High-grade Neuroendocrine Tumors Research Articles

ATP6AP2 is robustly expressed in pancreatic β cells and neuroendocrine tumors, and plays a role in maintaining cellular viability

ATP6AP2, also known as (pro)renin receptor, has been shown to be expressed in several tissues including pancreatic β cells. Whereas ATP6AP2 plays an important role in regulating insulin secretion in mouse pancreatic β cells, the expression profiles and roles of ATP6AP2 in human pancreatic endocrine cells and neuroendocrine tumor cells remain unclear. Here in this study, we investigated the expression profiles of ATP6AP2 in pancreatic endocrine cells, and found that ATP6AP2 is robustly expressed in pancreatic insulinoma cells as well as in normal β cells. Although ATP6AP2 was also expressed in low-grade neuroendocrine tumors, it was not or faintly detected in intermediate- and high-grade neuroendocrine tumors. Knockdown experiments of the Atp6ap2 gene in rat insulinoma-derived INS-1 cells demonstrated decreased cell viability accompanied by a significant increase in apoptotic cells. Taken together, these findings suggest that ATP6AP2 plays a role in maintaining cellular homeostasis in insulinoma cells, which could lead to possible therapeutic approaches for endocrine tumors.

Expert Consensus Practice Recommendations of the North American Neuroendocrine Tumor Society for the management of high grade gastroenteropancreatic and gynecologic neuroendocrine neoplasms.

High-grade neuroendocrine neoplasms are a rare disease entity and account for approximately 10% of all neuroendocrine neoplasms. Because of their rarity, there is an overall lack of prospectively collected data available to advise practitioners as to how best to manage these patients. As a result, best practices are largely based on expert opinion. Recently, a distinction was made between well-differentiated high-grade (G3) neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas, and with this, pathologic details, appropriate imaging practices and treatment have become more complex. In an effort to provide practitioners with the best guidance for the management of patients with high-grade neuroendocrine neoplasms of the gastrointestinal tract, pancreas, and gynecologic system, the North American Neuroendocrine Tumor Society convened a panel of experts to develop a set of recommendations and a treatment algorithm that may be used by practitioners for the care of these patients. Here, we provide consensus recommendations from the panel on pathology, imaging practices, management of localized disease, management of metastatic disease and surveillance and draw key distinctions as to the approach that should be utilized in patients with well-differentiated G3 neuroendocrine tumors vs poorly differentiated neuroendocrine carcinomas.

Clinical Behavior, Mutational Profile and T-Cell Repertoire of High-Grade Neuroendocrine Tumors of the Head and Neck.

Neuroendocrine carcinomas (NECs) of the head and neck (HN) account for <1% of HN cancers (HNCs), with a 5-year overall survival (OS) <20%. This is a retrospective study of HN NECs diagnosed at our institution between 2005 and 2022. Immunohistochemistry and next-generation sequencing (NGS) were used to evaluate neuroendocrine markers, tumor mutational burden (TMB), mutational profiles and T-cell receptor repertoires. Eleven patients with high-grade HN NECs were identified (male:female ratio 6:5; median age 61 (Min-Max: 31-86)): nasoethmoidal (3), parotid gland (3), submaxillary gland (1), larynx (3) and base of tongue (1). Among n = 8 stage II/IVA/B, all received (chemo)radiotherapy with/without prior surgery or induction chemotherapy, with complete response in 7/8 (87.5%). Among n = 6 recurrent/metastatic patients, three received anti-PD1 (nivolumab (2), pembrolizumab (1)): two achieved partial responses lasting 24 and 10 months. After a median follow-up of 30 and 23.5 months since diagnosis and since recurrent/metastatic, median OS was not reached. Median TMB (n = 7) was 6.72 Mut/Mb. The most common pathogenic variants were TP53, HNF1A, SMARCB1, CDKN2A, PIK3CA, RB1 and MYC. There were 224 median TCR clones (n = 5 pts). In one patient, TCR clones increased from 59 to 1446 after nivolumab. HN NECs may achieve long-lasting survival with multimodality treatment. They harbor moderate-high TMBs and large TCR repertoires, which may explain responses to anti-PD1 agents in two patients and justify the study of immunotherapy in this disease.

Metastatic niches in patients with high-grade neuroendocrine tumours: Apparent findings of matched triple-positive radiolabelled molecular probes by nuclear medicine sequence imaging

Nuclear medicine imaging of neuroendocrine neoplasm (NEN) patients could evidence cancer cell states related to glycolytic hypermetabolism, somatostatin (SST) receptors overexpression or norepinephrine (NE) transport system hyperactivity status of cancer cells profiles, according to the radiolabelled molecular probe used: fluorodeoxyglucose (FDG), octreotide (SST analogue) or the compound metaiodobenzylguanidine (NE analogue), respectively. NEN lesions with positive positron emission tomography with 18FDG (glucose analogue radiolabelled with fluoride-18) stablished a relationship with tumour aggressiveness and poorly differentiated cell morphology. Otherwise, NEN lesions evidencing somatostatin receptors (SSTR) overexpression or abnormal surface NE transporter system hyperactivity status of cancer cell profiles correlated with well differentiated cell morphology. Theoretically, the apparent correspondence between the triple-positive imaging of glycolytic hypermetabolism, SSTR overexpression and abnormal NE transporter system hyperactivity of overlapping cancer cell states in metastatic site of a NEN patient could be revealing a single tumorigenic subpopulation with a dynamic divergent differentiation potential. The complex events of metastasis progression included transdifferentiation from epithelial-to-mesenchymal to leave the primary neoplastic niche, probable as a collective migration of cancer cells, including cancer stem cells (CSCs), to circulating and reversibly transdifferentiating from mesenchymal-to-epithelial to settle in distant niches. Considering future research perspectives, we argued whether the apparent triple-positive matched correlative imaging with the radiolabelled molecular probes (glucose, SST and NE analogues) in patients’ metastatic niches could indicate potential biopsy sites to further investigation for the potential CSCs properties. We suggested that early treatment planning with lutetium-177-based peptide receptor radionuclide therapy, could provide for the blocking of poorly differentiated cell states at the point of differentiation to well differentiated cell states, and vice versa. In addition, specific individual cases should be considered for targeted-based therapy with radiolabelled-NE analogue, blocking dedifferentiation and transdifferentiation from abnormal NE transporter system hyperactivity status to SSTR overexpression cancer cell profile.

Abstract CT263: A phase Ib dose-expansion study of porustobart, an anti-CTLA-4 heavy chain only monoclonal antibody, in combination with toripalimab in patients with advanced high-grade neuroendocrine neoplasms (NENs)

Abstract Background: Porustobart (HBM4003) is a fully human heavy chain only monoclonal antibody targeting CTLA-4. In addition to blocking the CTLA-4 pathway, porustobart was engineered to deplete Treg cells by enhanced antibody-dependent cellular cytotoxicity (ADCC) that was clinically validated. The prognosis of advanced high-grade NENs is poor without standard second line treatments. 4003.6, a multi-center phase Ib study is evaluating porustobart plus toripalimab (an anti-PD-1 antibody) in advanced high-grade NENs (NCT05167071). Methods: Patients (pts) with pretreated advanced high-grade NENs received porustobart at one of the two dose levels (0.3 mg/kg and 0.45 mg/kg) plus toripalimab 240 mg every three weeks (Q3W). The primary endpoint is objective response rate (ORR) per RECIST 1.1 by investigator. Results: As of 31 Aug 2022, 21 pts had been dosed, including 15 pts with neuroendocrine carcinoma (NEC), 3 pts with grade 3 neuroendocrine tumor (G3-NET) and 3 pts with mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). 66.7% (14/21) pts received at least 2 prior lines of chemotherapy. Nine tested pts were all microsatellite stable (MSS). Median follow up time was 163 days for 0.3mg/kg dose group and 56 days for 0.45mg/kg dose group.Sixteen pts had post-baseline tumor assessments. The ORR and DCR were 37.5% and 62.5%, respectively. Median duration of response was not reached. For the 11 evaluable pts with NEC, the ORR and DCR were 36.4% and 72.7%, respectively. No significant difference in efficacy was observed between the two dose groups. Treatment-related adverse events (TRAEs) were reported in 100.0% (21/21) pts, and ≥Grade 3 TRAEs were reported in 33.3% (7/21) pts. In 0.3mg/kg dose group, 75% (6/8) pts received 5-16 cycles of study treatment, and 50% (4/8) pts experienced ≥Grade 3 TRAEs. In 0.45mg/kg dose group, 92.3% (12/13) pts received ≤4 cycles, and 23.1% (3/13) pts experienced ≥Grade 3 TRAEs. Most common (≥20%) TRAEs by pooled term were hepatic function abnormal, hyperthyroidism, rash, leukopenia, anaemia, pyrexia, hypothyroidism, neutrophil count decreased and thrombocytopenia. PK data indicated no potential interaction between porustobart and toripalimab. Increase of T cell proliferation were observed in the peripheral blood of all pts. Conclusions: Porustobart 0.3 mg/kg or 0.45 mg/kg plus toripalimab 240mg Q3W showed promising anti-tumor activity and an acceptable safety profile in pts with advanced high-grade NENs. Citation Format: Ming Lu, Panpan Zhang, Lin Shen, Kai Chen, Jianwei Yang, Lijie Song, Humphrey Gardner, Kedan Lin, Luyin Ding, Shuai Zhao, Yuan Geng, Jie Ding, Zailian Lu, Yedong Wang. A phase Ib dose-expansion study of porustobart, an anti-CTLA-4 heavy chain only monoclonal antibody, in combination with toripalimab in patients with advanced high-grade neuroendocrine neoplasms (NENs) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT263.

Abstract 5034: Targeting CXCR4 and thioredoxin reductase in high grade neuroendocrine tumors and neuroendocrine carcinomas

Abstract Introduction/Background: Atypical lung carcinoids and lung neuroendocrine carcinomas (NECs) are currently incurable. Most of these cancers express the C-X-C chemokine receptor 4 (CXCR4), making CXCR4 an attractive target for cancer diagnosis and treatment using radioligand therapy (RLT) with nuclides such as alpha emitter Pb212 conjugated to Pentixather (Pent). Alpha particles produce dense ionization tracks and damage cytosolic structures such as mitochondria, leading to the generation of reactive oxygen species such as superoxide (O2 ●−) and hydroperoxides (H2O2 and ROOH) in targeted cancer cells. The FDA approved thioredoxin reductase inhibitor, auranofin (Aur), inhibits peroxiredoxin-mediated hydroperoxide metabolism increasing cell killing in targeted cancer cells. Hypothesis: Inhibition of hydroperoxide metabolism using Aur can enhance therapeutic efficacy of alpha particle emitting 212Pb-Pent in preclinical models of lung carcinoids and NECs. Results: Clinically, IHC revealed greater than 75% of atypical carcinoids and NECs tested had moderate to high CXCR4. qRT-PCR, flow cytometry and immunohistochemistry performed on different lung carcinoid and NEC lung cell lines, determined that the majority moderately or highly express CXCR4. The minimal non-toxic dose of Aur that inhibits 50-70% of thioredoxin reductase activity was 4 mg/kg (intraperitoneal once a day) in DMS273 (small cell lung cancer) xenografts 212Pb-Pent given IV (1 and 3 µCu/g) was effective at increasing the survival of mice with DMS273 xenografts. Mice were then treated with 1.5, 3 or 6 µCu/g 212Pb-Pent w/wo Aur 4 mg/kg/day. A trend test showed that both increasing dose of 212Pb-Pent and the addition of Aur, caused a significant (p&amp;lt;0.01) delay in tumor growth. There were no significant changes in body weights, complete blood counts, and serum alanine aminotransferase indicating the combination treatments were well tolerated. Radiation dosimetry estimates using quantitative SPECT/CT imaging with Pb203-Pent demonstrated average absorbed doses of 0.133 Gy/µCi (liver), 0.098 Gy/µCi (kidneys), 0.013 Gy/µCi (H292 xenografts), 0.028 Gy/µCi (DMS53 xenografts), 0.057 Gy/µCi (DMS273 xenografts), and 0.096 Gy/µCi (H69AR xenografts). Xenograft absorbed dose levels were positively correlated with CXCR4 expression. Conclusion: The use of 212Pb-Pent therapy to target CXCR4 on NECs showed pre-clinical efficacy in a dose dependent manner that was enhanced by Aur without significant normal tissue toxicity supporting the hypothesis that CXCR4 can be successfully targeted with the radionuclide theragnostic pair, Pb212/Pb203-pentixather. Citation Format: Melissa A. Fath, Dijie Liu, Claudia Robles-Planells, Jordan T. Ewald, Keegan A. Christensen, Spenser S. Johnson, Stephen A. Graves, Douglas R. Spitz, Yusuf Menda, M. Sue O’Dorisio. Targeting CXCR4 and thioredoxin reductase in high grade neuroendocrine tumors and neuroendocrine carcinomas. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5034.

Abstract 3734: Neuroendocrine differentiation (ND) in sensitivity of neuroendocrine tumor (NET) cells to ONC201/TIC10 cancer therapeutic

Abstract Neuroendocrine tumors (NETs) harbor neuroendocrine differentiation (ND) with specific markers including protein gene product 9.5 (PGP9.5) and Chromogranin A (CgA). In prostate cancers (PC), ND is induced by BRN2/SOX2 transcription factors. NET-like cells with low or absent androgen receptor (AR) signaling cause hormone therapy resistance and poor prognosis in PC. Small cell lung carcinoma (SCLC), a high-grade NET, presents with metastasis early and has poor survival. ONC201/TIC10 is a small molecule inducer of TRAIL signaling in clinical trials. ONC201 antagonizes dopamine D2 or D3 receptors (DRD2/DRD3) and is an agonist of mitochondrial caseinolytic protease P (ClpP) resulting in activation of DR5/TRAIL-dependent apoptosis involving the integrated stress response (ISR). ONC201 is active in various malignancies including H3K27M-mutated glioma and NETs expressing high levels of DRD2. We hypothesized that altered BRN2/SOX2 may impact NET apoptosis by ONC201 through the ISR and TRAIL/DR5. We analyzed the expression of neuroendocrine markers PGP9.5, CgA, SOX2, and BRN2, as well as markers of TRAIL signaling pathway markers ATF4, DR5, ClpP, ClpX, and DRD2/DRD3 in PC and SCLC cell lines (N=6) ± treatment with ONC201. Specifically, we compared pre-treatment protein expression levels with the IC50. Our results reveal that DU145 (IC50=3.11μM), PC3 (IC50=3.02μM), and LNCaP (IC50=1.33μM) are ONC201 sensitive. H1417 SCLC expresses CgA, unlike PC3 and DU145. PGP9.5 is expressed in these lines. PGP9.5 is expressed in PC3, DU145, H1417, and H1048 but not in LNCaP and 22RV1. BRN2 is expressed in PC3, H1417, and H1048 but not DU145, LNCaP, or 22RV1. ClpX is expressed in all 6 lines but at lower levels in SCLC. ClpP is expressed in the 6 lines. DR5 is expressed at higher levels in PC3, DU145, LNCaP, and 22RV1 PC versus H1417 and H1048 SCLC. SOX2 is expressed at high levels in H1417 cells. These results are establishing the landscape of ND in PC and SCLC lines for further experimentation and testing of our hypothesis. To characterize the association of BRN2 dysregulation with ONC201 sensitivity, we are performing BRN2/SOX2 knockdown experiments using siRNA and evaluating effects towards ONC201 sensitivity. Our results provide insights into molecular mechanisms of ND in PC and SCLC sensitivity to ONC201. We are also currently working to overexpress BRN2 and SOX2 in cell lines to analyze the impact on neuroendocrine differentiation and ONC201 sensitivity. Citation Format: Elizabeth C. Ding, Wafik S. El-Deiry. Neuroendocrine differentiation (ND) in sensitivity of neuroendocrine tumor (NET) cells to ONC201/TIC10 cancer therapeutic. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3734.

Impact of KRAS and BRAF mutations on treatment efficacy and survival in high-grade gastroenteropancreatic neuroendocrine neoplasms.

High-grade gastroenteropancreatic neuroendocrine neoplasms (HG GEP-NEN) typically disseminate early. Treatment of metastatic disease has limited benefit and prognosis is generally discouraging. Data on the clinical impact of mutations in HG GEP-NEN are scarce. There is an unmet need for reliable biomarkers to predict treatment outcome and prognosis in metastatic HG GEP-NEN. Patients with metastatic HG GEP-NEN diagnosed at three centres were selected for KRAS-, BRAF mutation and microsatellite instability (MSI) analyses. Results were linked to treatment outcome and overall survival. After pathological re-evaluation, 83 patients met inclusion criteria: 77 (93%) GEP neuroendocrine carcinomas (NEC) and six (7%) GEP neuroendocrine tumours (NET) G3. NEC harboured higher frequency of mutations than NET G3. Colon NEC harboured a particular high frequency of BRAF mutations (63%). Immediate disease progression on first-line chemotherapy was significantly higher for NEC with BRAF mutation (73%) versus wild-type (27%) (p = .016) and for colonic primary (65%) versus other NEC (28%) (p = .011). Colon NEC had a significant shorter PFS compared to other primary sites, a finding independent of BRAF status. Immediate disease progression was particularly frequent for BRAF mutated colon NEC (OR 10.2, p = .007). Surprisingly, BRAF mutation did not influence overall survival. KRAS mutation was associated with inferior overall survival for the whole NEC population (HR 2.02, p = .015), but not for those given first-line chemotherapy. All long-term survivors (>24 m) were double wild-type. Three NEC cases (4.8%) were MSI. Colon NEC with BRAF mutation predicted immediate disease progression on first-line chemotherapy, but did not affect PFS or OS. Benefit of first-line platinum/etoposide treatment seems limited for colon NEC, especially for BRAF mutated cases. KRAS mutations did not influence treatment efficacy nor survival for patients receiving first-line chemotherapy. Both frequency and clinical impact of KRAS/BRAF mutations in digestive NEC differ from prior results on digestive adenocarcinoma.

Perspective of molecular imaging and peptide receptor radionuclide therapy in pancreatic neuroendocrine tumors: where do we stand?

The clinical use of nuclear medicine imaging and therapy in pancreatic neuroendocrine tumors has been greatly strengthened since the approval of 68Ga-DOTATATE and 177Lu-DOTATATE. However, many aspects are still under discussion. In this 2-part article, we aim to collect and discuss current evidence of molecular imaging and peptide receptor radionuclide therapy (PRRT) in pancreatic neuroendocrine tumor. In the first part, we will address some critical aspects of 68Ga-SSAs imaging, including diagnostic efficacy, recurrence detection and follow-up, patient selection for PRRT, and pitfalls in image interpretation. Besides, we will also briefly discuss the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography, special imaging strategy in regard to insulinoma, and the status of radiolabeled somatostatin receptor antagonist. In the second part, we aim to review the current evidence of PRRT in pancreatic neuroendocrine tumor, focusing on efficacy and safety in particular. We will also introduce the recent development of PRRT, including PRRT in high-grade neuroendocrine neoplasms, retreatment PRRT, upfront PRRT, PRRT in the setting of neoadjuvant therapy and conversion therapy, combination therapies with PRRT, PRRT with αradionuclides, and PRRT with antagonists.

High-Grade Pancreatic Neuroendocrine Neoplasms: Interobserver Diagnostic Accuracy and Relationship with Clinicopathological and Molecular Characteristics

High-Grade Pancreatic Neuroendocrine Neoplasms: Interobserver Diagnostic Accuracy and Relationship with Clinicopathological and Molecular Characteristics

Diagnostic role and prognostic value of tumor markers in high-grade gastro-enteropancreatic neuroendocrine neoplasms

ObjectivesHigh-grade gastro-enteropancreatic neuroendocrine neoplasms (GEP-NENs) are a heterogeneous group of rare tumors of two different types: well differentiated neuroendocrine tumors grade 3 (NETs G3) and poorly differentiated neuroendocrine carcinomas (NECs). This study aimed to explore the value of eight common preoperative markers in differentiating NETs G3 from NECs and the prognosis prediction of high-grade GEP-NENs. MethodsSeventy-two patients diagnosed with high-grade GEP-NENs who underwent surgery at our institution were recruited for this study. Demographic and clinicopathological characteristics, preoperative serum tumor markers, and survival data were collected and analyzed. Kaplan–Meier methods were used to analyze survival rates, and a Cox regression model was used to perform multivariate analyses. ResultsSerum carcinoembryonic antigen (CEA) was dramatically higher in NECs than in NETs G3 (P = 0.025). After follow-up, 57 of the 72 patients remained for survival analysis. Elevated serum carbohydrate antigen 19-9 (CA19-9), CEA, cancer antigen 125 and sialic acid (SA) levels indicated poorer survival of high-grade GEP-NEN patients. Only CA19-9 (HR: 6.901, 95% CI: 1.843 to 25.837, P = 0.004) was regarded as an independent risk factor for overall survival. Serum CA19-9 (HR: 4.689, 95% CI: 1.127 to 19.506, P = 0.034) was also regarded as an independent factor for overall survival in NECs. ConclusionsSerum CEA levels can be used to distinguish NETs G3 from NECs. Preoperative CA19-9, CEA, cancer antigen 125 and SA levels have predictive value in the prognosis of high-grade GEP-NENs. Preoperative CA19-9, neuron-specific enolase, and SA levels can predict the prognosis of NECs.

Updates of Prostate Cancer from the 2022 World Health Organization Classification of the Urinary and Male Genital Tumors.

Prostate cancer is a heterogeneous disease with a wide spectrum of pathological, clinical, and molecular features. The diagnosis and classification of prostate cancer have been constantly modified with the incorporation of new data. The 5th edition of the World Health Organization (WHO) Classification of Urinary and Genital Tumors was recently published six years after the 4th edition. In this new edition, the classification of prostate cancer has been refined in the diagnostic criteria, grading, nomenclature, and genomics. This paper reviews significant updates to the new WHO classification of prostate cancer, including high-grade prostatic intraepithelial neoplasia, acinar adenocarcinoma, intraductal carcinoma, ductal carcinoma, and neuroendocrine tumors. Controversial issues in the Gleason grading are discussed, such as intraductal carcinoma and tertiary grade. We also highlight distinct genetic and epigenetic alterations in prostate cancer that may contribute to its diverse clinicopathologic features. Overall, the 5th edition of the WHO classification provides a comprehensive assessment of prostate cancer with morphologic, immunohistochemical, genomic, and clinical data, which may represent an optimal paradigm for diagnosing and treating prostate cancer.

Integrated Genomic and Clinicopathologic Approach Distinguishes Pancreatic Grade 3 Neuroendocrine Tumor From Neuroendocrine Carcinoma and Identifies a Subset With Molecular Overlap

Distinguishing grade 3 pancreatic neuroendocrine tumor (G3 PanNET) from neuroendocrine carcinoma (PanNEC) is a known diagnostic challenge, and accurate classification is critical because clinical behavior and therapies differ. Although current recommendations suggest that immunohistochemistry for p53, Rb, ATRX, and DAXX can distinguish most cases, some cases remain difficult to classify using this approach. In this study, we reviewed 47 high-grade neoplasms originally diagnosed as pancreatic neuroendocrine neoplasms. In addition to the currently recommended stains, we performed capture-based sequencing of approximately 500 cancer genes and immunohistochemistry for p16 and trypsin or chymotrypsin. Using an integrated molecular and clinicopathologic approach, 42 (89%) of 47 cases had a clear final diagnosis of either G3 PanNET (n = 17), PanNEC (n = 17), or mixed acinar-NEC (n = 8). The 17 G3 PanNETs demonstrated frequent alterations in MEN1 (71%), DAXX (47%), ATRX (24%), TSC2 (35%), SETD2 (42%), and CDKN2A (41%). Contrary to prior reports, TP53 alterations were also common in G3 PanNETs (35%) but were always mutually exclusive with CDKN2A alterations in this group. The 17 PanNECs demonstrated frequent alterations in TP53 (88%), cell cycle genes RB1 (47%), CCNE1/CCND1 (12%), CDKN2A (29%), and in KRAS (53%) and SMAD4 (41%); TP53 was coaltered with a cell cycle gene in 76% of PanNECs. Diffuse strong p16 staining was observed in 69% of PanNECs in contrast to 0% of G3 PanNETs. The 8 acinar-NECs had recurrent alterations in ATM (25%), APC (25%), and STK11 (25%). Five cases remained difficult to classify, 3 of which exhibited overlapping molecular features with alterations in MEN1 with or without ATRX, and RB1 with or without TP53, making it unclear whether to classify as PanNET or PanNEC. Our data demonstrate that molecular profiling and immunohistochemistry for p16 greatly improve the diagnostic accuracy of high-grade pancreatic neuroendocrine neoplasms and identify a subset of rare cases with overlapping features of both PanNET and PanNEC.

Digital Image Analysis of Ki67 Heterogeneity Improves the Diagnosis and Prognosis of Gastroenteropancreatic Neuroendocrine Neoplasms

Ki67 is a reliable grading and prognostic biomarker of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). The intratumor heterogeneity of Ki67, correlated with tumor progression, is a valuable factor that requires image analysis. The application of digital image analysis (DIA) enables new approaches for the assessment of Ki67 heterogeneity distribution. We investigated the diagnostic utility of Ki67 heterogeneity parameters in the classification and grading of GEP-NENs and explored their clinical values with regard to their prognostic relevance. The DIA algorithm was performed on whole-slide images of 102 resection samples with Ki67 staining. Good agreement was observed between the manual and DIA methods in the hotspot evaluation (R2 = 0.94, P < .01). Using the grid-based region of interest approach, score-based heat maps provided a distinctive overview of the intratumoral distribution of Ki67 between neuroendocrine carcinomas and neuroendocrine tumors. The computation of heterogeneity parameters related to DIA-determined Ki67 showed that the coefficient of variation and Morisita-Horn index were directly related to the classification and grading of GEP-NENs and provided insights into distinguishing high-grade neuroendocrine neoplasms (grade 3 neuroendocrine tumor vs neuroendocrine carcinoma, P < .01). Our study showed that a high Morisita-Horn index correlated with poor disease-free survival (multivariate analysis: hazard ratio, 56.69), which was found to be the only independent predictor of disease-free survival in patients with GEP-NEN. These spatial biomarkers have an impact on the classification and grading of tumors and highlight the prognostic associations of tumor heterogeneity. Digitization of Ki67 variations provides a direct and objective measurement of tumor heterogeneity and better predicts the biological behavior of GEP-NENs.

Next-generation sequencing proves clonal relationship between two distinguished lung and liver carcinomas by standard histopathology approach

Introduction: Two tumors having different histopathologies at anatomically distinct sites giving the picture of dual primary malignancies. Here we presented a case of two possible primary tumors and one secondary mass. Case Report: A 74-year-old female, active smoker, without personal or family cancer history presented with early satiety and weakness for two months. Systems review was positive for a “raw” feeling in stomach, alleviated with antacids. Vital signs were stable with a negative abdominal exam. Lab showed leukocytosis 24.8 K/uL (3.5–10.8 K/uL) with left shift, microcytic anemia with hemoglobin 6.1 g/dL (12.0–16.0 g/dL), and reactive thrombocytosis 477 K/uL (130–400 K/uL). Contrast-enhanced computed tomography (CT) showed right upper lobe necrotizing cavitating lesion with reactive mediastinal and right hilar lymphadenopathy, two irregular hypodense lesions in pancreatic head and tail without ductal dilation with two irregular hypodense liver lesions. Immunohistochemistry of lung and pancreatic lesions were biopsied through endoscopic ultrasound (EUS), consistent with poorly differentiated squamous cell carcinoma (SCC) with extensive necrosis, which indicates pancreatic masses are likely metastases from the lung. Liver lesion biopsy exhibited high-grade neuroendocrine tumor (NET) with focal necrosis. Next gene sequencing was pursued. Given poor functional status, palliative immunotherapy was offered; however, the patient succumbed to respiratory failure. Conclusion: Given the morphology and immunoprofile, differential diagnosis includes dual primary cancers with one metastasis, or primary SCC with metastasis with neuroendocrine differentiation. Despite having different histopathology and immunophenotype, both lung and liver tumors harbor the same molecular profile even at the variants of unknown significance that show identical mutations. As a result, they are directly related. TP53, RB1, MYCL1, and MEK1 mutations are more prevalent in SCC than NET. Tumor mutation burden values may vary as the tumor clonal structure varies between primary and metastatic sites, with higher rates of monoclonal structure recorded in metastases due to clonal selection, leading to a reduction in overall genetic diversity (“bottlenecking”). This raises the suspicion that the liver tumor is a SCC with neuroendocrine differentiation. The paucity of the specimen and rapid clinical course limited further investigation. Germline testing would have been useful to determine whether these findings are somatic or germline.

Exploratory genomic analysis of high-grade neuroendocrine neoplasms across diverse primary sites.

High-grade (grade 3) neuroendocrine neoplasms (G3 NENs) have poor survival outcomes. From a clinical standpoint, G3 NENs are usually grouped regardless of primary site and treated similarly. Little is known regarding the underlying genomics of these rare tumors, especially when compared across different primary sites. We performed whole transcriptome (n = 46), whole exome (n = 40), and gene copy number (n = 43) sequencing on G3 NEN formalin-fixed, paraffin-embedded samples from diverse organs (in total, 17 were lung, 16 were gastroenteropancreatic, and 13 other). G3 NENs despite arising from diverse primary sites did not have gene expression profiles that were easily segregated by organ of origin. Across all G3 NENs, TP53, APC, RB1, and CDKN2A were significantly mutated. The CDK4/6 cell cycling pathway was mutated in 95% of cases, with upregulation of oncogenes within this pathway. G3 NENs had high tumor mutation burden (mean 7.09 mutations/MB), with 20% having >10 mutations/MB. Two somatic copy number alterations were significantly associated with worse prognosis across tissue types: focal deletion 22q13.31 (HR, 7.82; P = 0.034) and arm amplification 19q (HR, 4.82; P = 0.032). This study is among the most diverse genomic study of high-grade neuroendocrine neoplasms. We uncovered genomic features previously unrecognized for this rapidly fatal and rare cancer type that could have potential prognostic and therapeutic implications.

Optimal Combination of Neuroendocrine Markers for the Detection of High-Grade Neuroendocrine Tumors of the Sinonasal Tract and Lung.

Identification of neuroendocrine (NE) differentiation is critical to the classification of head and neck (HN) and lung tumors. In combination with tumor morphology, immunohistochemical (IHC) documentation of NE differentiation is necessary for the diagnosis of NE tumors. The purpose of this study is to determine the sensitivity and concordance of two novel NE markers (mASH1, INSM1) across a group of high-grade NE tumors of the sinonasal tract and lung, and to compare their expression with the current widespread use of conventional NE markers, synaptophysin (SYN) and chromogranin A (CGA). In addition, expression of PARP1 is examined as a potential novel therapeutic target. Thirty-nine high-grade NE tumors, 23 of the HN and 16 of the lung, were reevaluated by two subspecialized HN and thoracic pathologists, and subsequently stained with mASH1, INSM1, and PARP1. Sensitivity and degree of concordance of all possible combinations of markers were assessed. Sensitivities (standard error) were as follows: mASH1 41% (0.08), INSM1 44% (0.08), SYN 56% (0.08), and CGA 42% (0.09); combination of all four NE markers: 73% (0.08). Sensitivity and standard error for PARP1 was 90% and 0.05, respectively. Highest sensitivity to detect NE differentiation in high-grade NE tumors of the HN and thoracic region was achieved with a combination of four NE markers. Moderate concordance was found with combinations of mASH1 and INSM1 and traditional NE markers, respectively. Consistent overexpression of PARP1 in high-grade tumors with NE differentiation in the HN and lung opens eligibility for PARP1 inhibitor trials.

LBODP064 A Rare Case Of Paraneoplastic Cushing Syndrome Associated With Pulmonary Carcinoid Tumor

Abstract A 67-year-old female with a history of primary pulmonary carcinoid tumor with metastasis to the liver presented with shortness of breath and generalized weakness. On presentation, her vital signs were BP 170/100 mm Hg, pulse 99/min, RR 18/min, O2 saturation 85% on room air. Physical exam was significant for diffuse rhonchi in bilateral lungs. Initial labs showed marked hypokalemia with K+ 2.5 and HCO3- 42. CT scans showed increased numbers of nodules and sizes in the lungs and numerous large liver masses. The adrenal glands and aldosterone-to-renin ratio were within normal limits. A random cortisol level was 113.14 ug/dL (2.50-12.50) with a concomitant elevated ACTH level of 353.6 pg/mL (7.2-63.3), while brain MRI was negative for pituitary or metastatic lesion. A liver mass biopsy revealed a transformation into a high-grade neuroendocrine tumor with a Ki-67 of 32%. A low dose dexamethasone suppression test showed a cortisol level of 66. 08. Interpreting this result and the imaging studies, it was determined that hypercortisolism was secondary to ectopic ACTH production. This clinical presentation and findings supported her cancer transformation to a functional metastatic neuroendocrine cancer with a paraneoplastic syndrome previously unknown. She was started on spironolactone as a potassium-sparing diuretic, itraconazole to inhibit cortisol synthesis based on inpatient formulary at that time, and combination chemotherapy with cisplatin and etoposide. Over the next few weeks, she developed signs of Cushing syndrome with leg swelling, facial puffiness, proximal muscle weakness, muscle loss, easy bruising, abdominal striae, coccydynia, glucose intolerance, and acid reflux. She had complications of peptic ulcer disease with bleeding, Clostridium difficile colitis, bacterial pneumonia, persistent hypokalemia, hypomagnesemia, and chemotherapy-induced anemia and severe thrombocytopenia. A repeat cortisol level was &amp;gt;150. 00 ug/dL despite the uptritation of itraconazole, suggesting not so much success. With insurance approval, she was started on ketoconazole, on which the cortisol levels on Days 5, 12, and 19 were 114.74 ug/dL, 126.84 ug/dL, and 118.42 ug/dL, respectively. Given uncontrolled hypercortisolism, a novel cortisol synthesis inhibitor, osilodrostat, was ordered and approved. However, two days later, the patient required another hospitalization for respiratory failure and severe sepsis from Coronavirus Disease 2019 pneumonia and Acinetobacter radioresistens bacteremia, and she passed away. This case highlights the therapeutic challenge of managing a late presentation of Cushing syndrome from ectopic ACTH production secondary to the progression of metastatic lung cancer. As such, clinicians should periodically consider screening for the subclinical-Cushing syndrome to diagnose such cases early, preventing such consequences of overt Cushing syndrome. Presentation: No date and time listed

Capecitabine and temozolomide for metastatic intermediate to high-grade pancreatic neuroendocrine neoplasm: a single center experience

The combination of capecitabine and temozolomide (CAPTEM) is one of the treatment options for metastatic pancreatic neuroendocrine neoplasms (pNENs). This study aims to evaluate the efficacy of CAPTEM in patients with metastatic intermediate to high-grade pancreatic neuroendocrine tumor (pNET) or carcinoma (pNEC). This study was conducted retrospectively in a single center. Patients were treated for intermediate to high-grade tumor with 750 mg/m² of capecitabine twice daily from day 1 to 14 and 200 mg/m² of temozolomide once daily from day 10 to 14, repeating twice in a cycle of 28 days. The primary outcomes were durations of overall survival (OS) and progression-free survival (PFS). The secondary outcomes consisted of objective response rate and disease control rate. A total of 12 patients (grade 2 NET in six, grade 3 NET in three, NEC in three patients) who received CAPTEM were included in this study. Patients received a median of five cycles (range, 2 to 46) of CAPTEM. The median dose combined 1,150 mg of capecitabine and 300 mg of temozolomide. The median OS and PFS were 41.2 months (range, 3.2 to 167) and 39.7 months (range, 2.1 to 100), respectively. Patients with NET had longer OS and PFS compared to those of patients with NEC (p = 0.002 and p = 0.028). High Ki-67 proliferative index (&gt; 50%) was significantly associated with poor survival outcomes. CAPTEM showed favorable survival outcomes in patients with metastatic intermediate to high-grade pNENs. Our study supports that CAPTEM may be an effective treatment option for metastatic pNENs.

ODP315 Hypoglycemia: Neuroendocrine Tumor of the Pancreas with Liver Metastasis and Transformation to Insulinoma

Abstract Background Neuroendocrine tumors (NETs) are rare, can be found in any part of the body including the gastrointestinal tract, lung, and pancreas and have potential for metastasis. Clinical Case A 39-year-old male with stage IV high grade neuroendocrine tumor of the pancreas with metastasis to the liver and lymph nodes whose disease progressed despite treatment with systemic therapy who presented with severe hypoglycemia. Diagnosis and management of his hypoglycemia was difficult. For the diagnosis, patient's serum blood glucose did not always correlate with his capillary blood glucose via finger sticks, which lead to a delay in his diagnosis. Also, his diagnosis was not straight forward as he did not respond adequately to the glucagon following a serum glucose of less than 55 mg/dL (normal 70-110 mg/dL) during a diagnostic fast. Once critical labs were obtained, it took days for the results. In the interim, his hypoglycemia was managed with dextrose infusions at 10%, 20% and as high as 50%, frequent meals, and high dose steroids, yet he still had daily symptomatic hypoglycemia. A diagnosis of insulinoma was made with the following critical lab results: insulin 70.4 uIU/mL (2.6-24.9), C-peptide 12.6 ng/mL (1.1-4.4), proinsulin 407.6 pmol/L (0. 0-10. 0), beta-hydroxybutyrate &amp;lt;0. 050 mmol/L (0. 02-0.27), insulin antibodies &amp;lt;5. 0 uU/mL, negative sulfonylurea screen, insulin-growth factor-1 (IGF-1) 77 ng/mL (90-278), and insulin-growth factor binding protein three (IGF-BP3) 2133 ug/L (2571-5982). Patient was treated with both diazoxide and hepatic artery embolization to reduce tumor burden. His dose of diazoxide was titrated to maintain normoglycemia. He had mild tumor lysis syndrome that did not require dialysis. His hypoglycemia resolved within a few days of treatment and was discharged from the hospital with a continuous glucose monitor (CGM), diazoxide and hydrocortisone. It is our belief that transformation of the liver lesions to insulinoma was the cause of his hypoglycemia. Conclusion We recommend that patients with metastases from their neuroendocrine tumor who develop hypoglycemia be evaluated for insulinoma and if found should be treated with diazoxide and if not surgical candidates to consider hepatic artery embolization. Presentation: No date and time listed