Markers Of Neuroendocrine Differentiation Research Articles

Abstract 4630: Clinical and epidemiological profile of neuroendocrine differentiation- A hospital-based retrospective study

Abstract Background: Neuroendocrine differentiation (NED) in carcinomas is poorly studied globally, despite its distinct clinical features, disease progression, pathology, treatment outcomes, and poor prognosis. Therefore, it is imperative to conduct further analysis utilizing extensive clinical samples to unveil the clinical and epidemiological profile of NED. Methods: A retrospective study was conducted to analyze the histopathological samples of patients diagnosed with malignant tumor using immunohistochemical techniques for NED markers, such as ChrA, Syno and CD56. The morbidity and prognosis of NED patient would be analyzed subsequently. Eligible patients must have pathologically confirmed gastric cancer, colorectal cancer, lung cancer, esophageal cancer and prostate cancer with no prior neoadjuvant chemotherapy or radiotherapy received before surgery. Patients aged 18-75 years with normal organ functions were enrolled. Results: Between January 2017 and June 2018, over 450 cases were enrolled. Preliminary analysis focused on 36 esophageal cancer (EC) and 44 prostatic cancer (PC) samples. NED markers were expressed in 4 (11.1%) of 36 EC patients, including 4 cases positive for Syno, 1 case positive for ChrA, and 2 cases positive for CD56. Meanwhile, NED markers were expressed in 15 (34.1%) of 44 PC patients, including 10 cases positive for Syno, 15 cases positive for ChrA, and 2 cases positive for CD56. Conclusion: Neuroendocrine differentiation is obviously observed in EC and PC. The encouraging prevalence rate of NED may have clinical implications for individualized treatment. Further research is needed to explore this area in more detail. Citation Format: Yaru Wen, Susheng Shi. Clinical and epidemiological profile of neuroendocrine differentiation- A hospital-based retrospective study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4630.

Abstract 3036: Sensitivity of ONC201/TIC10 cancer therapeutic on neuroendocrine prostate cancer (NEPC) and neuroendocrine differentiation (NED)

Abstract Although androgen deprivation therapy and androgen receptor (AR) blockade are highly effective therapies for metastatic prostate cancer (PCa), most patients develop resistance, leading to castration-resistant prostate cancer (CRPC). A subset of CRPC shows neuroendocrine prostate cancer (NEPC) features, which are associated with poor prognosis and limited therapeutic strategies. NEPC is characterized by oncogenic driver activation and epigenetic changes, partly controlled by transcription factors like BRN2 and SOX2. AR has been shown to suppress BRN2 transcription, which is required for NEPC, and BRN2-dependent regulation of the NEPC marker SOX2 (Bishop et al., 2017). Dordaviprone (ONC201/TIC10) is a first-in-class small molecule that antagonizes DRD2, induces tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), and activates the integrated stress response (ISR). Neuroendocrine tumors express significant DRD2 levels, suggesting ONC201 as a potential therapeutic strategy in NEPC or when drivers for disease progression are overexpressed (OE). PCa cell lines PC3, DU145, LNCaP, and 22RV1 are ONC201 sensitive, with IC50=2.87 μM, 3.18 μM, 1.31 μM, and 1.16 μM, respectively (Ding et al., 2023). To characterize the association of BRN2/SOX2 dysregulation with ONC201 sensitivity, we transiently OE BRN2/SOX2 in PCa. We hypothesized that markers of neuroendocrine differentiation (NED), activation of the ISR, TRAIL, and ClpP and dopamine receptor expression contribute to NEPC cell death and sensitivity to ONC201. We performed CellTiter-Glo experiments to assess viability after 96 hours ± BRN2 OE. DU145 cells with BRN2 OE increased their sensitivity to ONC201 (IC50=2.75 µM) compared to empty vector (IC50=3.03 µM). Colony formation assays were conducted in PCa and analyzed 7 days after ONC201 treatment to show ONC201 effect on PCa cell lines. DU145 was treated at 0.5, 1, and 2 µM of ONC201. There were 95 ± 3.22 colonies for the control group, 83 ± 5.22 colonies with 0.5 µM, 74 ± 3.64 colonies with 1 µM, and 8 ± 2.03 colonies with 2 µM ONC201. DU145 showed a significant reduction in colony-forming ability when treated with 1 and 2 uM ONC201 compared to the control, with P values of <0.05 and <0.0001, respectively. We OE BRN2 and observed changes in NED markers and ISR pathway. In PC3, FoxO1 and ATF4 levels increased. In DU145, FoxO1, ENO2, PGP9.5, CgA, and ATF4 levels decreased. We reveal that DU145 OE at 48 hours does not result in greater expression of NEPC markers. BRN2 OE significantly increased PCa cell sensitivity to ONC201 and was evident without an increase in common phenotypical markers used for NEPC assessment (FoxO1, ENO2, PGP9.5, CgA). Expression change was not shown when PCa had an integral AR pathway. Ongoing efforts are observing ONC201 treatment effects on NED markers and the TRAIL pathway due to BRN2 OE and showing increased sensitivity of PCa to ONC201 with BRN2 OE. Citation Format: Elizabeth C. Ding, Maximilian Pinho-Schwermann, Shengliang Zhang, Connor Purcell, Wafik S. El-Deiry. Sensitivity of ONC201/TIC10 cancer therapeutic on neuroendocrine prostate cancer (NEPC) and neuroendocrine differentiation (NED) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3036.

Abstract 5067: Exploring the genomic landscape of de novo neuroendocrine prostate cancer: Insights for innovative therapies from spatial gene expression analysis

Abstract Introduction & Objectives Neuroendocrine prostate cancer (NEPC) accounts for less than 1% of all prostate cancers but has a worse prognosis than androgen receptor-positive prostate adenocarcinoma (ARPC). Rare cases exist where both de novo NEPC and ARPC are found in the same tissue sample. Our study examines one such unique case: a 78-year-old male treated at Ehime University Hospital who was diagnosed with both ARPC and adjacent de novo metastatic NEPC. This case provides an excellent opportunity for studying gene expression in these two types of prostate cancer. Materials & Methods We used Visium CytAssist Spatial Gene Expression technology from 10x Genomics to analyze formalin-fixed, paraffin-embedded (FFPE) tissue samples from this unique patient. Results We observed elevated expression levels of specific neuroendocrine markers like PEG10, DLL3, NCAM1, SYP, and CHGA in de novo NEPC regions. In contrast, androgen receptor markers such as KLK3, ACPP, TMPRSS2, and NKX3.1 were more prevalent in ARPC areas. Furthermore, genes like Chek1, BRCA1/2, TOP2A, and FANCA were also elevated in NEPC, suggesting that PARP and TOP2 inhibitors could be effective. Expression levels of Rbfox3 and SFRTM2 were lower in NEPC areas, implying possible roles in epithelial-mesenchymal transition (EMT) and Wnt signaling pathways. Additionally, fibrotic markers like HGF, HMOX1, ELN, and GREM1 were upregulated, suggesting that de novo NEPC tumors might be 'immune cold,' thus requiring treatments to boost the effectiveness of immune checkpoint inhibitors. Conclusion The data from additional cases could open the door for new treatment options for NEPC and improve survival rates for castration-resistant prostate cancer patients. Our research serves as a pioneering application of Visium CytAssist on FFPE samples and is the first to examine gene expression in both ARPC and de novo NEPC. A subset of these findings was published in the International Journal of Molecular Science (IJMS) in May 2023. Citation Format: Ryuta Watanabe, Noriyoshi Miura, Mie Kurata, Riko Kitazawa, Tadahiko Kikugawa, Takashi Saika. Exploring the genomic landscape of de novo neuroendocrine prostate cancer: Insights for innovative therapies from spatial gene expression analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5067.

Immunosuppressive role of BDNF in therapy-induced neuroendocrine prostate cancer.

Prostate stromal cells play a crucial role in the promotion of tumor growth and immune evasion in the tumor microenvironment (TME) through intricate molecular alterations in their interaction with prostate cancer (PCa) cells. While the impact of these cells on establishing an immunosuppressive response and influencing PCa aggressiveness remains incompletely understood. Our study shows that the activation of the leukemia inhibitory factor (LIF)/LIF receptor (LIFR) pathway in both prostate tumor and stromal cells, following androgen deprivation therapy (ADT), leads to the development of an immunosuppressive TME. Activation of LIF/LIFR signaling in PCa cells induces neuroendocrine differentiation (NED) and upregulates immune checkpoint expression. Inhibition of LIF/LIFR attenuates these effects, underscoring the crucial role of LIF/LIFR in linking NED to immunosuppression. Prostate stromal cells expressing LIFR contribute to NED and immunosuppressive marker abundance in PCa cells, while LIFR knockdown in prostate stromal cells reverses these effects. ADT-driven LIF/LIFR signaling induces brain-derived neurotrophic factor (BDNF) expression, which, in turn, promotes NED, aggressiveness, and immune evasion in PCa cells. Clinical analyses demonstrate elevated BDNF levels in metastatic castration-resistant PCa (CRPC) and a positive correlation with programmed death-ligand 1 (PDL1) and immunosuppressive signatures. This study shows that the crosstalk between PCa cells and prostate stromal cells enhances LIF/LIFR signaling, contributing to an immunosuppressive TME and NED in PCa cells through the upregulation of BDNF.

Recurrent Wnt Pathway and ARID1A Alterations in Sinonasal Olfactory Carcinoma

Sinonasal tumors with neuroepithelial differentiation, defined by neuroectodermal elements reminiscent of olfactory neuroblastoma (ONB) and epithelial features such as keratin expression or gland formation, are a diagnostically challenging group that has never been formally included in sinonasal tumor classifications. Recently, we documented that most of these neuroepithelial neoplasms have distinctive histologic and immunohistochemical findings and proposed the term “olfactory carcinoma” to describe these tumors. However, the molecular characteristics of olfactory carcinoma have not yet been evaluated. In this study, we performed targeted molecular profiling of 23 sinonasal olfactory carcinomas to further clarify their pathogenesis and classification. All tumors included in this study were composed of high-grade neuroectodermal cells that were positive for pankeratin and at least 1 specific neuroendocrine marker. A significant subset of cases also displayed rosettes and neurofibrillary matrix, intermixed glands with variable cilia, peripheral p63/p40 expression, and S100 protein-positive sustentacular cells. Recurrent oncogenic molecular alterations were identified in 20 tumors, including Wnt pathway alterations affecting CTNNB1 (n = 8) and PPP2R1A (n = 2), ARID1A inactivation (n = 5), RUNX1 mutations (n = 3), and IDH2 hotspot mutations (n = 2). Overall, these findings do demonstrate the presence of recurrent molecular alterations in olfactory carcinoma, although this group of tumors does not appear to be defined by any single mutation. Minimal overlap with alterations previously reported in ONB also adds to histologic and immunohistochemical separation between ONB and olfactory carcinoma. Conversely, these molecular findings enhance the overlap between olfactory carcinoma and sinonasal neuroendocrine carcinomas. A small subset of neuroepithelial tumors might better fit into the superseding molecular category of IDH2-mutant sinonasal carcinoma. At this point, sinonasal neuroendocrine and neuroepithelial tumors may best be regarded as a histologic and molecular spectrum that includes core groups of ONB, olfactory carcinoma, neuroendocrine carcinoma, and IDH2-mutant sinonasal carcinoma.

Comparison of INSM1 immunostaining with established neuroendocrine markers Synaptophysin and Chromogranin A in over 14,000 neuroendocrine and non-neuroendocrine tumors

Abstract Introduction/Objective INSM1 is a transcription factor protein which is increasingly used as an immunohistochemical marker for neuroendocrine differentiation. Methods/Case Report To determine the prevalence of INSM1 expression in tumors and its expression pattern in normal tissues, tissue microarrays containing 14,908 samples from 117 different tumor types/subtypes as well as 76 different normal tissues were analyzed by immunohistochemistry. Results (if a Case Study enter NA) INSM1 was positive in 89.2% of 471 neuroendocrine neoplasms (NEN) and in 3.5% of 11,815 non-neuroendocrine neoplasms that were successfully analyzed. INSM1 positivity occurred in 59 non- neuroendocrine tumor entities, of which 15 entities contained at least one strongly positive case. Comparison with synaptophysin and chromogranin A revealed that in NEN, synaptophysin showed the highest sensitivity (93.3%), followed by INSM1 (89.2%) and chromogranin A (87.5%). In neuroendocrine carcinomas (NEC), sensitivity was highest for INSM1 (88.0%), followed by synaptophysin (86.5%) and chromogranin A (66.4%). The additional use of INSM1 increased the sensitivity for detecting neuroendocrine differentiation in NEN from 88.2% (synaptophysin and chromogranin A) to 91.2% (synaptophysin, chromogranin A and INSM1). Conclusion Our study shows that INSM1 is a useful additional marker for neuroendocrine differentiation that shows a particularly high sensitivity in NEC. The additional use of INSM1 results in a higher sensitivity for the identification of a neuroendocrine differentiation than what can be obtained by using only synaptophysin and chromogranin A.

Comparison of INSM1 immunostaining with established neuroendocrine markers synaptophysin and chromogranin A in over 14,000 neuroendocrine and non-neuroendocrine tumors

INSM1 is a transcription factor protein which is increasingly used as an immunohistochemical marker for neuroendocrine differentiation. To determine the prevalence of INSM1 expression in tumors and its expression pattern in normal tissues, tissue microarrays containing 14,908 samples from 117 different tumor types/subtypes as well as 76 different normal tissues were analyzed by immunohistochemistry. INSM1 was positive in 89.2% of 471 neuroendocrine neoplasms (NEN) and in 3.5% of 11,815 non-neuroendocrine neoplasms that were successfully analyzed. At least an occasional weak INSM1 positivity was observed in 59 different non-neuroendocrine tumor entities, of which 15 entities contained at least one case with strong INSM1 staining. A comparison with synaptophysin and chromogranin A staining revealed that in NEN, synaptophysin showed the highest sensitivity (93.3%), followed by INSM1 (89.2%) and chromogranin A (87.5%). In neuroendocrine carcinomas (NEC), sensitivity was highest for INSM1 (88.0%), followed by synaptophysin (86.5%) and chromogranin A (66.4%). If INSM1 was used as an additional marker, the sensitivity for detecting neuroendocrine differentiation in NEN increased from 96.6% (synaptophysin and chromogranin A) to 97.2% (synaptophysin, chromogranin A and INSM1). Our study shows that INSM1 is a useful additional marker for neuroendocrine differentiation with high sensitivity, particularly in NEC.

2025P Stratified control study of neuroendocrine differentiation and potential clinicopathologic markers

2025P Stratified control study of neuroendocrine differentiation and potential clinicopathologic markers

19P Stratified control study on neuroendocrine differentiation and potential clinical markers in patients with limited-stage small-cell lung cancer

19P Stratified control study on neuroendocrine differentiation and potential clinical markers in patients with limited-stage small-cell lung cancer

Neuroendocrine prostate tumors: histologic features and therapy

Neuroendocrine (NE) tumors of the prostate are rare tumors, that can arise de novo but much more commonly occur after androgen deprivation therapy for prostate adenocarcinoma. NE tumors of the prostate are classified into: adenocarcinoma with NE differentiation, well-differentiated NE tumor/carcinoid, small-cell NE carcinoma, large cell NE carcinoma, adenocarcinoma with Paneth cell NE differentiation and mixed NE carcinoma—acinar adenocarcinoma. IHC plays a vital role and should be approached at two levels. For the issue of confirming NE differentiation, markers for NE differentiation include synaptophysin, chromogranin, and CD56. If there is any uncertainty about the histogenesis, that is, whether a tumor is primary to the prostate, markers for prostatic lineage—PSA, PSAP, PSMA, prostein (p501s), NKX3.1, ERG (by IHC or FISH)—may be used. Actually, platinum-based chemotherapy is commonly administered to patients with pure small cell carcinoma based on small cell lung cancer (SCLC) data and the accumulating data for aggressive variants of castration-resistant prostate cancer (AVPC). This may consist of a combination of carboplatin (or sometimes cisplatin) plus either etoposide (based on SCLC) or a taxane (especially if mixed histology or AVPC features). A combination regimen of cisplatin, etoposide, and doxorubicin has been also investigated but the benefit-risk ratio of the three-drug combination was considered unfavorable. Unfortunately, platinum-based chemotherapy often presents high toxicity and a short overall survival. Results of currently ongoing preclinical and clinical studies are expected to enhance our understanding of these tumors’ underlying biology and guide our efforts toward the development of personalized medicine through targeted diagnostic and therapeutic approaches.

Pathologic exploration of neuroendocrine differentiation in carcinomas.

e16238 Background: Tumor with neuroendocrine differentiation (NED) has been verified in non-neuroendocrine organ adenocarcinomas. However, the incidence of NED in various studies varies greatly due to the different selection and criteria of NED markers. Further analysis of large clinical samples is still needed to reveal its biological characteristics and clarify the diagnosis and treatment of NED. Methods: From January 2017 to June 2018，a total of 450 histopathological samples were collected and analyzed retrospectively from patients with multiple malignant cancers, including gastric cancer (GC), colorectal cancer (CRC), lung cancer, breast cancer and prostate cancer treated in Cancer Hospital, Chinese Academy of Medical Sciences. Immunohistochemical staining for NED markers such as synaptophysin (Syn), chromogranin A (ChrA), and neural cell adhesion molecule (CD56) were performed to explore the incidence of different cancer types. Furthermore, NED or non-NED patients were evaluated comparatively in terms of pathological characteristics and prognosis. Results: Up to February 6, 2023, 129 CRC and GC samples were measured. 9 (15.3%) of 59 CRC patients were positive for NED markers, including 7 cases of Syn (+), 6 cases of ChrA (+) and 2 cases of CD56 (+). Moreover, 4 (6.8%) of 59 patients were positive for at least 2 NED markers in CRC. 18 (52.9%) of 34 gastric signer ring cell carcinoma patients were positive for NED markers, including 15 cases of Syn (+) and 14 cases of ChrA (+). Meanwhile, 10 (27.8%) of 36 gastric tubular adenocarcinoma patients were positive for NED markers, including 6 cases of Syn (+) and 10 cases of ChrA (+). Particularly, 17 (24.3%) (11/6, signer ring cell carcinoma/ tubular adenocarcinoma) of 70 GC patients were positive for at least two NED markers. Conclusions: NED is widely present in colorectal cancer and gastric cancer, especially in gastric signer ring cell carcinoma. The encouraging outcomes of the NED prevalence rate may shed light on the individualized treatments for patients with carcinomas. Further explorations are needed in the following research. [Table: see text]

Rectal carcinoma with dual differentiation toward enteroblastic and neuroendocrine features arising in a patient with ulcerative colitis: a case report

BackgroundColorectal carcinoma with enteroblastic differentiation is a rare subtype of colorectal carcinomas expressing at least one characteristic immunohistochemical marker among α-fetoprotein, glypican-3, and spalt-like transcription factor 4. On the other hand, colorectal carcinoma with neuroendocrine differentiation is also a unique subtype of colorectal carcinomas showing expression of at least one distinctive marker among chromogranin A, synaptophysin, and CD56.Case presentationWe experienced an extremely rare case of rectal carcinoma with dual differentiation toward enteroblastic and neuroendocrine features in a 53-year-old male patient with long-standing ulcerative colitis (UC). Most of the tumor cells were positive for enteroblastic differentiation markers and approximately a half of them for neuroendocrine differentiation markers. Some tumor cells showed only enteroblastic differentiation, and some did only neuroendocrine feature, but some showed both enteroblastic and neuroendocrine differentiation.ConclusionColorectal carcinoma with dual differentiation toward enteroblastic and neuroendocrine features has not been reported yet. Neoplastic transformation from pluripotent stem cells in dysplastic epithelium of long-standing UC patients may be associated with such dual differentiation features.

Pulmonary cancers across different histotypes share hybrid tuft cell/ionocyte-like molecular features and potentially druggable vulnerabilities

Tuft cells are chemosensory epithelial cells in the respiratory tract and several other organs. Recent studies revealed tuft cell-like gene expression signatures in some pulmonary adenocarcinomas, squamous cell carcinomas (SQCC), small cell carcinomas (SCLC), and large cell neuroendocrine carcinomas (LCNEC). Identification of their similarities could inform shared druggable vulnerabilities. Clinicopathological features of tuft cell-like (tcl) subsets in various lung cancer histotypes were studied in two independent tumor cohorts using immunohistochemistry (n = 674 and 70). Findings were confirmed, and additional characteristics were explored using public datasets (RNA seq and immunohistochemical data) (n = 555). Drug susceptibilities of tuft cell-like SCLC cell lines were also investigated. By immunohistochemistry, 10–20% of SCLC and LCNEC, and approximately 2% of SQCC expressed POU2F3, the master regulator of tuft cells. These tuft cell-like tumors exhibited “lineage ambiguity” as they co-expressed NCAM1, a marker for neuroendocrine differentiation, and KRT5, a marker for squamous differentiation. In addition, tuft cell-like tumors co-expressed BCL2 and KIT, and tuft cell-like SCLC and LCNEC, but not SQCC, also highly expressed MYC. Data from public datasets confirmed these features and revealed that tuft cell-like SCLC and LCNEC co-clustered on hierarchical clustering. Furthermore, only tuft cell-like subsets among pulmonary cancers significantly expressed FOXI1, the master regulator of ionocytes, suggesting their bidirectional but immature differentiation status. Clinically, tuft cell-like SCLC and LCNEC had a similar prognosis. Experimentally, tuft cell-like SCLC cell lines were susceptible to PARP and BCL2 co-inhibition, indicating synergistic effects. Taken together, pulmonary tuft cell-like cancers maintain histotype-related clinicopathologic characteristics despite overlapping unique molecular features. From a therapeutic perspective, identification of tuft cell-like LCNECs might be crucial given their close kinship with tuft cell-like SCLC.

Aberrant synaptophysin expression in classic Hodgkin lymphoma

BackgroundSynaptophysin is an immunohistochemical marker for neuroendocrine differentiation and is widely used in pathologic diagnosis. Its expression in malignant lymphoma has not yet been described. However, we experienced an index case of classic Hodgkin lymphoma with synaptophysin expression. This experience prompted us to investigate synaptophysin expression in classic Hodgkin lymphoma.MethodImmunohistochemical staining of synaptophysin was performed in 59 diagnosed cases of classic Hodgkin lymphoma, 10 anaplastic large cell lymphomas, 16 diffuse large B-cell lymphomas, and 5 extranodal marginal zone lymphoma of the mucosa-associated tissue. Synaptophysin-positive cases were stained for both chromogranin and CD56a.ResultOf 59 classic Hodgkin lymphoma cases, 11 (19%) were positive for synaptophysin. None of the anaplastic large cell lymphomas expressed synaptophysin. Synaptophysin showed weak but specific expression in the cytoplasm of the Hodgkin lymphoma tumor cells. Other background inflammatory cells (such as macrophages, B-, and T-lymphocytes) were all negative for synaptophysin expression. Chromogranin and CD56a were not expressed in the synaptophysin-positive classic Hodgkin lymphomas.ConclusionsSynaptophysin is an integral glycoprotein present in presynaptic vesicles of neurons and neuroendocrine cells. It is a diagnostic marker for neuroendocrine tumors. Aberrant synaptophysin expression has been reported in non-neuroendocrine tumors but not in lymphoma or leukemia. To the best of our knowledge, synaptophysin positivity has only been reported in a single case of precursor T-lymphoblastic leukemia/lymphoma to date. Our study showed that aberrant synaptophysin expression in classic Hodgkin lymphoma is an unexpectedly frequent finding. The mechanism underlying, and prognostic significance of, such aberrant expression is unclear. Thus, in a small biopsy, aberrant synaptophysin expression could be a diagnostic pitfall and should be carefully avoided.

Cytological diagnosis of olfactory neuroblastoma at metastatic sites, with emphasis on role of insulinoma-associated protein 1 immunocytochemistry.

Olfactory neuroblastoma (ONB) is a rare neuroectodermal tumor with a propensity for lymph node and distant metastases in a proportion of cases, presenting opportunities for cytological diagnosis. Insulinoma-associated protein 1 (INSM1) is a recently identified marker of neuroendocrine differentiation with higher sensitivity and specificity than traditional neuroendocrine immunostains used in diagnosis of ONB. Archival aspirates diagnosed as metastatic ONB were retrieved and reviewed for described characteristics of ONB. Spare direct smears with sufficient cellular material from each case were selected, if available, and immunocytochemistry for INSM1 was performed on the destained alcohol-fixed smears. INSM1 was also performed on non-neuroendocrine malignant round cell tumors (MRCT). Seven fine needle aspirates (FNA) from five patients were identified, all of which showed a small round cell tumor with fine to coarse granular chromatin. Most cases had moderate to high cellularity, comprised of loosely cohesive clusters and dispersed cells. While two-cell pattern, nuclear streaking and moulding were frequent, background neuropil, fibrillary cytoplasm, and rosettes were uncommon. INSM1 immunostaining performed on spare direct smears showed strong positivity in 30%-100% of tumor cells (mean: 62%) in all aspirates tested (100%). In comparison with other immunostains, INSM1 showed more robust staining, and was easier to interpret. All non-neuroendocrine MRCTs were negative for INSM1. Metatstatic ONB can resemble other small round cell tumors, as all the diagnostic features of ONB may not be readily evident. INSM1 immunocytochemistry has high sensitivity and specificity and can reliably be used as a single marker to support the cytomorphology for a confirmatory diagnosis of ONB, even on direct smears if a cell block is not available.

Co-Expression of Adaptor Protein FAM159B with Different Markers for Neuroendocrine Cells: An Immunocytochemical and Immunohistochemical Study.

Little is known about the adaptor protein FAM159B. Recently, FAM159B was shown to be particularly expressed in neuroendocrine cells and tissues, such as pancreatic islets and neuroendocrine cells of the bronchopulmonary and gastrointestinal tracts, as well as in different types of neuroendocrine tumours. To gain insights into possible interactions of FAM159B with other proteins and/or receptors, we analysed the co-expression of FAM159B and various neuroendocrine-specific markers in the cancer cell lines BON-1, PC-3, NCI-h82, OH-1, and A431 and also in human pancreatic tissues and pancreatic neuroendocrine tumours. The markers included prominent markers of neuroendocrine differentiation, such as chromogranin A (CgA), neuron-specific enolase (NSE), synaptophysin (SYP), insulinoma-associated protein 1 (INSM1), neural cell adhesion molecule 1 (NCAM1), serotonin (5-HT), somatostatin-14/28 (SST), and several receptors that are typically expressed by neuroendocrine cells, such as dopamine receptor 2 (D2R), somatostatin receptor (SSTR) 1, 2, 3, 4 and 5, and regulator of G-protein signalling 9 (RGS9). FAM159B was expressed evenly throughout the cytosol in all five cancer cell lines. Immunocytochemical and immunohistochemical analyses revealed co-expression of FAM159B with SYP, INSM1, RGS9, D2R, SSTR2, SSTR3, SSTR4, and SSTR5 and strong overlapping co-localisation with NSE. Double-labelling and co-immunoprecipitation Western blot analyses confirmed a direct association between FAM159B and NSE. These results suggest the involvement of FAM159B in several intracellular signalling pathways and a direct or indirect influence on diverse membrane proteins and receptors.

LBMON138 Leg Tumeo: Is It Neuroendocrine Tumor?

Abstract Introduction Neuroendocrine tumors (NETs) are heterogenous group of epithelial neoplasms often known to produce and secrete peptides and bioamines. The presentation varies from symptomatic functional to non-functional tumors. The functional tumors cause symptoms based on the substance secreted: corticotropin, gastrin, glucagon, insulin, norepinephrine, serotonin, somatostatin, etc. The prognosis ranges from well-differentiated tumors being indolent while the poorly differentiated forms are aggressive. We present a case with an atypical presentation of NET which was noted to secrete an atypical hormone, cortisol. Case Presentation A 55-year-old Caucasian man presented with bilateral lower extremity grade 3 pitting edema for past 2 weeks. His past medical history was significant for hypertension. Lower extremity doppler showed no evidence of deep vein thrombosis. Serum potassium was critically low at 1.9mmol/L. Computed tomography of abdomen and pelvis showed a large mass involving the right hepatic lobe, upper pole of right kidney and hypoattenuated lesions in left hepatic lobe. The intrahepatic inferior vena cava appeared to be severely compressed by the mass. MRI abdomen was suggestive of hepatocellular cancer but alfaprotein levels was normal. Biochemical testing for evaluation of hormonal hypersecretion showed elevated cortisol levels (57.2mcg/dl) and markedly elevated dehydroepiandrosterone sulfate (2641mcg/dl). Serum adrenocorticotrophic hormone and aldosterone levels were within normal limits. Low dose dexamethasone suppression test showed no decline in serum cortisol level reflecting adrenal origin. Urinary evaluation showed elevated cortisol but normal metanephrine and catecholamine levels. With concerns for adrenal carcinoma, right adrenal mass biopsy was performed. The biopsy showed poorly differentiated malignant neoplasm with neuroendocrine features. Tumor cells were positive for synaptophysin (a marker for neuroendocrine differentiation) and CD 138. Soon after, he progressed to multisystem organ failure, tumor lysis syndrome and resorted to comfort care. The patient passed away within a week of diagnosis. Conclusion NETs usually originate in gastrointestinal tract, pancreas, adrenal, lung and rarely genitourinary tract. The incidence of NETs is on the rise with increased detection by imaging. Adrenal NETs, well-known as pheochromocytoma are mostly benign but small cell adrenal neuroendocrine carcinomas are rare and have a grave prognosis. Flushing, diarrhea are the commonest presentations (75-85%) for gastrointestinal NETs and symptoms are based on the substance secreted. This case highlights a case of adrenal neuroendocrine cancer presenting with lower extremity swelling and secreting an uncommon hormone, cortisol. Increasing awareness among the medical fraternity will help with early diagnosis and better outcomes. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Pulmonary Large Cell Neuroendocrine Carcinoma.

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare subtype of malignant pulmonary tumor. The incidence rate of LCNEC was reported to be 0.3%–3% in lung cancers. Although LCNEC is classified as non-small cell lung cancer (NSCLC), it is more aggressive and malignant than other NSCLC, and its biological behavior is similar to that of small cell lung cancer (SCLC). Most of the LCNEC patients are elderly smoking male and the clinical manifestations are not specific. The imaging manifestations of the tumors are often located in the periphery and the upper lobes, and the enlargement of mediastinal or hilar lymph nodes is common. The diagnosis is mainly based on pathology by the histological features and immunohistochemistry (IHC). Specific neuroendocrine markers such as chromogranin A (CgA), synaptophysin (Syn) and CD56 are usually diffusely positive in LCNEC, and found that insulinoma-associated protein (INSM1) and high rate of Ki-67 are helpful for diagnosis. More differential diagnoses also increase the difficulty of correctly diagnosing LCNEC. The rise of LCNEC molecular typing in recent years may be helpful for diagnosis and subsequent treatment. This review focuses on the epidemiological features, imaging studies, pathology, diagnosis, treatment, and prognosis of LCNEC.

Activation of neural lineage networks and ARHGEF2 in enzalutamide-resistant and neuroendocrine prostate cancer and association with patient outcomes

BackgroundTreatment-emergent neuroendocrine prostate cancer (NEPC) after androgen receptor (AR) targeted therapies is an aggressive variant of prostate cancer with an unfavorable prognosis. The underlying mechanisms for early neuroendocrine differentiation are poorly defined and diagnostic and prognostic biomarkers are needed.MethodsWe performed transcriptomic analysis on the enzalutamide-resistant prostate cancer cell line C4-2B MDVR and NEPC patient databases to identify neural lineage signature (NLS) genes. Correlation of NLS genes with clinicopathologic features was determined. Cell viability was determined in C4-2B MDVR and H660 cells after knocking down ARHGEF2 using siRNA. Organoid viability of patient-derived xenografts was measured after knocking down ARHGEF2.ResultsWe identify a 95-gene NLS representing the molecular landscape of neural precursor cell proliferation, embryonic stem cell pluripotency, and neural stem cell differentiation, which may indicate an early or intermediate stage of neuroendocrine differentiation. These NLS genes positively correlate with conventional neuroendocrine markers such as chromogranin and synaptophysin, and negatively correlate with AR and AR target genes in advanced prostate cancer. Differentially expressed NLS genes stratify small-cell NEPC from prostate adenocarcinoma, which are closely associated with clinicopathologic features such as Gleason Score and metastasis status. Higher ARGHEF2, LHX2, and EPHB2 levels among the 95 NLS genes correlate with a shortened survival time in NEPC patients. Furthermore, downregulation of ARHGEF2 gene expression suppresses cell viability and markers of neuroendocrine differentiation in enzalutamide-resistant and neuroendocrine cells.ConclusionsThe 95 neural lineage gene signatures capture an early molecular shift toward neuroendocrine differentiation, which could stratify advanced prostate cancer patients to optimize clinical treatment and serve as a source of potential therapeutic targets in advanced prostate cancer.

Prognostic significance of YAP1 expression and its association with neuroendocrine markers in resected pulmonary large cell neuroendocrine carcinoma (LCNEC)

BackgroundYAP1 (Yes-associated protein 1), an important effector of the Hippo pathway, acts as an oncogene and is overexpressed in various malignant tumors. However, the function and expression pattern of YAP1 in pulmonary large cell neuroendocrine carcinoma (LCNEC) have not been systematically established. This study aimed to explore the relationship between YAP1 expression and neuroendocrine differentiation markers and their prognostic significance in LCNEC. Materials and methodsYAP1 protein and neuroendocrine markers (INSM1, NeuroD1 and DLL3) expression were examined by immunohistochemical (IHC) staining in 80 resected pulmonary LCNEC cases. The possible association between these markers and clinicopathological features was evaluated and survival analyses were performed. ResultsYAP1 was highly expressed in 25% LCNECs (20/80) , especially at a relatively higher T stage (p = 0.015). YAP1 expression was negatively correlated with INSM1 (χ2=11.53, p = 0.001) and DLL3(χ2=8.55, p = 0.004), but not with NeuroD1 (p = 0.482). For survival analyses, YAP1 expression was associated with worse disease-free survival (DFS) and overall survival (OS) (median DFS: 13 months vs. not reached (NR), p = 0.0096; median OS: not reached, NR vs. NR, p = 0.038), and was an unfavorable prognostic factor for DFS (HR:3.285; 95%CI: 1.526-7.071, p = 0.002) and OS (HR: 2.864, 95% CI: 0.932-8.796, p = 0.066). ConclusionsYAP1 was found to be conversely correlated with neuroendocrine markers and a prognostic factor for worse survival in resected LCNEC patients, and mechanisms need to be further investigated.