proliferative index (Ki-67) of 60-70%. An extended panel of immunostains appeared to eliminate other entities from consideration. Conclusions Awareness of t-NECP is of importance to correctly diagnosis the entity, recognizing that tumor markers such as PSA and PSAP are negative, and standard serum markers for prostate carcinoma may be stable or show no increase with progression of disease. Neuroendocrine carcinoma in the setting of medication related osteonecrosis of the jaw in a patient with prostate carcinoma needs to be included in the differential diagnosis.

Comparison of four DLL3 antibodies performance in high grade neuroendocrine lung tumor samples and cell cultures

BackgroundSmall cell lung cancer (SCLC) is usually diagnosed in the advanced stage. It has a very poor prognosis, with no advancements in therapy in the last few decades. A recent phase 1 clinical study, using an antibody-drug conjugate directed against DLL3, showed promising results. A prerequisite for this therapy is an immunohistochemical test for DLL3 expression. The antibody used in the clinical trial was bound to a specific platform, which is not available in all pathology laboratories. In this study, the expression of DLL3 was analyzed using different DLL3 antibodies in high-grade neuroendocrine tumors of the lung and cell cultures. Additionally, correlation of DLL3 expression with Rb1 loss and TP53 mutation was evaluated.MethodsThe study cohort consisted of surgically resected cases, 24 SCLC and 29 large cell neuroendocrine carcinoma (LCNEC), from which tissue microarrays (TMAs) were constructed. The validation cohort included 46 SCLC samples, mostly small biopsies. Additionally, well-characterized SCLC cell lines were used. Immunohistochemical analysis was performed using four different DLL3 antibodies, as well as TP53 and Rb1 antibodies. Expression was evaluated microscopically and manually scored.ResultsThe comparison of all DLL3 antibodies showed poor results for the overall agreement, as well as positive and negative agreement. Differences were observed regardless of the applied cut-off values and the tumor type. The antibody used in the clinical trial was the only which always positively stained the tumor cells obtained from cell cultures with known DLL3 expression and was negative on cells that did not express DLL3. There was no correlation between p53 and DLL3 expression in SCLC and LCNEC. RB1 loss in SCLC showed statistical significant correlation with the DLL3 positivity (p = 0.037), while no correlation was found in LCNEC.ConclusionThe DLL3 antibody used in the clinical trial demonstrated superiority in the detection of DLL3 expression. Cell cultures, which can be used for DLL3 antibodies as positive and negative probes, were established. Evidence of DLL3 expression in high proportions of patients with LCNEC might provide basis for studies of new therapy options in this group of patients.

Response rate to chemotherapy after disease progression with anti-PD-1/PD-L1 in metastatic cancer.

e14088 Background: The checkpoint inhibitor (CPI) immunotherapy class of drugs is redefining how we treat cancer. The US FDA has approved CPI drugs as 1st, 2nd or salvage line after progression on conventional chemotherapy (CTX) for multiple cancers including melanoma, lung, bladder and other cancers. However, many questions remain regarding optimal treatment post-progression. Indeed, it has been noted that the patterns of response and relapse to CPI agents are quite different from those of standard cytotoxic agents and that response to CTX AFTER CPI may be different than in the de novo setting. The purpose of this retrospective analysis is to evaluate the activity (response rate (RR), response duration (DOR) and progression free survival (PFS)) of subsequent CTX after disease progression following treatment with CPI. Methods: In this analysis, patients (pts) were enrolled under an IRB approved waiver of consent. We identified pts treated with CPI agents between Jan, 2011 and Dec, 2018 at a multi-site community cancer program who received subsequent CTX as a result of disease progression (PD). We assessed the RECIST RR to subsequent therapy, DOR from onset of response, and PFS from the onset of post CPI CTX, identifying index lesions from the most recent pre-treatment anatomic scan. Results: A total of 47 cases satisfying the above criteria were found; 31 NSCLC, 8 melanoma, 1 SCLC, 1 GEJ, 1 gastric, 2 head/neck, 1 large cell neuroendocrine tumor, 2 bladder cancer. 25 pts had PD as best response to post-CPI CTX. 9 pts (19%) achieved a partial response (PR) with a median DOR of 99 days. 22 pts achieved a PR or stable disease (SD) for a clinical benefit (CB) rate of 47%. The median duration of CB was 92 days. Of the 9 patients who achieved PR, 5/6 had achieved response to CTX prior to CPI . The median PFS for the entire cohort was 97 days. Conclusions: While an expected RR could not be calculated in this heterogenous group of pts, the number and degree of responses suggests CPI possible “priming” that may enhance response to CTX. Post-CPI CTX may be of value and in this retrospective study of a heterogenous group of pts, responses may be more frequent than expected. A larger further study is warranted.

Effects of Ketoconazole on ACTH-Producing and Non-ACTH-Producing Neuroendocrine Tumor Cells

Prolonged remission of hypercortisolism with steroidogenesis inhibitors has been described in patients with ectopic adrenocorticotropic hormone (ACTH) syndrome. The anti-proliferative and pro-apoptotic effect of ketoconazole in human cancer cells was previously suggested. The aim of this study was to explore the effects of ketoconazole on ACTH-producing and non-ACTH-producing neuroendocrine tumor (NET) cell lines. The effects of ketoconazole alone, and in combination with somatostatin analogs, were evaluated in two human cell lines: DMS-79 (ectopic ACTH-producing small cell lung carcinoma) and BON-1 (human pancreatic NET). Total DNA measurement, apoptosis, cell cycle, chromogranin A (CgA)/proopiomelanocortin (POMC) expression by qRT-PCR, serotonin, CgA, and ACTH secretion assays were performed. In both cell lines, ketoconazole significantly suppressed cell growth and colony formation in a dose and time-dependent manner. The effect in DMS-79 was primarily cytotoxic, while it was more apoptotic in BON-1 cells. Ketoconazole also induced increase in G0/G1 phase in both cell lines and arrest in phase G2/M of BON-1 cells. Ketoconazole did not affect the secretion of serotonin, CgA, ACTH, or the mRNA expression of CgA and POMC. Decreased serotonin secretion was observed after the combination treatment with pasireotide. These results suggest a direct effect of ketoconazole on cell proliferation, apoptosis, and cell cycle in both ACTH- and non-ACTH-producing NET cells.

A new generation somatostatin-dopamine chimeric analogue exerts potent antitumoral actions on primary pituitary neuroendocrine tumor cells

A new generation somatostatin-dopamine chimeric analogue exerts potent antitumoral actions on primary pituitary neuroendocrine tumor cells

SUN-LB068 Ectopic Cushing Syndrome Due to a Metastatic Neuroendocrine Tumor Treated with Metyrapone

Introduction: We describe a patient with a non-secretory low grade neuroendocrine tumor that transformed into a high grade carcinoma causing Cushing syndrome that was medically managed with metyrapone. Clinical Case: A 53 year old woman with a history of widely metastatic neuroendocrine tumor for 5 years was treated with somatostatin analogues, multiple chemotherapeutic agents, radiation therapy, and recently peptide receptor radionuclide therapy (PRRT). Some of her tumors were responding to PRRT, except that 1 month after her 3rd round of PRRT, she presented with profound muscle weakness, confusion, hypokalemia (K = 3.1 meq/L), and new onset of diabetes mellitus (glucose 319 mg/dL). Ectopic Cushing syndrome was diagnosed by ACTH of 748 pg/mL (n 7.2 - 63 pg/mL), a serum cortisol of 127 mcg/dL (n 6.7 - 22.6 mcg/dL), and a 24 hour urine free cortisol of 20,328 mcg/L (n 0 - 50 ug/24 hr). Her labs also showed pancytopenia including platelet count of 47 E3/ul (n 150 - 450 x10E3/uL). Imaging revealed growing necrotic liver metastases and thickened adrenal glands. Biopsy of the liver lesions revealed a high grade metastatic small cell neuroendocrine carcinoma with a mitotic rate of 49/10 HPF and Ki-67 of 70%. Interestingly, the neuroendocrine tumor cells in the liver biopsy did not stain for ACTH. This diverged greatly from pathology on initial diagnosis which revealed a low-grade well differentiated neuroendocrine tumor with a mitotic rate 2/10 HPF and Ki-67of 4-5%. It was clear from the patient’s clinical presentation and pathology results that her tumor had evolved into a poorly differentiated tumor secreting either ACTH and/or CRH resulting in Cushing syndrome. She was deemed a poor surgical candidate for adrenalectomy due to critical illness and advanced cancer. Elevated transaminases related to necrotic liver lesions precluded use of ketoconazole. Thus, medical therapy was initiated using metyrapone as well as spironolactone, potassium supplements, and insulin. Serum cortisol improved rapidly to 20 mcg/dl. 24 hour urine free cortisol improved to 1,129 mcg/ 24 hours with metyrapone 250mg twice daily and to 429 mcg/ 24 hours with metyrapone 250 mg every 6 hours. Her thrombocytopenia worsened with a nadir of 5 E3/ul but recovered to 127 E3/ul with continuation of metyrapone. Bone marrow biopsy performed at that time found low grade neuroendocrine tumor cells that did not stain for ACTH. Conclusion: The transformation of an indolent low grade neuroendocrine tumor to a high grade neuroendocrine carcinoma was accompanied by an ectopic Cushing syndrome. The cortisol excess was controlled rapidly and effectively with metyrapone. Thrombocytopenia was temporally related to the severe hypercortisolism and platelets improved to near normal with correction of cortisol. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

MON-318 Selective ACTH Sampling in Localizing Source of ACTH in Von Hippel Lindau Disease with Pancreatic Neuroendocrine Tumour and Renal Cell Carcinoma

Background: Cushing’s syndrome (CS) in a patient with VHL has been attributed to a number of possible causes; pancreatic NET and renal cell carcinoma. The precise location of ectopic ACTH aid enormously in the management of VHL. Clinical case: A 31-year-old woman with Type 2 diabetes and family history of VHL presented with florid features of CS in her second trimester of pregnancy. A diagnosis of ACTH dependent CS was made based on elevated 24h urinary cortisol (1122 and 2448nmol/24hr, n<150-800), midnight cortisol (1322nmol/L, n<220nmol/L) and a detectable ACTH level (18.8pg/mL, n<10pg/mL). She underwent emergency caesarean section due to pre-eclampsia at 28 week gestation. Post-delivery, her morning cortisol was 2823nmol/L (n:171-536nmol/L). MRI pituitary was reported as normal. CT abdomen showed an enlarged pancreas which was almost completely cystic and a right renal mass (3.7 X 2.6 X 4cm). Serum chromogranin A was elevated (530.2ng/mL, n:27-94). 24h urinary free metanephrine was normal. Selective ACTH sampling was done together with bilateral inferior petrosal sinus sampling to elicit source of ACTH. Increased gradient of ACTH level compared to the periphery (138.9pg/mL vs. samples from IVC:115.1 pg/mL, renal vein:100.2 pg/mL) was detected from the hepatic vein that drains the pancreas via the portal venous system. Ketoconazole and metyrapone were given to control the cortisol level close to 600nmol/L prior to surgery. Preoperatively, IV hydrocortisone 100mg was administered, with additional 50mg given every 4 hours intraoperatively. Total pancreatectomy and right nephrectomy were performed. Inotropic support was required five hours into the surgery. Hydrocortisone was tapered down to a maintenance dose of 10mg, 5mg and 2.5mg TDS over 7 days. A week after surgery, am cortisol was 103nmol/L suggesting successful removal of ectopic ACTH source. Histopathological examination identified a solid tumour (18X12X12 mm) at the pancreatic tail which stained positive to Chromogranin A, synaptophysin and weakly positive to CD56. The mitoses was 0-1/10hpf with a Ki67 index of 2%. ACTH staining was positive. The renal mass was a Grade 1 clear cell renal cell carcinoma with equivocal ACTH staining. Two months later, there was resolution of cushingoid features. DOTATE and FDG/PET scans along with close surveillance using serum Chromogranin A and 6 monthly abdominal imaging were planned. Conclusion: When managing VHL with CS, there is always a possibility of more than one source of ACTH production. In delineating the cause of CS the use of selective ACTH sampling may be considered where functional imaging (DOTATATE) is unavailable. Reference : (1) Tamura K, Nishimori I, Ito T, Yamasaki I, Igarashi H, Shuin T. Diagnosis and management of pancreatic neuroendocrine tumor in von hippel-lindau disease. World J Gastroenterol. 2010;16(36):4515-4518. doi:10.3748/wjg.v16.i36.4515

SAT-319 Long-term Follow-up of Two Unrelated Boys With SDHB-Related Malignant Paragangliomas

Background: Paragangliomas (PGLs) are rare neuroendocrine cell tumors and due to its rarity, there is no current standardized treatment and optimal long-term follow-up for metastatic disease. We report two cases of SDHB-related malignant PGL in boys with more than 5 years of follow-up. Clinical case: Patient 1 (P1) presented at the age of 13 with hypertension crisis, after a history of paroxystic tachycardia and sweating since 9. Fractionated 24-hour urinary metanephrines showed high Normetanephrine (NMT). CT showed bilateral lung lesions, the largest in right basis (6.1x5.3cm) in close contact with the 7/8th ribs and vertebrae, enlarged thoracic lymph nodes, and a 2.2 cm tumor near the left carotid. The patient went through a debulking surgery of the tumors. Patient 2 (P2) presented with abdominal pain at the age of 7. CT showed an abdominal tumor that was surgically resected. In both cases immunohistochemistry was compatible with PGL. P2 tumor was a non-secreting PGL, with high plasma chromogranin A prior to surgery. Both subsequently developed multiple bone metastases, and in case 2, additional recurrent retroperitoneal metastases. Adjuvant therapeutic 131I-MIBG, until a total dose of 900mCi (P1) and 950mCi (P2,) was performed. Over a 5- and 7-year follow-up, respectively, sustained stable disease has been documented, with control of tumor burden, despite the presence of several metastatic foci, mostly in bones. P1 has maintained mild hypertension controlled with diltiazem 30mg bid and has been annually tested for urinary NMT, which is decreasing though still mildly elevated, plus imaging (MRI and/or PET-CT). Case 2 has been clinically asymptomatic with six-monthly chromogranin A determinations currently in the normal range, and annual imaging (MIBG scintigraphy, MRI and/or PET-CT). As both cases have bone metastatic disease, 5mg intravenous zoledronic acid was recently started. Sequencing of the coding exons and exon-intron boundaries of the SDHB gene found no mutations in P1, whereas a heterozygous frameshift deletion in exon 4 was found in P2 (c393delA). In P1, complementary Multiple Ligand-Binding Probe Amplification revealed a heterozygous deletion of SDHB exon 1. P1’s mother genetic screening was negative and the father refused testing. Six P2’s relatives were found to harbor the mutation, while 3 developed PGLs so far. Conclusion: Two cases of SDHB-related malignant PGL diagnosed at early ages were presented: one apparently sporadic (P1) and one familial (P2). Despite aggressive disease, with multiple disseminated bone metastases, a long-term survival has been achieved so far, with stable disease after high cumulative I131-MIBG doses and absence of significant adverse effects. Considering the rarity of the disease especially in children, these cases significantly add to the literature regarding the long-term course of malignant PGL and treatment options.

SUN-321 Rare Case of Hypoglycemia Induced by IGF2 Secreted by an Ovarian Tumor

Introduction: Mesenchymal and epithelial tumors can produced un-cleaved IGF-2 molecules known as “big” IGF-2. These tumors are associated with elevated levels of IGF-2, which can mimic hypoglycemic events of insulin-producing islet-cell tumors by binding and activating insulin receptors. Typically plasma levels of insulin, IGF-1, and GH are low. “Big” IGF-2 molecular testing is not commercially available, however diagnosis of IGF-2 mediated hypoglycemia is based on low insulin and proinsulin in association with a IGF-2 to IGF-1 ratio >3. Clinical Case A 62 year old female with no significant past medical problems presented with 20 lb weight loss and a two month history documented symptomatic hypoglycemia episodes . Her PCP palpated a firm, non-painful mass occupying nearly her entire abdomen on physical exam. CT revealed a pelvic mass measuring 23.4 cm thought to originate from the ovary. Biopsy of the mass showed a well-differentiated neuroendocrine tumor grade 3, Ki 67 of 15%. Lab work by Endocrinology was significant for a serum glucose of 46 mg/dl, insulin <5 uIU/ml, C-peptide <1 ng/ml, cortisol 43 ug/dl, IGF-1 18 ng/ml, IGF-2 163 ng/ml (IGF1:IGF2: 9), pro-insulin 1.7 pmol/L, sulfonyl urea screen was negative, Ca 125: 230 U/ml, Ca 19-9: 7 U/ml, CEA <1 ng/ml, and chromogranin-A 598 ng/ml. Ga DOTATE scan revealed a 21 cm intra-abdominal mass with multiple peritoneal soft tissue implants consistent with a neuroendocrine tumor with peritoneal carcinomatosis. Due to persistent episodes of hypoglycemia, the patient was started on octretotide 200 mg q 8 hrs, Dexamethasone 1 mg q 3 hrs and parenteral nutrition. The patient was evaluated by surgery and deemed to inoperable due to multiple metastasis. She was then treated with cepecidobine and temozolomide with significant improvement in her glycemic control. A week later, the patient was able to be weaned off TPN and dexamethasone and was discharged home on oral diet. She was evaluated a month later as outpatient and had infrequent episodes of hypoglycemia. Conclusion This is the first case report of a patient with IGF-2 induced hypoglycemia treated with a combination of cepecidobine, temozolomide, and octreotide. While octreotide helped to improve her glycemic control by generally inhibiting hormonal secretion, likely of both IGF-2 and insulin production, final symptom relief and clinical stabilization occurred with the combination of capecitabine and temozolomide, which in vitro data has is synergistic for induction of apoptosis in neuroendocrine tumor cell lines .