We have previously isolated and sequenced the cDNA of a novel gene, DENN, that exhibits differential mRNA expression in normal and neoplastic cells. The open reading frame of 4761 nucleotides encodes a putative hydrophilic protein of 1587 amino acids with a calculated molecular mass of 176,431 Da. Within DENN cDNA lies an alternative exon segment of 129 nucleotides encoding 43 amino acids, which may be excluded from some transcripts by alternative splicing. The serine- and leucine-rich DENN protein possesses a RGD cellular adhesion motif and a leucine-zipper-like motif associated with protein dimerization, and shows partial homology to the receptor binding domain of tumor necrosis factor alpha. DENN is virtually identical to MADD, a human MAP kinase-activating death domain protein that interacts with type I tumor necrosis factor receptor. DENN displays significant homology to Rab3 GEP, a rat GDP/GTP exchange protein specific for Rab3 small G proteins implicated in intracellular vesicle trafficking. DENN also exhibits strong similarity to Caenorhabditis elegans AEX-3, which interacts with Rab3 to regulate synaptic vesicle release. Composed of 15 exons (ranging in size from 73 to 1230 bp) and 14 introns (varying from about 170 bp to 5.3 kb), the DENN gene is estimated to span at least 28 kb. The alternative splicing event was traced to an alternative 5' donor site involving exon 7. DENN was mapped to chromosome region 11p11.21-p11.22 by FISH. Using polyclonal antibodies against a synthetic peptide, Western blotting of MOLT-4 T-lymphoblastic leukemic cell proteins and immunoblotting of subcellular fractions of MOLT-4 cells and PLC/PRF/5 liver cancer cells yielded data corroborating the alternative splicing mechanism that generates two variant isoforms of the DENN protein that display differential expression in cells of different lineages.

Peripheral T-cell lymphomas not otherwise specified (PTCLs/NOS) are rare and aggressive tumours whose molecular pathogenesis and diagnosis are still challenging. The microRNA (miRNA) profile of 23 PTCLs/NOS was generated and compared with that of normal T-lymphocytes (CD4+, CD8+, naive, activated). The differentially expressed miRNA signature was compared with the gene expression profile (GEP) of the same neoplasms. The obtained gene patterns were tested in an independent cohort of PTCLs/NOS. The miRNA profile of PTCLs/NOS then was compared with that of 10 angioimmunoblastic T-cell lymphomas (AITLs), 6 anaplastic large-cell lymphomas (ALCLs)/ALK+ and 6 ALCLs/ALK-. Differentially expressed miRNAs were validated in an independent set of 20 PTCLs/NOS, 20 AITLs, 19 ALCLs/ALK- and 15 ALCLs/ALK+. Two hundred and thirty-six miRNAs were found to differentiate PTCLs/NOS from activated T-lymphocytes. To assess which miRNAs impacted on GEP, a multistep analysis was performed, which identified all miRNAs inversely correlated to different potential target genes. One of the most discriminant miRNAs was selected and its expression was found to affect the global GEP of the tumours. Moreover, two sets of miRNAs were identified distinguishing PTCL/NOS from AITL and ALCL/ALK-, respectively. The diagnostic accuracy of this tool was very high (83.54%) and its prognostic value validated.

OBJECTIVE

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare group of tumors with a wide spectrum of clinical behavior. However, there are no known clinically relevant biomarkers to predict metastasis.

METHODS

To investigate differential gene expression signatures of metastatic vs non-metastatic NETs, we studied cell cycle regulatory genes in 19 metastatic and 22 non-metastatic colorectal NETs by PCR arrays. Immunohistochemistry (IHC) and quantitative real-time RT-PCR were performed to verify the results and another set of 38 GEP-NETs were further studied for validation.

RESULTS

We first delineated six candidate genes for metastasis including ATM, CCND2, RBL2, CDKN3, CCNB1, and GTSE1. ATM was negatively correlated with metastatic NETs (p<0.001) with more than 2-fold change compared to non-metastatic NETs. Overexpression of ATM protein by IHC was strongly correlated with high ATM mRNA levels and low Ki-67 labeling index. Patients with ATM-negativity by IHC showed significantly decreased overall survival than patients with ATM-positivity (median OS, metastatic vs non-metastatic NETs; 2.7 years vs not reached; p = 0.003) and 85.7% of metastatic NETs were ATM-negative. In another validation set of GEP-NETs, decreased mRNA of ATM gene was associated with metastasis and remained significant (p = 0.023).

CONCLUSIONS

ATM down-regulation was strongly associated with metastatic NETs when compared with non-metastatic NETs and ATM may be a potential predictive marker for metastasis as well as a novel target in metastatic GEP-NETs.

Granulin-epithelin precursor (GEP) is a novel growth factor whose up-regulation we previously reported in 72% of hepatocellular carcinoma (HCC). GEP expression has been reported to be associated with p53 protein accumulation in a breast cancer study, though the p53 mutation status was not revealed. We aim to investigate whether p53 protein and mutation status correlates with GEP expression in HCC. The statistical comparison of p53 and GEP data revealed an overall positive association between the two protein expression patterns (P<0.001). Upon detailed analysis, the association of p53 and GEP protein expression was found to be highly significant only in HCCs with wild-type p53 (P=0.001); there was no association in HCCs with p53 mutation (P=0.669). The GEP levels in the HepG2 hepatoma cell line with a wild-type p53 background were modulated by transfection experiments. Overexpression of the GEP protein resulted in an increased p53 protein level and suppression of the GEP protein resulted in a decreased p53 protein level in HepG2 cells. In summary, we demonstrated that p53 wild-type protein nuclei accumulation is associated with GEP protein expression in human HCC specimens, and GEP modulates p53 wild-type protein levels in vitro.

ADP-ribosylation factors (ARFs) are 20-kDa guanine nucleotide-binding proteins and are active in the GTP-bound state and inactive with GDP bound. ARF-GTP has a critical role in vesicular transport in several cellular compartments. Conversion of ARF-GDP to ARF-GTP is promoted by a guanine nucleotide-exchange protein (GEP). We earlier reported the isolation from bovine brain cytosol of a 700-kDa protein complex containing GEP activity that was inhibited by brefeldin A (BFA). Partial purification yielded an approximately 60-kDa BFA-insensitive GEP that enhanced binding of ARF1 and ARF3 to Golgi membranes. GEP has now been purified extensively from rat spleen cytosol in a BFA-insensitive, approximately 55-kDa form. It activated class I ARFs (ARFs 1 and 3) that were N-terminally myristoylated, but not nonmyristoylated ARFs from class-I, II, or III. GEP activity required MgCl2. In the presence of 0.6-0.8 mM MgCl2 and 1 mM EDTA, binding of guanosine 5'-[gamma[35S]thio]triphosphate ([35S]GTP gamma S) by ARF1 and ARF3 was equally high without and with GEP. At higher Mg2+ concentrations, binding without GEP was much lower; with 2-5 mM MgCl2, GEP-stimulated binding was maximal. The rate of GDP binding was much less than that of GTP gamma S with and without GEP. Phospholipids were necessary for GEP activity; phosphatidylinositol was more effective than phosphatidylserine, and phosphatidic acid was less so. Other phospholipids tested were ineffective. Maximal effects required approximately 200 microM phospholipid, with half-maximal activation at 15-20 microM. Release of bound [35S]GTP gamma S from ARF3 required the presence of both GEP and unlabeled GTP or GTP gamma S; GDP was much less effective. This characterization of the striking effects of Mg2+ concentration and specific phospholipids on the purified BFA-insensitive ARF GEP should facilitate experiments to define its function in vesicular transport.

We previously reported the isolation of the novel human DENN gene, which is differentially expressed in normal and neoplastic cells. DENN is identical to MADD (mitogen-activated protein kinase-activating death domain), which interacts with tumor necrosis factor receptor 1 through their death domains. DENN is also homologous to Rab3 GEP, a rat Rab3 GDP/GTP exchange protein. Real-time reverse transcription-polymerase chain reaction analysis showed that DENN expression in cancer cell lines was 26-50 times that in normal cells. The Jurkat human leukemia, PLC/PRF/5 human hepatoma, and NS-1 mouse myeloma cell lines as well as the MRC-5 human fetal lung and Vero monkey kidney cell lines were treated successfully with four separate DENN-targeted antisense oligodeoxynucleotides (ODNs) to abrogate DENN expression. Quantitative assessment of cell viability and apoptosis by flow cytometry via fluorescein diacetate and propidium iodide membrane-integrity tests, terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate-biotin nick end-labeling, and annexin V assays showed that antisense silencing of DENN resulted in markedly more pronounced cell death in cancer cells compared with nonmalignant cells. Antisense-treated cell lines exhibited extensive loss of DNA content, forming distinct sub-G(1) peaks, while cell proliferation diminished significantly. Ultrastructural features of programmed cell death in cells subjected to antisense ODNs were authenticated by electron microscopy. In contrast, transfection of cell lines with a plasmid construct to achieve DENN overexpression augmented cellular proliferation and could reverse the apoptotic effect of antisense and staurosporine treatment. Our findings suggest that DENN is intimately involved in anti-apoptotic and cell-survival processes.

BACKGROUND

A survey conducted by the German Federal Centre for Health Education in 2012 showed that 35.2% of all young adults (18-25 years) and 12.0% of all adolescents (12-17 years) in Germany are regular cigarette smokers. Most smoked their first cigarette in early adolescence. We recently reported a significantly positive short-term effect of a physician-delivered school-based smoking prevention programme on the smoking behaviour of schoolchildren in Germany. However, physician-based programmes are usually very expensive. Therefore, we will evaluate and optimise Education against Tobacco (EAT), a widespread, low-cost programme delivered by about 400 medical students from 16 universities in Germany.

METHODS

A prospective quasi-experimental study design with two measurements at baseline (t1) and 6 months post-intervention (t2) to investigate an intervention in 10-15-year-olds in grades 6-8 at German secondary schools. The intervention programme consists of two 60-min school-based medical-student-delivered modules with (module 1) and without the involvement of patients with tobacco-related diseases and control groups (no intervention). The study questionnaire measuring smoking status (water pipe and cigarette smoking), smoking-related cognitions, and gender, social and cultural aspects was designed and pre-tested in advance. The primary end point is the prevalence of smokers and non-smokers in the two study arms at 6 months after the intervention. The percentage of former smokers and new smokers in the two groups and the measures of smoking behaviour will be studied as secondary outcome measures.

BACKGROUND

In accordance with Good Epidemiologic Practice (GEP) guidelines, the study protocol was submitted for approval by the responsible ethics committee, which decided that the study does not need ethical approval (Goethe University, Frankfurt-Main, Germany). Findings will be disseminated in peer-reviewed journals, at conferences, within our scientific advisory board and through medical students within the EAT project.

OBJECTIVE

Somatostatin receptor scintigraphy (SRS) is the standard method for the detection of somatostatin receptors (SSTRs). It is commonly used in gastroenteropancreatic neuroendocrine tumor (GEP-NET) staging, and represents the criterion of choice for treatment with somatostatin (SST) analogs. Immunohistochemistry (IHC) was reported as a reliable method for the detection of SSTRs with theoretically superior sensitivity over SRS.

METHODS

We retrospectively analyzed the sensitivity and specificity of IHC in the detection of SSTRs in a cohort of consecutive patients with GEP-NETs attending our Institute from 1997 to 2007. IHC analysis was restricted to SSTR2 and SSTR5, and the results were interpreted according to two different scoring systems. SRS was used as the gold standard. Results. Forty-four patients were enrolled; 24 (55%) had foregut carcinoids, 9 (20%) midgut carcinoids, 2 (5%) hindgut carcinoids, and 9 (20%) had GEP-NETs of unknown primary sites. A high concordance rate between IHC and SRS was shown, irrespective of the IHC scoring system applied (73% and 70%). The sensitivity of IHC was 89.3% and 78.6% and the specificity 43.8% and 50%, depending on the scoring system used.

CONCLUSIONS

Although SSTR2 was shown to be expressed by IHC in up to 50% of tumors not visualized by SRS, SRS still remains the method of choice in the diagnostic and therapeutic management of GEP-NETs. More pathological and clinical data are needed to properly understand the clinical relevance of immunohistochemical detection of SSTR expression in the absence of tumor uptake at SRS.

An increased association between neuroendocrine tumors of the gastrointestinal tract and pancreas (GEP-NET) and other second primary malignancies has been suggested. We determined whether there is indeed an increased risk for second primary malignancies in GEP-NET patients compared with an age- and sex-matched control group of patients with identical malignancies. The series comprised 243 men and 216 women, diagnosed with a GEP-NET between 2000 and 2009 in a tertiary referral center. The timeline, before-at-after diagnosis, and the type of other malignancies were studied using person-year methodology. Poisson distributions were used for testing statistical significance. All data were cross-checked with the Dutch National Cancer Registry. Out of 459 patients with GEP-NET, 67 (13.7%) had a second primary cancer diagnosis: 25 previous cancers (5.4%), 13 synchronous cancers (2.8%), and 29 metachronous cancers (6.3%). The most common types of second primary cancer were breast cancer (n=10), colorectal cancer (n=8), melanoma (n=6), and prostate cancer (n=5). The number of patients with a cancer history was lower than expected, although not significant (n=25 vs n=34.5). The diagnosis of synchronous cancers, mainly colorectal tumors, was higher than expected (n=13 vs n=6.1, P<0.05). Metachronous tumors occurred as frequent as expected (n=29 vs n=25.2, NS). In conclusion, our results are in contrast to previous studies and demonstrate that only the occurrence of synchronous second primary malignancies, mainly colorectal cancers, is increased in GEP-NET patients compared with the general population.

The aim of this study was to assess the clinical sensitivities of the tumor markers chromogranin A (CgA), urinary 5-hydroxyindoleacetic acid (5-HIAA) and alkaline phosphatase (AP) in neuroendocrine tumors (NETs) of the GastroEnteroPancreatic-(GEP-) system depending on tumor primary location and metastatic spread. In a retrospective single-center series, sensitivities were evaluated in serum samples from 110 patients with midgut (n = 62) and pancreatic (n = 48) NETs. CgA levels were analyzed by a commercially-available immunoradiometric assay (CIS-bio) during routine follow-up in the years 2000-2009. CgA showed a higher sensitivity for midgut (68%) than pancreatic (54%) NETs. A higher CgA sensitivity and significantly higher median CgA values were found in patients with liver metastases than in those without, and in patients with hepatic and additionally extra-hepatic metastases than in those with hepatic and nodal metastases alone, respectively. We found an overall sensitivity for elevated 5HIAA excretion of 69% for midgut NETs and a significant correlation between median CgA and 5-HIAA values. The sensitivity of AP and the correlations of AP/CgA-data-pairs were low in both midgut and pancreatic NETs, although highest for metastatic pancreatic NETs. The sensitivity of CgA measurement depends on the NET primary location and spread of disease. 5-HIAA and CgA showed comparable sensitivity in midgut NETs, while AP does not seem to be useful as a tumor marker in GEP-NETs.

The OsWRKY genes play various roles in developmental processes and in stress-related responses in plants. We describe the rice OsWRKY gene expression profiles (GEPs) under control, hormone-treated, and water-deficit treatment (WDT) conditions. The preferential expression of 3 genes was observed in specific tissues, suggesting that these genes may play important roles in the root and panicle stages of growth. To investigate the GEPs in the root and panicle of 3 rice genotypes, we used 2 near-isogenic rice lines from a common genetic combination backcross developed by Aday Selection and IR64. WDTs were applied using the fraction of transpirable soil water (FTSW) for severe, mild, and control conditions. Transcriptomic analysis using a 44K oligoarray from Affymetrix and Agilent was performed on all the tissues. The majority of the OsWRKY genes that were activated were activated in the drought-tolerant IR77298-14-1-2-B-10 line but not in the drought-susceptible IR77298-14-1-2-B-13 or IR64 lines. In IR77298-14-1-2-B-10, non-redundant genes (9) were very specific in their higher expression levels. Approximately 27 and 43% more genes from group III and subgroup IV-a, respectively, were activated in the panicle during severe stress than during the control treatment. We found 5 OsWRKY genes that introgressed in the drought-tolerant IR77298-14-1-2-B-10 line. Os01g43650 was up-regulated in the root under both WDTs and in the panicle under mild stress. OsWRKY up-regulated genes with tissue-specific expression patterns that contained at least 3 cis-elements in the tolerant line. These results provide a useful reference for the cloning of candidate genes for further functional analysis.

To contribute to the innovation of the medical education system in Japan, we visited 35 medical schools and 5 institutes in 12 countries of North America, Europe, Australia and Asia in 2008-2010 and observed the education system. We met the deans, medical education committee and administration affairs and discussed about the desirable education system. We also observed the facilities of medical schools.Medical education system shows marked diversity in the world. There are three types of education course; non-graduate-entry program(non-GEP), graduate-entry program(GEP) and mixed program of non-GEP and GEP. Even in the same country, several types of medical schools coexist. Although the education methods are also various among medical schools, most of the medical schools have introduced tutorial system based on PBL or TBL and simulation-based learning to create excellent medical physicians. The medical education system is variable among countries depending on the social environment. Although the change in education program may not be necessary in Japan, we have to innovate education methods; clinical training by clinical clerkship must be made more developed to foster the training of the excellent clinical physicians, and tutorial education by PBL or TBL and simulation-based learning should be introduced more actively.

BACKGROUND

Positron emission tomography (PET) combined with computer tomography (CT) using (68)Ga-DOTATATE is a promising method for the evaluation of patients with recognised or suspected neuroendocrine tumours (NET). The aim of this study was to assess the diagnostic value of (68)Ga-DOTATATE PET/CT in the visualisation of the expression of somatostatin receptors (SSTR) and identification of new lesions.

METHODS

Between December 2009 and January 2011 ninety-seven patients with confirmed (88 cases) or suspected (9 cases) NET underwent (68)Ga DOTATATE PET/CT. The primary, confirmed or suspected, NET localizations were: GEP tumours--71 patients; medullary thyroid carcinoma--4 patients; cancer of an unknown primary--14 patients; and NET in other localisations--8 patients. PET/CT acquisitions were performed using standard techniques, 45 to 60 minutes after the intravenous injection of 111-185 MBq (68)Ga-DOTATATE.

RESULTS

(68)Ga-DOTATATE PET/CT detected the presence of lesions demonstrating the somatostatin receptor affinity in 50 of the 97 patients (51.5%) and was negative in 47 patients (48.5%). Among 14 patients with metastatic unknown primary cancer, in 5 patients (45.5%) the primary tumour site was identified, and in 4 patients with medullary thyroid cancer distant metastases with SSTR expression were localized in only one patient.

CONCLUSIONS

Our findings confirm the diagnostic role of (68)Ga-DOTATATE PET/CT as an accurate method of identifying primary tumours and distant metastases. It provides information on tumour cell receptors status, which has a significant bearing on planning target radionuclide therapy. Overall, (68)Ga-DOTATATE PET/CT can be used in staging, re-staging, and in regular follow up of oncology patients.

microRNAs (miRNAs) are increasingly recognized as significant players in oncogenesis and tumor biology through post-transcriptional gene regulation impacting broad pathways of proliferation, differentiation, apoptosis, metastasis, and cell survival. Recent studies have found abnormal expression of miRNAs in multiple myeloma (MM). Currently, the precise role of these miRNAs in the biology of MM remains to be elucidated, although they are predicted to be involved in plasma cell proliferation, survival, homing, or in MM cell interactions with the bone marrow microenvironment. Furthermore, a limited number of studies focusing on MM precursor disease (monoclonal gammopathy of undetermined significance [MGUS]) reveal significant differences in miRNA profiles between MGUS and normal plasma cells. Interestingly, several of the microRNAs differentially expressed in MGUS also show aberrant expression in MM, suggesting a role in early myelomagenesis. miRNA profiles can discriminate molecular subtypes of MM that are defined based on gene expression profiling (GEP) and cytogenetic abnormalities, demonstrating the potential diagnostic/prognostic utility of miRNA profiling for subclassification of MM. Given the relative stability of miRNA and ability to isolate miRNA from routine clinical specimens, miRNA analysis promises to facilitate personalized diagnostics and therapies, and to provide insights into the biology of early myelomagenesis.

Gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are rare neoplasms with heterogeneous clinical behavior and potential long-term survival. In 2006/2007, the European Neuroendocrine Tumors Society introduced an important parameter, grade (based on mitoses and Ki-67 proliferation rate), which became part of the latest 2010-WHO classification. Since this is an important tool in the choice of therapeutic algorithm of patients with NETs, our aim was to audit whether retrospective reclassification is possible and feasible and correlate pathological findings with survival. From the histopathology archive, 338 GEP-NETs (1994-2014) were identified, of which 250 were diagnosed pre-2010 and 80 of these have needed, up till now, classification (morphology and grade-mitotic count/Ki-67). Morphology was well differentiated (WD) in 74 cases while only 6 cases were poorly differentiated (PD). Grade was reclassified: G1-45 cases (56 %); G2-28 cases (35 %); G3-7 cases (9 %). Overall survival (OS) in WD NETs was strikingly better compared to PD neoplasms. Differences in OS between grade were statistically significant (p < 0.0001) and, in particular, grade identified a subgroup of patients with WD lesions but with less favorable clinical behavior (OS at 5 years: G1-89 %; G2-48 %; G3-0 %; G1 vs G2 p = 0.03). Feasibility analysis quantified time for reclassification to be between 45 and 64 min/case. Our series confirms the importance of grade in prognostic stratification and underlines that reclassification is feasible, and may prove worthwhile in patient management, especially in view of the potential long survival of patients with NETs and risk of use of inappropriate therapies.

OBJECTIVE

To correlate the baseline and change of chromogranin A (CgA) levels with patient survival and tumor response in Asian patients with advanced gastro-enteropancreatic neuroendocrine tumors (GEP-NETs).

METHODS

Sixty patients with advanced GEP-NET treated in a medical center between April 2010 and April 2013 were enrolled retrospectively. Plasma CgA level was analyzed for correlation with the patient's clinical outcome and tumor response.

RESULTS

Multivariate analysis showed that independent favorable prognostic factors for overall survival were: Eastern Cooperative Oncology Groups performance score 0-1, World Health Organization tumor grade 1-2, single organ metastasis and less than twice the upper normal range of baseline CgA levels. Percentage changes in paired CgA tests (ΔCgA) of more than 17% can predict partial response or stable disease from progressive disease with 91.2% sensitivity and 82.9% specificity.

CONCLUSIONS

Baseline plasma CgA levels predicted overall survival and ΔCgA predicted treatment response in Asian patients with GEP-NETs.

Pancreatic neuroendocrine tumors (pNETs) represent about 7% of all NETs, 8.7% of gastroenteropancreatic NETs (GEP-NETs) and 1-2% of all pancreatic neoplasms. In the last two decades, the increased diagnosis of pNETs has generated great interest and the development of different classifications, grading and staging systems. Recently, several trials were performed in order to improve the knowledge of biomarkers and imaging and to provide an early diagnosis, but their role is still under debate. Nowadays, surgery represents the only curative approach for pNETs. Approximately 90% of pNETs are silent and non-functional; therefore, most patients are diagnosed in late stage and present metastatic (60%) or locally unresectable advanced disease (21%) with a poor prognosis. Not many therapeutic options are available for pNETs, with different treatments for G1-G2 and G3 tumors, because these diseases are still rare and trials are made up of few series of patients. At present, medical treatments is controversial. On these bases, we believe that a multidisciplinary team composed of surgeons, oncologists, endocrinologists, radiation oncologists, radiologists, pathologists and medicals nuclear is required. This paper presents a review of present state-of-the-art in the field of pNETs.

OBJECTIVE

Our purpose was to compare the sensitivity of whole body (WB) magnetic resonance imaging (MRI) and somatostatin receptor scintigraphy (SRS) for the diagnosis of bone metastases (BMs) in patients with well-differentiated gastro-entero-pancreatic endocrine cancer (WD-GEP-EC) and to determine predictive factors of BM.

METHODS

WB-MRI and SRS were prospectively performed in 79 patients with bronchial (11), thymic (five), gastric (two), duodeno-pancreatic (24), ileal (26), colic (one), or unknown primary (10) WD-GEP-EC.

RESULTS

A total of 36 patients (46%) had 333 BMs involving 119 skeletal segments. WB-MRI and SRS were equally sensitive for detecting patients with BM (86 vs. 81%; P = 0.56), with 33% of the patients diagnosed with only one procedure. WB-MRI detected more BMs than SRS (80 vs. 57%; P = 0.017). Compared with SRS, WB-MRI detected more spine BMs (96 vs. 45%; P < 0.001) and tended to detect more pelvic and lower limb BMs (P = 0.054 and P = 0.06, respectively). Compared with WB-MRI, SRS detected more skull BMs (100 vs. 0%; P < 0.001) and tended to detect more rib BMs (P = 0.08). Sternal and upper-limb BMs were equally detected with WB-MRI and SRS (P = 0.32 and P = 0.46, respectively). Bone staging with SRS and spine MRI rather than WB-MRI would have detected 92% of the patients with BMs and 83% of all BMs. The extent of liver involvement and bronchial-thymic primary tumors were independent predictive factors for BM.

CONCLUSIONS

We recommend bone staging with SRS and spine MRI in all patients with bronchial-thymic or unknown primary WD-GEP-EC. In case of duodeno-pancreatic or ileal primary, bone imaging may be restricted to patients with liver metastases.

BACKGROUND

Gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NEN) are relatively rare tumors, not equally distributed in the gastrointestinal system. In 2010, a revised version of the WHO classification of GEP-NENs was published. This study reports for the first time the distribution and characteristics of GEP-NENs in a Lebanese population.

METHODS

This descriptive retrospective study concerns all the digestive neuroendocrine tumors with their characteristics diagnosed in Hotel Dieu de France in Beirut, Lebanon from 2001 to 2012, all the pathology reports being reanalyzed according to the latest WHO 2010 classification. The characteristics and features of GEP-NEN analyzed in this study were age, gender, grade and site.

RESULTS

A total of 89 GEP-NENs were diagnosed, representing 28.2% of all neuroendocrine tumors. The mean age of GEP-NEN patients was 58.7 years and the M/F sex ratio was 1.2. The primary localization was as follows: 21.3%(19) pancreatic, 18% (16) gastric, 15.7% (14) duodenal, 11.2% (10) appendix, 10.1% (9) intestinal, 10.1% (9) colorectal (7.9% colonic and 2.2% rectal), 5.6% (4) hepatic, 2.2% (2) ampulla, 1.1% (1) esophageal and 7.9%(5) NOS digestive (metastatic with unknown primary). Of the 89 patients with GEP-NEN, 56.2% (50) were diagnosed as grade I, 11.2% (10) as grade II, 20.2% (18) as grade III and 12.4% (11) were considered as mixed adeno-neuroendocrine carcinomas (MANEC).

CONCLUSIONS

This study, one of the rare examples based on the 2010 WHO classification of neuroendocrine tumors in the literature, indicates that in the Lebanese population, all duodenal and appendicular tumors are G1 and the majority of MANEC tumors are gastric and pancreatic tumors. Moreover, more duodenal tumors and fewer rectal tumors were encountered in our study compared to European reports.

Metformin is a widely used oral antidiabetic drug with good tolerability. Recent studies suggest that it also possesses adjuvant potent anticancer properties in a variety of tumors. Neuroendocrine tumors (NETs) of the gastro-entero-pancreatic system (GEP) comprise a heterogeneous group of tumors with increasing incidence and limited effective therapeutic options. Here we report the antiproliferative effects of metformin in neuroendocrine tumor cells in vitro. Treatment of human pancreatic BON1, bronchopulmonary NCI-H727, and midgut GOT1 neuroendocrine tumor cells with increasing concentrations of metformin (0.1-10 mM) dose-dependently suppressed cell viability and cell counts. Metformin induced AMPK phosphorylation in pancreatic BON1 and midgut GOT1 but suppressed AMPK activity in bronchopulmonary NCI-H727. Thus, AMPK-dependent and AMPK-independent properties may be operative in NETs of different origin. Metformin suppressed mTORC1 signaling in all three tumor cell types, evidenced by suppression of 4EBP1, pP70S6K, and S6 phosphorylation, and was associated with compensatory AKT activity. We observed induction of ERK phosphorylation in BON1 and NCI-H727 and inhibition of ERK in midgut GOT1 cells, while all three tumor cell types responded with induction of GSK3 phosphorylation. This suggests a central role for GSK3 in metformin-mediated signal transduction. Inhibition of cell proliferation by metformin was associated with apoptosis induction only in midgut GOT1, evidenced by increased subG0/1 fraction and PARP cleavage. These results suggest a potential role of metformin as a (adjuvant) therapeutic for patients with NETs.

We investigated the pre-clinical activities of two novel histone deacetylase inhibitors (HDACi), ITF-A and ITF-B, in a large panel of pre-clinical lymphoma models. The two compounds showed a dose-dependent anti-proliferative activity in the majority of cell lines. Gene expression profiling (GEP) of diffuse large B-cell lymphoma (DLBCL) cells treated with the compounds showed a modulation of genes involved in chromatin structure, cell cycle progression, apoptosis, B-cell signaling, and genes encoding metallothioneins. Cell lines showed differences between the concentrations of ITF-A and ITF-B needed to cause anti-proliferative or cytotoxic activity, and cell cycle and apoptosis genes appeared implicated in determining the type of response. In particular, CDKN1A expression was higher in DLBCL cells that, to undergo apoptosis, required a much higher amount of drug than that necessary to induce only an anti-proliferative effect.In conclusion, the two novel HDACi ITF-A and ITF-B demonstrated anti-proliferative activity across different mature B-cell lymphoma cell lines. Basal CDKN1A levels appeared to be important in determining the gap between HDACi concentrations causing cell cycle arrest and those that lead to cell death.

OBJECTIVE

To describe recent advances in the treatment of gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

METHODS

A review of the published English language literature on GEP-NET therapy with a focus on practice-changing clinical trials.

RESULTS

Somatostatin analog (SSA) treatment remains a cornerstone of GEP-NET therapy, primarily for patients with hormonally functional tumors and midgut carcinoids. The biologic agents everolimus and sunitinib have similar tumor-stabilizing effects in pancreatic NETs and are both approved to treat progressive low-intermediate-grade tumors. Their role in nonpancreatic NETs remains controversial. Cytotoxic chemotherapy is effective against pancreatic NETs, but modern prospective data is lacking. Radiolabeled SSAs will likely become more widely available once phase III randomized studies are completed.

CONCLUSIONS

New treatment options for GEP-NETs have become available and highlight the necessity of developing predictive biomarkers that will allow for appropriate and individualized therapy selection.

Gastro-entero-pancreatic neuroendocrine neoplasia (GEP-NENs) are rare tumors, but their frequency is increasing. Neuroendocrine tumors normally express somatostatin (SST) receptors (SSTR) on cell surface, especially G1 and G2 stage tumors, but they can show a dedifferentiation in their clinical history as they become more aggressive. Somatostatin receptor imaging has previously been performed with a gamma camera using [¹¹¹In]In or [^99mTc]Tc-labelled compounds, while [⁶⁸Ga]Ga-labelled compounds and PET/CT imaging has recently become the gold standard for the diagnosis and management of these tumors. Moreover, in the last few years ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG) PET/CT has emerged as an important tool to define tumor aggressiveness and give relevant prognostic information, particularly when coupled with [⁶⁸Ga]Ga-labelled SST analogues PET/CT. This review focuses on the importance of combined imaging with [⁶⁸Ga]Ga-labelled SST analogues and [¹⁸F]FDG for the management of GEP-NENs.

Identified in 1973, somatostatin (SST) is a cyclic hormone peptide with a short biological half-life. Somatostatin receptors (SSTRs) are widely expressed in the whole body, with five subtypes described. The interaction between SST and its receptors leads to the internalization of the ligand-receptor complex and triggers different cellular signaling pathways. Interestingly, the expression of SSTRs is significantly enhanced in many solid tumors, especially gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). Thus, somatostatin analogs (SSAs) have been developed to improve the stability of the endogenous ligand and so extend its half-life. Radiolabeled analogs have been developed with several radioelements such as indium-111, technetium-99 m, and recently gallium-68, fluorine-18, and copper-64, to visualize the distribution of receptor overexpression in tumors. Internal metabolic radiotherapy is also used as a therapeutic strategy (e.g., using yttrium-90, lutetium-177, and actinium-225). With some radiopharmaceuticals now used in clinical practice, somatostatin analogs developed for imaging and therapy are an example of the concept of personalized medicine with a theranostic approach. Here, we review the development of these analogs, from the well-established and authorized ones to the most recently developed radiotracers, which have better pharmacokinetic properties and demonstrate increased efficacy and safety, as well as the search for new clinical indications.

Keywords: imaging; radiolabeling; radionuclide therapy; radiopharmaceuticals; somatostatin analogs.