Neuroendocrine Subtype Research Articles

Why don't corticotroph tumors always produce Cushing's disease?

Silent corticotroph tumors are a pituitary neuroendocrine tumor subtype of corticotroph lineage that do not clinically express Cushing's disease. The silencing of this type of tumor is not fully understood. The aim of the present study was to delve into the lack of secretory activity, studying the post-transcriptional and post-translational regulation of POMC/ACTH in a series of molecularly identified functioning and silent corticotroph tumors. We analyzed 24 silent corticotroph, 23 functioning corticotroph and 25 silent gonadotroph tumors. We used Sanger sequencing, quantitative real-time PCR and Western blot to analyze genetic alterations in POMC, gene expression of TBX19, NEUROD1, POMC, PCSK1, PCSK2, CPE and PAM and protein expression of POMC, PC1/3, PC2, CPE and PAM. We found different polymorphisms in the POMC gene of corticotroph tumors, some of them related to deficiency of proopiomelanocortin. Silent corticotroph tumors showed lower PC1/3 gene and protein expression than functioning ones, especially compared to micro-functioning corticotroph tumors (all P < 0.05). Moreover, we found a positive correlation between PC2 and CPE gene and protein expression (rho ≥ 0.670, P < 0.009) in silent corticotroph tumors compared with functioning ones. By studying the post-transcriptional and post-translational processing of POMC and ACTH, respectively, in a large series of silent and functioning corticotroph tumors, we found that the lack of secretory activity of these tumors is related to an impaired processing of POMC and a high degradation of ACTH, with the macro-functioning corticotroph tumor behaving as an intermediate state between micro-functioning and silent corticotroph tumors.

Abstract 2772: Recurrent alterations of the TenascinC in highly aggressive neuroendocrine sub-type of prostate cancer

Abstract Introduction: Early detection and prognosis of prostate cancer (CaP) is challenging due to its wide spectrum of biological features. Multi-analytic prognostic marker panels have increased sensitivity than single analytes among the biopsy tests and require advanced bioinformatics platform. We aimed to develop a panel of serum biomarkers using multi-omics approach and further characterized their involvement in prostate cancer progression. In a collaborative study between CPDR, Department of Surgery, USU and Berg Health, serum samples (N=385) were examined by multi-omics (proteomics, lipidomics and metabolomics) and Tenascin C (TNC) was identified as one of the promising markers for disease progression in combination with three other analytes, Apolipoprotein AIV, 1-Methyladenosine and a phosphatidic acid (PA 18:0-22:0). The combination of two clinical features, pathological measurement of T-Stage and Gleason score, along with the four molecular analytes further increased the AUC to 0.89 with a NPV of 0.96 and an odds ratio of 12.4. TNC, an extracellular matrix protein, is poorly studied in prostate cancer, though it is expressed in several cancer tissues such as the breast, lung, colon, and the gastrointestinal tract. Methods: Publically available prostate cancer databases (cBioportal Version 1.17.1, http://www.cbioportal.org/index.do) were queried for TNC, and known driver oncogenes in prostate cancer, ERG, AR and MYC. Results: Publically available prostate cancer databases (cBioPortal) demonstrated alterations (either amplifications or mutations) in TNC in 10 out of 16 datasets. Query of TNC along with the driver oncogenes of prostate tumorigenesis, including ERG, MYC and AR, in the aggressive neuroendocrine prostate cancer (NEPC) tumor whole genome sequencing datasets (N=77) demonstrating significant alterations (predominantly amplifications) in 74% of patient samples. CaP genomic levels TNC (30%) was significantly co-amplified (P &amp;lt; 0.001) with ERG (27%), AR (56%) and MYC (53%). TNC protein expression was detected in all examined prostate cancer cell lines VCaP, LNCaP, PC3 and DU145. Conclusion: Genomic alterations of TNC was thus associated with major oncogenic drivers of CaP, such as ERG, AR and MYC in NEPC genomic datasets. Multi-analyte serum biomarkers offers new opportunities with potential impact on primary treatment and surveillance strategies. Functional involvement of the analytes in disease progression to address their mechanistic link with major CaP oncogenic pathways will be further investigated. Citation Format: Prachi Mishra, Michael Kebish, Jennifer Cullen, Amina Ali, Alagasamy Srinivasan, Inger Rosner, David McLeod, Leonardo Rodrigues, Viatcheslav Akmaev, Rangaprasad Sarangarajan, Shiv Srivastava, Niven Narain, Albert Dobi. Recurrent alterations of the TenascinC in highly aggressive neuroendocrine sub-type of prostate cancer [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 2772.

Retrospective study of neuroendocrine breast cancer cases from a single institution in Québec.

e12588 Background: Within numerous breast cancer types, the neuroendocrine subtype distinguishes itself from the others by its rarity. Most of the actual data comes from European and Asian retrospective studies, whom were mostly published before the 2012 WHO classification. Methods: The aim of our study was to describe a North American cohort of neuroendocrine breast cancer tumors homogenized for the latest WHO classification of 2012. We describe the clinical presentation, diagnostic, therapeutic management and prognosis of our population recensed between 2006 and 2016 at the CHUS in Sherbrooke, Québec. A pathological review of the cases was done to unify the cohort by the latest WHO classification. Results: 59 cases were identified from the 5238 cases of breast cancer evaluated between 2006 and 2016. After review from the pathologist, 9 cases were discarded since they did not meet the diagnostic criterias. 47 patients had invasive breast carcinoma with neuroendocrine differentiation, 4 patients had poorly differentiated/small cell carcinoma and none had well differentiated neuroendocrine tumor. 44 patients were not metastatic whereas 7 patients were metastatic at disease onset with a mean age at diagnosis of 70 and 67 years respectively. 10% (4/44) developed a metastatic disease with a median time of 30 months. The mean size of the tumor was 26,1 mm and had a mean Ki67% of 28,3%. All of our patients were ER+, 98% PR+ and 4% Her2+. None had a triple negative disease. 6 patients were SBR grade 1, 31 were grade 2 and 12 were grade 3. The median follow-up for the non-metastatic patients was 42 months and 23 months for the metastatic patients. The median overall survival of our metastatic cohort was 30 months. The histologic subtype did not statistically influence the overall survival and the progression-free survival. Conclusions: Our study is the largest North American cohort of neuroendocrine breast cancer tumors classified with the latest WHO classification of 2012. More details about each subgroup analysis will be presented at the meeting. Even with this classification, the histologic diagnosis remains challenging. Further studies are needed to better characterize these patients and define their optimal management.

Resection of primary tumor may prolong survival in metastatic gastroenteropancreatic neuroendocrine tumors

Patients with gastroenteropancreatic neuroendocrine tumors often present with stage IV disease. Primary tumor resection in these patients remains controversial. Herein, we studied the impact of primary tumor removal, identified variables associated with prolonged survival for each neuroendocrine tumor subtype, and determined factors that influence surgeons to perform primary tumor resection. Patients with metastatic gastroenteropancreatic neuroendocrine tumors diagnosed from 2004 to 2014 were identified from the National Cancer Database. Nested Cox proportional hazards and logistic regression models were used to assess variables associated with survival and primary resection. A total of 14,510 patients met inclusion criteria. On multivariable analysis, resection of the primary tumor and grade 1 or 2 tumors was associated with prolonged survival in all subtypes (P < .001). Organ-specific variables associated with prolonged survival in patients undergoing primary tumor resection included the following: low grade for all organs; young age for pancreatic, small intestinal, colonic, and rectal neuroendocrine tumor; tumor size for colonic and rectal neuroendocrine tumor; and tumor location for colonic neuroendocrine tumor. Low tumor grade was found to be significantly associated with removal of the primary tumor across all organs. This study is the first suggesting that primary tumor resection is associated with prolonged survival for all gastro-entero-pancreatic NETs. Additional variables related to survival for each NET subtype were identified and might help select patients who benefit from primary tumor removal.

MS32.04 Molecular Phenotypes of SCLC

Heterogeneity of neuroendocrine (NE) differentiation in small cell lung cancer (SCLC) determines very different molecular phenotypes Background and Purpose: SCLC is usually regarded as a homogenous tumor treated in a standard fashion. We have established and validated a 50 gene expression quantitative scoring system for NE lung tumors, consisting of both positive and negative scores [1]. While almost all carcinoid tumors have positive scores, SCLC and large cell neuroendocrine carcinomas have positive and negative subpopulations. Methodology: We utilized the NE gene expression score to demonstrate intertumor heterogeneity of gene expression patterns and their relationship to signaling pathways and to immune and inflammatory response. We used cluster analysis to divide the SCLC samples into high and low NE subtypes. We studied two public SCLC tumor data sets (n = 140) as well as 70 cell lines established by us and a pair of high/low sublines established from a single SCLC cell line. The NE score cluster analysis indicated that ∼10% of cell lines and ∼20 of SCLC tumors were of the low NE subtype. The low NE subtype samples had RB1 mutations or low or absent RB1 expression, confirming their SCLC origin. Differences between the high and low subtypes were divided into those common to tumors and cell lines and those largely or entirely limited to tumors. Differences common to tumors and cell lines: At least three different lineage specific transcription factors were expressed by SCLC tumors and cell lines. Most NE high cells expressed ASCL1 in conjunction with NKX2-1. NEUROD1, occasionally with ASCL1, was expressed by a smaller subset of NE high and occasionally by NE low cells. POU2F3 was expressed by most of the NE low subtypes, and about half of these also expressed ASCL2. However, about 4% of tumors and cell lines (all belonging to the NE low subtype) lacked an identified lineage specific transcription factor. The NE high subtype expressed all of the classic NE markers, as well as numerous neural markers covering neural and glial differentiation. In addition they selectively expressed markers for DNA damage, the FGFR pathway, calcium signaling and Notch inhibitors. The NE low subtype lacked all or most of the NE cell program, NKX2-1 and DLL3 expression, while MYC and REST expression, the Hippo, TGFb and Notch pathways and EMT were greatly upregulated. These and other findings were predicted to impact on the potential responses of the two subtypes to chemotherapy, radiotherapy, and multiple targeted therapies. Differences limited to tumors and absent in cell lines: Despite having a high mutational burden, SCLC is considered to be an “immunological desert”, with few infiltrating immune or inflammatory cells, low or absent PDL-1 expression, and modest responses to PD-1 blockade. While the high NE tumors fitted this description most of the low NE tumors had strands of fibrosis encircling tumor islets, with varying numbers of inflammatory cells in the fibrous strands. Major differences at multiple steps were present in the low NE subtype involving the over 200 genes regulating the Cancer-Immunity Cycle, including the major cytokine families, toll like receptors, the inflammasome pathway, the JAK/STAT pathway, HLA antigens, CD47 antigen, perforin and granzymes. These changes were accompanied by highly significant increases in the relative numbers of multiple types of infiltrating immune and inflammatory cells. In addition, the low NE subtype had increased expression of PDL-1 and the interferon gamma signature, suggesting enhanced responses to immunotherapy. SCLC tumors and cell lines can be divided into high and low NE subtypes and these subtypes have major differences in lineage specific transcription factors, expression of the NE program, as well as some oncogenes and pathways, predicting them to respond very differently to conventional and targeted therapies. In addition, very different infiltrating cellular and gene expression patterns of immune responses were present in the low NE tumors, involving multiple aspects of Innate and Adaptive Immunity, and predicting that the low NE subtype tumors are more likely to respond to immunotherapy. In addition, several possibilities of combining cytotoxic, targeted and immunotherapies are suggested from our findings. I thank my collaborators for their invaluable contributions: Ling Cai, Tao Wang, Guanghua Xiao, Luc Girard and John Minna. Reference: 1. Zhang W, Girard L, Zhang YA, et al. Small cell lung cancer tumors and preclinical models display heterogeneity of neuroendocrine phenotypes. Transl Lung Cancer Res 2018;7(1):32-49.

Abstract B069: Drug response variability between luminal and basal prostate cancer tumors

Abstract Introduction: Prostate cancer (PCa) is a genomically heterogeneous disease that has been subtyped into molecularly distinct subtypes. Over the past several years, multiple drugs have demonstrated improvements in overall survival in men with advanced prostate cancer, prompting further investigations of these drugs. However, characterizing drug response in the localized disease setting and in the context of PCa molecular subtypes needs further investigation. Here in a large prospective cohort of men with adverse pathology we explore the heterogeneity of patient drug response between basal, luminal, and neuroendocrine prostate cancer subtypes. Methods: Whole-transcriptome RNA expression profiles of 9,640 radical prostatectomy (RP) samples from prospective use of the Decipher test were obtained from the GRID registry database. Patients were subtyped into basal, luminal A, luminal B, and neuroendocrine subtypes using the PAM50 and small cell gene expression signatures. Drug response scores (DRS) predicting patient sensitivity for 89 oncology drugs were determined using in vitro drug sensitivity and microarray data from the NCI-60 panel. Pearson’s chi squared test was used to determine significant differences in drug sensitivity among PCa subtypes. Results: Applying the subtype signatures to the cohort, we classified 43% of samples as basal, 26% as luminal A, 30% as luminal B, and 2% as neuroendocrine. DRS was highly variable across the subtypes. Basal tumors showed a distinct drug response profile where basal tumors were more sensitive to kinase inhibitors (e.g., cabozantanib, dasatnib, erlotinib), mTOR inhibitors (e.g., everolimus, temsirolumus), DNA repair inhibitors (e.g., olaparib, mitoxantrone), and alkylating (e.g., cisplatin, carboplatin) chemotherapy. Luminal A and B were more sensitive to steroid inhibition (e.g., abiraterone, tamoxifen) and anti-microtuble (e.g., docetaxel, paclitaxel, vinorelbine) chemotherapy, whereas neuroendocrine had highest DRS for antiproliferative agents (e.g., mitomycin, cytabarine, carmustine, topotecan), Significant differences in average DRS scores in subtypes were observed for all 89 drugs (p&amp;lt;0.001). Conclusion: Prostate cancer subtypes in the localized disease setting have distinct drug response profiles, suggesting that subtyping and DRS scores may be useful for selecting candidates for systemic therapy trials. Citation Format: Robert Den, Jonathan Lehrer, Mandeep Takhar, Mohammed Alshalalfa, Nicholas Erho, Elai Davicioni, Felix Feng. Drug response variability between luminal and basal prostate cancer tumors [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B069.

Is it time to consider the expression of specific-pituitary hormone genes when typifying pituitary tumours?

The aim of the present study is to check whether we can replicate, in an independent series, previous results showing that the molecular study of pituitary-specific gene expression complements the inmunohistochemical identification of pituitary neuroendocrine tumours. We selected 112 patients (51 (46.4%) women; mean age 51.4±16 years; 102 macroadenomas (91.9%), 9 microadenomas (8.1%)) with complete clinical, radiological, immunohistochemical and molecular data from our data set of pituitary neuroendocrine tumours. Patients were different from those previously studied. We measured the expression of the pituitary-specific hormone genes and type 1 corticotrophin-releasing hormone and arginine vasopressin 1b receptors, by quantitative real-time polymerase chain reaction using TaqMan probes. Afterwards, we identified the different pituitary neuroendocrine tumour subtypes following the 2017 World Health Organization classification of pituitary tumours, calculating the concordance between their molecular and immuhistochemical identification. The concordance between molecular and immunohistochemical identification of functioning pituitary neuroendocrine tumours with the clinical diagnosis was globally similar to the previous series, where the SYBR Green technique was used instead of TaqMan probes. Our results also corroborated the poor correlation between molecular and immunohistochemical detection of the silent pituitary neuroendocrine tumour variants. This discrepancy was more remarkable in lactotroph, null-cell and plurihormonal pituitary neuroendocrine tumours. In conclusion, this study validates the results previously published by our group, highlighting a complementary role for the molecular study of the pituitary-specific hormone genes in the typification of pituitary neuroendocrine tumours subtypes.

LMO1 functions as an oncogene by regulating TTK expression and correlates with neuroendocrine differentiation of lung cancer.

LMO1 encodes a protein containing a cysteine-rich LIM domain involved in protein–protein interactions. Recent studies have shown that LMO1 functions as an oncogene in several cancer types, including non-small cell lung cancer (NSCLC). However, the function of LMO1 in other histological subtypes of lung cancer, such as small cell lung cancer (SCLC), was not investigated. In analyzing the expression of LMO1 across a panel of lung cell lines, we found that LMO1 expression levels were significantly and dramatically higher in SCLC cells, an aggressive neuroendocrine subtype of lung cancer, relative to NSCLC and normal lung cells. In NSCLC cells, LMO1 mRNA levels were significantly correlated with expression of neuroendocrine differentiation markers. Our in vitro investigations indicated that LMO1 had the general property of promoting cell proliferation in lung cancer cells representing different histological subtypes, suggesting a general oncogenic function of LMO1 in lung cancer. In investigating the clinical relevance of LMO1 as an oncogene, we found that a high tumor level of the LMO1 mRNA was an independent predictor of poor patient survival. These results suggest that LMO1 acts as an oncogene, with expression correlated with neuroendocrine differentiation of lung cancer, and that it is a determinant of lung cancer aggressiveness and prognosis. By combining gene expression correlations with patient survival and functional in vitro investigations, we further identified TTK as mediating the oncogenic function of LMO1 in lung cancer cells.

Abstract 3514: Differential metabolic targeting of PDAC cells with Zaprinast

Abstract Many pancreatic cancers consume excessive glutamine as a preferable source for anaplerosis, maintenance of proper redox state, and synthesis of intermediates for cancer cell growth and proliferation. Abrogating glutamine metabolism is under investigation to inhibit the proliferation/ growth of glutamine-addicted cancers. In addition, inhibition of the mitochondrial pyruvate carrier (MPC1) can potentially induce cancer cells to become more dependent on glutaminolysis. In this regard, Zaprinast, originally developed as a phosphodiesterase 5 (PDE5) inhibitor, has recently been identified as an inhibitor of both glutaminase as well as MPC1. We compared the growth inhibition effect of Zaprinast against BPTES, a targeted glutaminase inhibitor, and UK5099, a targeted MPC1 inhibitor, as well as the combination of BPTES and UK5099. Using pancreatic ductal adenocarcinoma (PDAC) cells, KRAS mutant (Mia Paca2) and KRAS wildtype (Panc03.27), KRAS mutant neuroendocrine (QGP1), and normal pancreatic epithelial cells (HPNE), Zaprinast alone showed more potent growth inhibition in all tested cells lines than single agent treatment with BPTES or UK5099. Further, Zaprinast effectively depleted mitochondrial reserve respiratory capacity similar to UK5099, rendering mitochondria more vulnerable to oxidative stress or pharmacological inhibitors targeting the electron transport chain. In addition, Zaprinast treatment of cancer cells differentially elevated ROS levels greater than 10-fold compared to normal HPNE cells (ROS levels: Mia Paca2 ~ Panc03.27 &amp;gt; QGP1 &amp;gt; HPNE). However, the increase in ROS levels did not correlate with Zaprinast-induced growth inhibition (IC50: Mia Paca2=300 µM, Panc03.27=110 µM, HPNE=650 µM, QGP1 &amp;gt;1 mM). Although Zaprinast-induced growth inhibition was selective toward adenocarcinoma cells but not the neuroendocrine subtype, the selective Zaprinast-induced elevation of ROS levels toward all cancer subtypes renders possibilities for potential synthetic lethality when combined with other metabolic inhibitors. Citation Format: Yi Rao, Seth Gammon, David Piwnica-Worms. Differential metabolic targeting of PDAC cells with Zaprinast [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3514.

Abstract 5020: A patient-derived organoid model of neuroendocrine prostate cancer transdifferentiation informing the role of the BAF complex component ARID1A

Abstract Metastatic castration-resistant prostate cancer (mCRPC) is a genetically and phenotypically heterogeneous disease. Resistance to contemporary androgen-deprivation therapy (ADT) is inevitable, and occurs via several different mechanisms. One of these is lineage plasticity leading to transdifferentiation of AR-positive adenocarcinoma (ACPC) to the neuroendocrine (NEPC) subtype. The modern era of second-generation ADT has seen a significant increase in the percentage of NEPC, yet little is known about the genetic and epigenetic drivers of this phenotype. Using modified organoid media conditions that we previously developed, we have established a set of mCRPC organoid lines derived from four biopsies (two samples before and two after carboplatin + etoposide treatment, 1 year apart) of a single patient tumor that capture the genetic and phenotypic heterogeneity of the original metastatic tumor. Genomic and histologic analysis show that the original patient tumor is composed of both adenocarcinoma and neuroendocrine subpopulations that are maintained in the organoids at a ratio of approximately 1:4, respectively. The two subpopulations share a common ancestor and a putative early driver event in the homozygous loss of CDKN1B, but our analysis of clonal evolution indicates that the majority NEPC population did not transdifferentiate directly from the minority ACPC population in the metastasis, but rather in the primary tumor or in a prior metastatic lesion. The ACPC subpopulation contains a high copy gain of an upstream regulatory region of the AR gene and is genetically distinct from the NEPC population that lacks this alteration, but uniquely contains a truncating mutation in the ARID1A gene. ARID1A is frequently mutated and/or deleted in several different cancer types. It has been found to be altered in ~2% of prostate cancer patients, but its role is not understood. It is a key component of the BAF complex, which is a known regulator of neural development. Immunofluourescent staining of our organoid cells shows that mutant ARID1A correlates with the NEPC population. Using single-cell RNA-seq and principle component clustering analysis, we have identified five different transcriptionally defined populations: one population that corresponds to the genetically defined ACPC population and four additional transcriptionally defined populations that represent different states of differentiation of the NEPC component, as determined by expression of lineage markers. A full understanding of this model with respect to differentiation of the NEPC population and the specific role of ARID1A in the process will inform the development of mechanism-based treatments to inhibit NEPC formation. Citation Format: Mike L. Beshiri, Caitlin M. Tice, Adam G. Sowalsky, Crystal Tran, Fatima Karzai, William Dahut, Kathy Kelly. A patient-derived organoid model of neuroendocrine prostate cancer transdifferentiation informing the role of the BAF complex component ARID1A [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5020.

Small cell lung cancer tumors and preclinical models display heterogeneity of neuroendocrine phenotypes.

Small cell lung cancer (SCLC) is a deadly, high grade neuroendocrine (NE) tumor without recognized morphologic heterogeneity. However, over 30 years ago we described a SCLC subtype with "variant" morphology which did not express some NE markers and exhibited more aggressive growth. To quantitate NE properties of SCLCs, we developed a 50-gene expression-based NE score that could be applied to human SCLC tumors and cell lines, and genetically engineered mouse (GEM) models. We identified high and low NE subtypes of SCLC in all of our sample types, and characterized their properties. We found that 16% of human SCLC tumors and 10% of SCLC cell lines were of the low NE subtype, as well as cell lines from the GEM model. High NE SCLC lines grew as non-adherent floating aggregates or spheroids while Low NE lines had morphologic features of the variant subtype and grew as loosely attached cells. While the high NE subtype expressed one of the NE lineage master transcription factors ASCL1 or NEUROD1, together with NKX2-1, the entire range of NE markers, and lacked expression of the neuronal and NE repressor REST, the low NE subtype had lost expression of most NE markers, ASCL1, NEUROD1 and NKX2-1 and expressed REST. The low NE subtype had undergone epithelial mesenchymal transition (EMT) and had activated the Notch, Hippo and TGFβ pathways and MYC oncogene . Importantly, the high and low NE group of SCLC lines had similar gene expression profiles as their SCLC tumor counterparts. SCLC tumors and cell lines can exhibit distinct inter-tumor heterogeneity with respect to expression of NE features. Loss of NE expression results in major alterations in morphology, growth characteristics, and molecular properties. These findings have major clinical implications as the two subtypes are predicted to have very different responses to targeted therapies.

MTE 10.02 Bridging the Gap between Genomics and Clinics

Small cell lung cancer (SCLC) is a neuroendocrine subtype of lung cancer characterized by a fast growth rate, extensive dissemination, and rapid resistance to chemotherapy. Survival rates are dismal and have not significantly improved in the past few decades. Sequencing the genomes of over 100 human SCLC demonstrates universal inactivation of p53 and RB and identified inactivating recurrent mutations in NOTCH family genes.1 Accordingly, we found that activation of Notch signaling in a pre-clinical SCLC mouse model dramatically reduces the number of tumors and extends the survival of the mutant mice.

Cathepsin K expression in castration-resistant prostate carcinoma: a therapeutical target for patients at risk for bone metastases.

The lysosomal cysteine protease cathepsin K is involved in bone remodeling and is also expressed in the peritumoral stroma of carcinomas arising from different organs. A new generation of cathepsin K inhibitors blocking the RANKL/RANK pathway are being developed. We sought to investigate cathepsin K expression in a cohort of castration-resistant prostate carcinomas. Sixteen cases of castration-resistant disease with at least 5 years of follow-up were selected from a cohort of 280 patients who underwent surgery. Cathepsin K was evaluated on formalin-fixed and paraffin-embedded tissue microarrays with 5 tissue spots per case. These were scored as high 2+ (≥30% of cells), low 1+ (<30% of cells) or zero (absence), distinguishing tumor cells and peritumoral stroma cells. Low (1+) and absence (0) of scoring were interpreted as negative, and high (2+) as positive. The castration-resistant group was composed of 15 acinar adenocarcinomas and 1 neuroendocrine carcinoma, and all showed at least Gleason score 8 at prostatectomy. Two out of 16 cases (12%) scored positive for cathepsin K in tumor cells; and 5 of 16 cases (31%) scored positive in peritumoral stroma cells. The neuroendocrine and acinar subtypes of carcinoma with positive immunoexpression in neoplastic cells developed bone metastases after 4 and 5 years, respectively, and subsequently died. Patients affected by castration-resistant prostate carcinoma may be tested for cathepsin K, and a positive strong expression (2+) could be a useful predictive biomarker of response to targeted agents, aiding in the selection of patients eligible for these treatments.

MYC Drives Progression of Small Cell Lung Cancer to a Variant Neuroendocrine Subtype with Vulnerability to Aurora Kinase Inhibition

Loss of the tumor suppressors RB1 and TP53 and MYC amplification are frequent oncogenic events in small cell lung cancer (SCLC). We show that Myc expression cooperates with Rb1 and Trp53 loss in the mouse lung to promote aggressive, highly metastatic tumors, that are initially sensitive to chemotherapy followed by relapse, similar to human SCLC. Importantly, MYC drives a neuroendocrine-low "variant" subset of SCLC with high NEUROD1 expression corresponding to transcriptional profiles of human SCLC. Targeted drug screening reveals that SCLC with high MYC expression is vulnerable to Aurora kinase inhibition, which, combined with chemotherapy, strongly suppresses tumor progression and increases survival. These data identify molecular features for patient stratification and uncover a potential targeted treatment approach for MYC-driven SCLC.

Treatment of lung large cell neuroendocrine carcinoma

Lung large cell neuroendocrine carcinoma (L-LCNEC) is a rare, aggressive, and difficult-to-treat tumor. It is classified as a neuroendocrine subtype of large cell lung carcinoma (LCLC) belonging to the non-small cell lung cancer (NSCLC) group, but it is also included in the neuroendocrine tumor (NET) group. Most of the available data related to its treatment derive from retrospective analyses or small case series. For patients with L-LCNEC, prognosis is generally very poor. In early stages (I-II-III), surgery is recommended but does not seem to be sufficient. Platinum-based adjuvant chemotherapy may be useful while the role of neoadjuvant chemotherapy is still not well defined. In patients with advanced L-LCNEC, the chemotherapy regimens used in SCLC still remain the standard of treatment, but results are not satisfactory. Due to their peculiar clinical and biological features and the lack of literature data, there is an emerging need for a consensus on the best treatment strategy for L-LCNEC and for the identification of new therapeutic options. In this review, we will discuss the key aspects of L-LCNEC management with the aim to clarify the most controversial issues.

Neurodevelopmental origin and adult neurogenesis of the neuroendocrine hypothalamus.

The adult hypothalamus regulates many physiological functions and homeostatic loops, including growth, feeding and reproduction. In mammals, the hypothalamus derives from the ventral diencephalon where two distinct ventricular proliferative zones have been described. Although a set of transcription factors regulating the hypothalamic development has been identified, the exact molecular mechanisms that drive the differentiation of hypothalamic neural precursor cells (NPCs) toward specific neuroendocrine neuronal subtypes is yet not fully disclosed. Neurogenesis has been also reported in the adult hypothalamus at the level of specific niches located in the ventrolateral region of ventricle wall, where NPCs have been identified as radial glia-like tanycytes. Here we review the molecular and cellular systems proposed to support the neurogenic potential of developing and adult hypothalamic NPCs. We also report new insights on the mechanisms by which adult hypothalamic neurogenesis modulates key functions of this brain region. Finally, we discuss how environmental factors may modulate the adult hypothalamic neurogenic cascade.

Near-perfect concordance between immunoperoxidase (IPX) and bright field in-situ hybridisation (ISH) in HER2 positive and negative breast carcinoma. are we wasting money?

Aim To determine concordance between HER2 IPX and ISH, and consider health economics implication in two metropolitan public hospitals (Hospital A and Hospital B). Methods 584 cases of breast cancer [ n =214 (Hospital A); n =370 (Hospital B)] were examined. Hospital A had ISH performed at a tertiary referral institution. Dual-probe ISH was arranged for equivocal single-probe ISH. Hospital B had in-house double-probe ISH. Results Cases were grouped into positive (HER2 3+) and negative (HER2 1+/0) ( n =549) or equivocal (HER2 2+) ( n =35). In Hospital A, discordance was re-evaluated by an independent pathologist using dual-probe ISH. Four ( n =4) were initially discordant, all with negative IPX and amplified single-probe ISH. Despite re-evaluation, one ( n =1) remained discordant. This was an invasive carcinoma with neuroendocrine differentiation. In Hospital B, one ( n =1) was discordant, with negative IPX and amplified double-probe ISH. Subsequent fluorescent ISH showed non-amplification. This was an invasive carcinoma, no special type. Conclusion Our study demonstrates 99.6% concordance between HER2 IPX and ISH. Dual-probe ISH is a more accurate ISH method. Although further studies are needed, we suggest that breast cancer with positive or negative IPX should not require ISH confirmation, unless in rare neuroendocrine subtypes or in cases with histopathological concerns. Cost savings would be significant. Hospital A alone would save more than AUD 28,000/annum, according to Medicare scheduling.

Tu1845 In Functional Dyspepsia, Are Meal-Related Symptoms Linked to Less Drinking Capacity?

Background: Serotonin (5-HT) signaling in the small intestine is involved in motor, sensory and secretory pathways. Studies of neuroendocrine cell mapping in functional dyspepsia (FD), characterized by upper gastrointestinal motor and sensory disturbances, are scarce although it has been previously noted that there is no significant difference in numbers of 5HT cells in duodenum in post infectious FD vs. controls1. In patients with irritable bowel syndrome, another functional bowel disorder, a low density of duodenal neuroendocrine cells is also described2. Aim: To examine the content of neuroendocrine cells in the duodenum of subjects with FD, specifically the relative content of serotonin (5-HT) containing cells and to investigate a possible relationship between neuroendocrine cell numbers and FD subtypes. Methods: A random sample of an adult Swedish population (n = 1000) (the Kalixanda study) underwent upper endoscopy and biopsies taken from the duodenal bulb (D1) and the second part of duodenum (D2). From this study 23 subjects with FD were identified, 13 with postprandial distress syndrome (PDS), 10 with epigastric pain syndrome (EPS) and 12 healthy controls. Immunocytochemistry was performed for Chromogranin A (CGA) and 5-HT. Positive cells were quantified per mm2. Results: Cases and controls showed similar demographics. The number of CGA stained cells was significantly lower in FD patients both in D1 (p = 0.01) and D2 (p = 0.04) whereas there was no significant difference in 5-HT content. See figure. When EPS and PDS were studied separately, the number of CGA stained cells was significantly decreased in D1 in patients with EPS (p = 0.03). Conclusions: The number of duodenal neuroendocrine cells is decreased in FD compared with control subjects, but this is not due to a reduction in the number of 5-HT containing cells. It is possible that this reduction reflects reduced cellular densities of other hormones (e.g. somatostatin) which could result in a high secretion of gastric acid, with a change in motility or visceral sensitivity leading to dyspeptic symptoms in these cases. 1. Futagami S et al. Am J Gastroenterol. 2010 ;105:1835-42. 2. El-Salhy M et al. Scand J Gastroenterol. 2010 ;45:1435-9.

Tu1842 Neuroendocrine Cells in the Duodenum in Functional Dyspepsia

Background: Serotonin (5-HT) signaling in the small intestine is involved in motor, sensory and secretory pathways. Studies of neuroendocrine cell mapping in functional dyspepsia (FD), characterized by upper gastrointestinal motor and sensory disturbances, are scarce although it has been previously noted that there is no significant difference in numbers of 5HT cells in duodenum in post infectious FD vs. controls1. In patients with irritable bowel syndrome, another functional bowel disorder, a low density of duodenal neuroendocrine cells is also described2.Aim: To examine the content of neuroendocrine cells in the duodenum of subjects with FD, specifically the relative content of serotonin (5-HT) containing cells and to investigate a possible relationship between neuroendocrine cell numbers and FD subtypes. Methods: A random sample of an adult Swedish population (n = 1000) (the Kalixanda study) underwent upper endoscopy and biopsies taken from the duodenal bulb (D1) and the second part of duodenum (D2). From this study 23 subjects with FD were identified, 13 with postprandial distress syndrome (PDS), 10 with epigastric pain syndrome (EPS) and 12 healthy controls. Immunocytochemistry was performed for Chromogranin A (CGA) and 5-HT. Positive cells were quantified per mm2. Results: Cases and controls showed similar demographics. The number of CGA stained cells was significantly lower in FD patients both in D1 (p = 0.01) and D2 (p = 0.04) whereas there was no significant difference in 5-HT content. See figure. When EPS and PDS were studied separately, the number of CGA stained cells was significantly decreased in D1 in patients with EPS (p = 0.03). Conclusions: The number of duodenal neuroendocrine cells is decreased in FD compared with control subjects, but this is not due to a reduction in the number of 5-HT containing cells. It is possible that this reduction reflects reduced cellular densities of other hormones (e.g. somatostatin) which could result in a high secretion of gastric acid, with a change in motility or visceral sensitivity leading to dyspeptic symptoms in these cases. 1. Futagami S et al. Am J Gastroenterol. 2010 ;105:1835-42. 2. El-Salhy M et al. Scand J Gastroenterol. 2010 ;45:1435-9.

Tu1844 Symptom Stability and Economic Burden in Patients With Functional Dyspepsia: Observational 12 Month Follow-Up After a Short-Term Clinical Trial

Background: Serotonin (5-HT) signaling in the small intestine is involved in motor, sensory and secretory pathways. Studies of neuroendocrine cell mapping in functional dyspepsia (FD), characterized by upper gastrointestinal motor and sensory disturbances, are scarce although it has been previously noted that there is no significant difference in numbers of 5HT cells in duodenum in post infectious FD vs. controls1. In patients with irritable bowel syndrome, another functional bowel disorder, a low density of duodenal neuroendocrine cells is also described2.Aim: To examine the content of neuroendocrine cells in the duodenum of subjects with FD, specifically the relative content of serotonin (5-HT) containing cells and to investigate a possible relationship between neuroendocrine cell numbers and FD subtypes. Methods: A random sample of an adult Swedish population (n = 1000) (the Kalixanda study) underwent upper endoscopy and biopsies taken from the duodenal bulb (D1) and the second part of duodenum (D2). From this study 23 subjects with FD were identified, 13 with postprandial distress syndrome (PDS), 10 with epigastric pain syndrome (EPS) and 12 healthy controls. Immunocytochemistry was performed for Chromogranin A (CGA) and 5-HT. Positive cells were quantified per mm2. Results: Cases and controls showed similar demographics. The number of CGA stained cells was significantly lower in FD patients both in D1 (p = 0.01) and D2 (p = 0.04) whereas there was no significant difference in 5-HT content. See figure. When EPS and PDS were studied separately, the number of CGA stained cells was significantly decreased in D1 in patients with EPS (p = 0.03). Conclusions: The number of duodenal neuroendocrine cells is decreased in FD compared with control subjects, but this is not due to a reduction in the number of 5-HT containing cells. It is possible that this reduction reflects reduced cellular densities of other hormones (e.g. somatostatin) which could result in a high secretion of gastric acid, with a change in motility or visceral sensitivity leading to dyspeptic symptoms in these cases. 1. Futagami S et al. Am J Gastroenterol. 2010 ;105:1835-42. 2. El-Salhy M et al. Scand J Gastroenterol. 2010 ;45:1435-9.