The RHO1 gene encodes a homolog of the mammalian RhoA small GTP binding protein in the yeast Saccharomyces cerevisiae. Rho1p is localized at the growth site and is required for bud formation. Multicopy suppressors of a temperature-sensitive, dominant negative mutant allele of RHO1, RHO1(G22S, D125N), were isolated and named ROM (RHO1 multicopy suppressor). Rom1p and Rom2p were found to contain a DH (Dbl homologous) domain and a PH (pleckstrin homologous) domain, both of which are conserved among the GDP/GTP exchange proteins (GEPs) for the Rho family small GTP binding proteins. Disruption of ROM2 resulted in a temperature-sensitive growth phenotype, whereas disruption of both ROM1 and ROM2 resulted in lethality. The phenotypes of deltarom1deltarom2 cells were similar to those of deltarho1 cells, including growth arrest with a small bud and cell lysis. Moreover, the temperature-sensitive growth phenotype of deltarom2 was suppressed by overexpression of RHO1 or RHO2, but not of CDC42. The glutathione-S-transferase (GST) fusion protein containing the DH domain of Rom2p showed the lipid-modified Rholp-specific GDP/GTP exchange activity which was sensitive to Rho GDP dissociation inhibitor. These results indicate that Rom1p and Rom2p are GEPs that activate Rho1p in S.cerevisiae.

BACKGROUND

The discovery of somatostatin (SST) and the synthesis of a variety of analogues constituted a major therapeutic advance in the treatment of gastroenteropancreatic neuroendocrine (carcinoid) tumours (GEP-NETs). They currently provide the most efficient treatment to achieve symptomatic relief and have recently been demonstrated to inhibit tumour growth.

OBJECTIVE

To review 35 years of experience regarding the clinical application and efficacy of SST analogues.

METHODS

The PubMed database (1972-2009) was searched using somatostatin as a search term with combinations of terms including 'treatment'; 'neuroendocrine'; 'carcinoid'; 'tumor'; 'octreotide'; 'lanreotide' and 'pasireotide'.

RESULTS

In a review of 15 studies including 481 patients, the slow-release formulations Sandostatin LAR and Somatuline SR/Autogel achieved symptomatic relief in 74.2% (61.9-92.8%) and 67.5% (40.0-100%), biochemical response in 51.4% (31.5-100%) and 39.0% (17.9-58%), and tumour response in 69.8% (47.0-87.5%) and 64.4% (48.0-87.0%) respectively. Novel SST analogues like SOM230 (pasireotide) that exhibit pan SST receptor activity and analogues with high affinity to specific somatostatin receptor (sstr) subtypes may further advance the field, but efficacy studies are lacking.

CONCLUSIONS

As more precise understanding of NET cell biology evolves and molecular biological tools advance, more accurate identification of individual tumours sstr profile will probably facilitate a more precise delineation of SST analogue treatment.

The Total Therapy 3 trial 2003-33 enrolled 303 newly diagnosed multiple myeloma patients and was noted to provide superior clinical outcomes compared with predecessor trial Total Therapy 2, especially in gene expression profiling (GEP)-defined low-risk disease. We report here on the results of successor trial 2006-66 with 177 patients, using bortezomib, lenalidomide, and dexamethasone maintenance for 3 years versus bortezomib, thalidomide, and dexamethasone in year 1 and thalidomide/dexamethasone in years 2 and 3 in the 2003-33 protocol. Overall survival (OS) and event-free survival (EFS) plots were super-imposable for the 2 trials, as were onset of complete response and complete response duration (CRD), regardless of GEP risk. GEP-defined high-risk designation, pertinent to 17% of patients, imparted inferior OS, EFS, and CRD in both protocols and, on multivariate analysis, was the sole adverse feature affecting OS, EFS, and CRD. Mathematical modeling of CRD in low-risk myeloma predicted a 55% cure fraction (P < .001). Despite more rapid onset and higher rate of CR than in other molecular subgroups, CRD was inferior in CCND1 without CD20 myeloma, resembling outcomes in MAF/MAFB and proliferation entities. The robustness of the GEP risk model should be exploited in clinical trials aimed at improving the notoriously poor outcome in high-risk disease.

Growth-regulated cells, such as 3T3 mouse embryo fibroblasts (MEFs), require more than one growth factor for growth, usually the insulin-like growth factor I (IGF-I) in combination with either platelet-derived growth factor or epidermal growth factor. Singly, these growth factors cannot sustain the growth of 3T3 cells. However, if the IGF-I receptor (IGF-IR) is even modestly overexpressed, then IGF-I, by itself, stimulates the growth of MEFs in monolayer and makes them capable of forming colonies in soft agar. The granulin/epithelin precursor (GEP) has been identified as the only growth factor, thus far, that can stimulate by itself the growth of R- cells, a 3T3-like cell line in which the genes for the IGF-IR have been deleted. We have expressed GEP in R- cells and show that these cells can now grow in serum-free medium. GEP, however, cannot replace other functions of the IGF-IR, such as protection from apoptosis (anoikis) or transforming activity (colony formation in soft agar). GEP activates, in R- cells, the two signaling pathways that are known to be sufficient for IGF-I-mediated mitogenesis in cells overexpressing the IGF-IR, the mitogen-activated protein kinase and the phosphatidylinositol 3-kinase pathways. This may explain why GEP, by itself, can replace the IGF-IR for growth in monolayer cultures. It also confirms that, for transformation, other pathways must be activated besides the two pathways that are sufficient for mitogenesis.

Diffuse large B-cell lymphomas (DLBCLs) can be divided into germinal-center B cell-like (GCB) and activated-B cell-like (ABC) subtypes by gene-expression profiling (GEP), with the latter showing a poorer outcome. Although this classification can be mimicked by different immunostaining algorithms, their reliability is the object of controversy. We constructed tissue microarrays with samples of 157 DLBCL patients homogeneously treated with immunochemotherapy to apply the following algorithms: Colomo (MUM1/IRF4, CD10, and BCL6 antigens), Hans (CD10, BCL6, and MUM1/IRF4), Muris (CD10 and MUM1/IRF4 plus BCL2), Choi (GCET1, MUM1/IRF4, CD10, FOXP1, and BCL6), and Tally (CD10, GCET1, MUM1/IRF4, FOXP1, and LMO2). GEP information was available in 62 cases. The proportion of misclassified cases by immunohistochemistry compared with GEP was higher when defining the GCB subset: 41%, 48%, 30%, 60%, and 40% for Colomo, Hans, Muris, Choi, and Tally, respectively. Whereas the GEP groups showed significantly different 5-year progression-free survival (76% vs 31% for GCB and activated DLBCL) and overall survival (80% vs 45%), none of the immunostaining algorithms was able to retain the prognostic impact of the groups (GCB vs non-GCB). In conclusion, stratification based on immunostaining algorithms should be used with caution in guiding therapy, even in clinical trials.

We evaluated concurrent gene mutations, clinical outcome, and gene expression signatures of CCAAT/enhancer binding protein alpha (CEBPA) double mutations (CEBPA(dm)) versus single mutations (CEBPA(sm)) in 1182 cytogenetically normal acute myeloid leukemia (AML) patients (16-60 years of age). We identified 151 (12.8%) patients with CEBPA mutations (91 CEBPA(dm) and 60 CEBPA(sm)). The incidence of germline mutations was 7% (5 of 71), including 3 C-terminal mutations. CEBPA(dm) patients had a lower frequency of concurrent mutations than CEBPA(sm) patients (P < .0001). Both, groups were associated with a favorable outcome compared with CEBPA(wt) (5-year overall survival [OS] 63% and 56% vs 39%; P < .0001 and P = .05, respectively). However, in multivariable analysis only CEBPA(dm) was a prognostic factor for favorable OS outcome (hazard ratio [HR] 0.36, P < .0001; event-free survival, HR 0.41, P < .0001; relapse-free survival, HR 0.55, P = .001). Outcome in CEBPA(sm) is dominated by concurrent NPM1 and/or FLT3 internal tandem duplication mutations. Unsupervised and supervised GEP analyses showed that CEBPA(dm) AML (n = 42), but not CEBPA(sm) AML (n = 18), expressed a unique gene signature. A 25-probe set prediction signature for CEBPA(dm) AML showed 100% sensitivity and specificity. Based on these findings, we propose that CEBPA(dm) should be clearly defined from CEBPA(sm) AML and considered as a separate entity in the classification of AML.

Transcriptome study in neurodegenerative disease has advanced considerably in the past 5 years. Increasing scientific rigour and improved analytical tools have led to more-reproducible data. Many transcriptome analysis platforms assay the expression of the entire genome, enabling a complete biological context to be captured. Gene expression profiling (GEP) is, therefore, uniquely placed to discover pathways of disease pathogenesis, potential therapeutic targets, and biomarkers. This Review summarizes microarray human GEP studies in the common neurodegenerative diseases amyotrophic lateral sclerosis (ALS), Parkinson disease (PD) and Alzheimer disease (AD). Several interesting reports have compared pathological gene expression in different patient groups, disease stages and anatomical areas. In all three diseases, GEP has revealed dysregulation of genes related to neuroinflammation. In ALS and PD, gene expression related to RNA splicing and protein turnover is disrupted, and several studies in ALS support involvement of the cytoskeleton. GEP studies have implicated the ubiquitin-proteasome system in PD pathogenesis, and have provided evidence of mitochondrial dysfunction in PD and AD. Lastly, in AD, a possible role for dysregulation of intracellular signalling pathways, including calcium signalling, has been highlighted. This Review also provides a discussion of methodological considerations in microarray sample preparation and data analysis.

Scintigraphy using [111In-DTPA-d-Phe1]-pentetreotide or pentavalent technetium-99m-dimercaptosuccinic acid [99mTc(V)-DMSA] has been shown to localize well-differentiated and slowly growing neuroendocrine tumours, whereas increased fluorodeoxyglucose (FDG) uptake is associated with malignancy. The aim of this study was to compare the value of fluorine-18 FDG positron emission tomography (PET) with that of somatostatin receptor scintigraphy (SS-R) and dual-radionuclide scintigraphy [SS-R and 99mTc(V)-DMSA = DNS] in detecting malignant neuroendocrine tumours. Fifteen patients with metastasizing gastroenteropancreatic tumours (GEP tumours; n = 7), medullary thyroid carcinomas (MTCs; n = 8) and elevated tumour markers [GEP tumours: 5-hydroxyindoleacetic acid, insulin; MTCs: calcitonin, carcinoembryonic antigen (CEA)] were studied. Prior to PET, all patients with GEP tumours underwent SS-R. DNS was performed in all patients with MTC. Patients had been fasting for at least 12 h and normal glucose plasma levels were confirmed. Sixty minutes after intravenous administration of 18F-FDG (mean: 374 MBq) whole-body PET and regional scans were performed. In addition, the resected tissues were prepared for immunocytochemistry examination (cell cycle-associated Ki-67 antigen). In two patients with less-differentiated GEP tumours associated with high proliferative activity and increased FDG uptake, SS-R failed to detect any lesion. In comparison, in four patients with well-differentiated GEP tumours showing low proliferative activity, SS-R localized four primary tumours, 22 lymph node metastases and 18 malignant liver lesions, whereas 18F-FDG PET demonstrated normal distribution. In one patient with a metastasizing carcinoid (medium proliferative activity) SS-R localized multiple metastases, whereas PET demonstrated low FDG uptake in all known metastases. In patients with recurrent MTC and rapidly increasing CEA levels DNS detected only three lesions in two patients, whereas PET demonstrated one pulmonary, three osseous, 20 mediastinal, ten locoregional, and four liver metastases in seven patients. Twenty-nine malignant lesions were confirmed by follow-up and nine lymph node metastases could be surgically removed. In conclusion, PET imaging of gastroenteropancreatic tumours revealed increased glucose metabolism only in less-differentiated GEP tumours with high proliferative activity and metastasizing MTC associated with rapidly increasing CEA levels. Therefore, additional 18F-FDG PET should be performed only if SS-R or DNS is negative.

Somatostatin receptors (SSTRs) have been extensively mapped in human tumors by means of autoradiography, reverse-transcriptase polymerase chain reaction (RT-PCR), in situ hybridization (ISH) and immunohistochemistry (IHC). We analyzed the SSTR type 1-5 expression by means of RT-PCR and/or IHC in a series of 81 functioning and non-functioning gastroenteropancreatic (GEP) endocrine tumors and related normal tissues. Moreover, we compared the results with clinical, pathological and hormonal features. Forty-six cases (13 intestinal and 33 pancreatic) were studied for SSTR 1-5 expression using RT-PCR, IHC with antibodies to SSTR types 2, 3, 5 and ISH for SSTR2 mRNA. The vast majority of tumors expressed SSTR types 1, 2, 3 and 5, while SSTR4 was detected in a small minority. Due to the good correlation between RT-PCR and IHC data on SSTR types 2, 3, and 5, thirty-five additional GEP endocrine tumors were studied with IHC alone. Pancreatic insulinomas had an heterogeneous SSTR expression, while 100% of somatostatinomas expressed SSTR5 and 100% gastrinomas and glucagonomas expressed SSTR2. Pre-operative biopsy material showed an overlapping immunoreactivity with that of surgical specimens, suggesting that the SSTR status can be detected in the diagnostic work-up. It is concluded that SSTRs 1-5 are heterogeneously expressed in GEP endocrine tumors and that IHC is a reliable tool to detect SSTR types 2, 3 and 5 in surgical and biopsy specimens.

Diffuse large B-cell lymphoma (DLBCL) is the most commonly occurring form of non-Hodgkin lymphoma in the western world. Until the mid 1990s the incidence of DLBCL increased in both sexes, across racial categories, and across all age groups except the very young, the etiology of most cases remains unknown. DLBCL is associated with an aggressive natural history, but it can be cured with combination chemotherapy regimens like cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), which has been the mainstay of therapy for several decades. Remarkable progress has been made in understanding the biological heterogeneity of DLBCL and in improving survival for DLBCL patients with novel combinations of chemotherapy and immunotherapy. Gene expression profiling (GEP) has uncovered DLBCL subtypes that have distinct clinical behaviors and prognoses, and the addition of the monoclonal antibody, rituximab, to CHOP has markedly improved outcomes. Future approaches to DLBCL management will use molecular signatures identified through GEP to provide prognostic information and to isolate therapeutic targets that are being evaluated for DLBCL patients who relapse or those with high risk disease.

Bacteria have evolved several secretory pathways to release proteins into the extracellular medium. In Gram-negative bacteria, the exoproteins cross a cell envelope composed of two successive hydrophobic barriers, the cytoplasmic and outer membranes. In some cases, the protein is translocated in a single step across the cell envelope, directly from the cytoplasm to the extracellular medium. In other cases, outer membrane translocation involves an extension of the signal peptide-dependent pathway for translocation across the cytoplasmic membrane via the Sec machinery. By analogy with the so-called general export pathway (GEP), this latter route, including two separate steps across the inner and the outer membrane, was designated as the general secretory pathway (GSP) and is widely conserved among Gram-negative bacteria. In their great majority, exoproteins use the main terminal branch (MTB) of the GSP, namely the Xcp machinery in Pseudomonas aeruginosa, to reach the extracellular medium. In this review, we will use the P. aeruginosa Xcp system as a basis to discuss multiple aspects of the GSP mechanism, including machinery assembly, exoprotein recognition, energy requirement and pore formation for driving through the outer membrane.

Mutations in human cartilage oligomeric matrix protein (COMP) have been linked to the development of pseudoachondroplasia and multiple epiphyseal dysplasia; however, the functions of both wild-type and mutant COMP in the skeletogenesis remain unknown. In an effort to define the biological functions of COMP, a functional genetic screen based on the yeast two-hybrid system was performed. This led to the identification of granulin-epithelin precursor (GEP), an autocrine growth factor, as a COMP-associated partner. COMP directly binds to GEP both in vitro and in vivo, as revealed by in vitro pull down and co-immunoprecipitation assays. GEP selectively interacts with the epidermal growth factor repeat domain of COMP but not with the other three functional domains of COMP. The granulin A repeat unit of GEP is required and sufficient for association with COMP. COMP co-localizes with GEP predominantly in the pericellular matrix of transfected rat chondrosarcoma cell and primary human chondrocytes. Staining of musculoskeletal tissues of day 19 mouse embryo with antibodies to GEP is restricted to chondrocytes in the lower proliferative and upper hypertrophic zones. Overexpression of GEP stimulates the proliferation of chondrocytes, and this stimulation is enhanced by COMP. In addition, COMP appears to be required for GEP-mediated chondrocyte proliferation, since chondrocyte proliferation induced by GEP is dramatically inhibited by an anti-COMP antibody. These findings provide the first evidence linking the association of COMP and GEP and identifying a previously unrecognized growth factor (i.e. GEP) in cartilage.

Antiproliferative treatment of patients with metastatic endocrine gastroenteropancreatic tumours (GEP) is based mainly on chemotherapeutic protocols whereby drug toxicity is a major handicap. Octreotide is the first choice in the control of hormone mediated symptoms. From retrospective and a few prospective studies it has been suggested that octreotide exhibits antiproliferative properties. The prospective German Sandostatin multicentre phase II trial investigated the effects of 200 micrograms octreotide thrice daily for one year on tumour growth and endocrine abnormalities in 103 patients. Octreotide treatment was continued in those patients responding to the drug until tumour progression occurred. In 28 of those with tumour progression during 200 micrograms thrice daily octreotide dose was increased to 500 micrograms thrice daily. The study sample consisted of 52 patients with computed tomography confirmed tumour progression and 13 patients with stable disease before octreotide treatment, whereas no preobservation period was available in 38 patients. Nineteen patients (36.5%) with computed tomography confirmed tumour progression experienced stabilisation of tumour growth lasting for at least three months. Median duration of stable disease was 18 months. At month 12, stable disease continued in 12 patients, declined after 24 months to nine patients, and after 36 months to five patients. Tumour regression has not been seen in this or other subgroups. In the subgroup with stable disease before octreotide, stable disease continued in 53.8% of patients over 12 months. Increase of octreotide dose to 500 micrograms thrice daily did not influence progression seen during the lower dose with the exception of one patient in whom tumour progression changed to stable disease. No association of tumour size response and patients' characteristics could be detected. The results suggest that octreotide inhibits tumour growth in patients with metastasised endocrine GEP tumours. The antiproliferative effect is, at least in some patients, longlasting. Currently, octreotide can only be recommended as an antiproliferative drug if patients with clearly progressive disease show stabilisation after treatment for three to six months.

Thymidine kinase (TK) activity in WI-38 and MRC-5 human fibroblasts was analyzed by discontinuous polyacrylamide gel electrophoresis (disc-PAGE) and discontinuous glycerol gradient electrophoresis (disc-GEP) after subculture or human cytomegalovirus (HCMV) infection. Two peaks of TK activity with different relative fraction-of-migration (R(f)) values were resolved by disc-PAGE or disc-GEP in extracts from log-phase and infected cells. Growing WI-38 cells expressed a slowly migrating (R(f) = 0.14 PAGE, R(f) = 0.4 GEP) peak of TK activity, which was partially inhibited by 1.0 mM dCTP, but which retained little activity at pH 4.5. Growing MRC cells also displayed a slowly migrating peak (R(f) = 0.10 PAGE) with similar properties. Both cell types expressed a faster-migrating TK activity (R(f) = 0.45 PAGE, R(f) = 0.7 GEP) in the growing and resting state that was strongly inhibited by 1 mM dCTP but retained 50% activity at pH 4.5. When either cell type was infected with HCMV, there was a rapid and high-level stimulation of the slowly migrating form of TK and a slight stimulation of the faster-migrating form. Two strains of HCMV (AD169 and Town) failed to produce an electrophoretically distinct virus TK in either cell type after infection. TK enzymes were partially purified by disc-GEP from extracts of log-phase WI-38 or AD169-infected WI-38 cells. Characterization of these enzymes with respect to phosphate donor specificity, pH optima, thermostability, and salt inhibition showed the HCMV-stimulated TKs to be of cellular origin.

Synaptic proteins are synthesized in the cell body and transported down the axon by microtubule-dependent motors. We previously reported that KIF1Bbeta and KIF1A motors are essential for transporting synaptic vesicle precursors; however the mechanisms that regulate transport, as well as cargo recognition and control of cargo loading and unloading remain largely unknown. Here, we show that DENN/MADD (Rab3-GEP) is an essential part of the regulation mechanism through direct interaction with the stalk domain of KIF1Bbeta and KIF1A. We also show that DENN/MADD binds preferentially to GTP-Rab3 and acts as a Rab3 effector. These molecular interactions are fundamental as sequential genetic perturbations revealed that KIF1Bbeta and KIF1A are essential for the transport of DENN/MADD and Rab3, whereas DENN/MADD is essential for the transport of Rab3. GTP-Rab3 was more effectively transported than GDP-Rab3, suggesting that the nucleotide state of Rab3 regulates axonal transport of Rab3-carrying vesicles through preferential interaction with DENN/MADD.

Because the role of chemotherapy, interferon, or somatostatin analogs as antiproliferative agents is uncertain, currently few treatment options exist for patients with metastatic or inoperable gastroenteropancreatic neuroendocrine tumors (GEP-NET). Fifty-eight patients with somatostatin receptor-positive GEP-NET were treated in a phase I dose-escalating study with cumulative doses of 47 mCi to 886 mCi of the radiolabeled somatostatin analog [(90)Y-DOTA(0),Tyr(3)]-octreotide. At baseline, 47 patients had progressive disease, and 36 were symptomatic. The extent of disease was: 4 patients without liver metastases and 52 patients with liver metastases, including 16 patients with very advanced disease, qualified as "end-stage," and 2 end-stage patients without liver metastases. The objective responses were 5 partial response (PR), 7 minor response (MR), 29 stable disease (SD), and 17 PD. Overall, 33 patients (57%) experienced some improvement in their disease status, including conversion from PD into SD and improvement from SD into MR. Accordingly, 21 of 36 patients (58%) had improvement in Karnofsky performance score or symptoms. The median overall survival (OS) was 36.7 months (95% confidence interval [CI] 19.4-54.1 months). The median progression-free survival in 41 patients who had at least stable disease at the end of the treatment period was 29.3 months (95% CI 19.3-39.3 months). Patients who had SD at baseline had a significantly better OS than patients who had PD at baseline. The extent of disease at baseline also was a significant predictive factor for OS. The OS after therapy with [(90)Y-DOTA(0),Tyr(3)]-octreotide was significantly better than in a historic control group of 32 comparable patients with GEP-NET who had been treated with another radiolabeled somatostatin analog, [(111)In-DTPA(0)]-octreotide (median OS 12.0 months, 95% CI 6.2-17.8 months). The difference in OS for both therapies remained highly significant in a multivariate Cox proportional hazard model including progression status and extent of disease at baseline as covariates. Although the objective response after therapy with [(90)Y-DOTA(0),Tyr(3)]-octreotide by standard criteria seems modest, the significantly longer OS compared with historic controls is most encouraging.

There is a strong need to better predict the survival of patients with newly diagnosed multiple myeloma (MM). As gene expression profiles (GEPs) reflect the biology of MM in individual patients, we built a prognostic signature based on GEPs. GEPs obtained from newly diagnosed MM patients included in the HOVON65/GMMG-HD4 trial (n=290) were used as training data. Using this set, a prognostic signature of 92 genes (EMC-92-gene signature) was generated by supervised principal component analysis combined with simulated annealing. Performance of the EMC-92-gene signature was confirmed in independent validation sets of newly diagnosed (total therapy (TT)2, n=351; TT3, n=142; MRC-IX, n=247) and relapsed patients (APEX, n=264). In all the sets, patients defined as high-risk by the EMC-92-gene signature show a clearly reduced overall survival (OS) with a hazard ratio (HR) of 3.40 (95% confidence interval (CI): 2.19-5.29) for the TT2 study, 5.23 (95% CI: 2.46-11.13) for the TT3 study, 2.38 (95% CI: 1.65-3.43) for the MRC-IX study and 3.01 (95% CI: 2.06-4.39) for the APEX study (P<0.0001 in all studies). In multivariate analyses this signature was proven to be independent of the currently used prognostic factors. The EMC-92-gene signature is better or comparable to previously published signatures. This signature contributes to risk assessment in clinical trials and could provide a tool for treatment choices in high-risk MM patients.

The new WHO classification of gastroenteropancreatic (GEP) neuroendocrine tumors (NET) implies that G3 neoplasms with mitotic index >20 and/or Ki67 index >20% are neuroendocrine carcinomas (NEC), described as poorly differentiated, small or large cell types, by analogy with lung NEC. To characterize the subgroup of non-small-cell-type GEP and thoracic NET with mitotic index >20 and/or Ki67 >20% according to their pathological features, response to cisplatin and overall survival (OS). We reviewed pathological and clinical presentation of G3 non-small-cell-type NET referred to our institution for 5 years. Data from 166 patients with metastatic thoracic and GEP-NET were collected. Twenty-eight patients (17%) fulfill the inclusion criteria. Tumors were classified as well-differentiated NET (G3-WDNET) in 42.8% of cases and poorly differentiated, large-cell NEC (G3-LCNEC) in 57.2% of cases. Plasma chromogranin A or neuron-specific enolase were elevated in 42 and 25% respectively of G3-WDNET and 31 and 50% of G3-LCNEC. Somatostatin receptor scintigraphy was positive in 88 and 50% of G3-WDNET or G3-LCNEC respectively. Complete or partial response to cisplatin was observed in 31% of cases, all classified as G3-LCNEC. The median OS was 41 months for G3-WDNET but 17 months for G3-LCNEC (P=0.34). Short survival was observed in 25% of G3-WDNET but 62.5% of G3-LCNEC patients (P=0.049). G3 ENETS GEP and thoracic neuroendocrine neoplasms (NEN) could constitute a heterogeneous subgroup of NEN as regards diagnosis, prognosis, and treatment. If confirmed, future classifications may consider splitting them into two groups according to their morphological differentiation.

Gene expression profiling (GEP) on frozen tissues has identified genes predicting outcome in patients with diffuse large B-cell lymphoma (DLBCL). Confirmation of results in current patients is limited by availability of frozen samples and addition of monoclonal antibodies to treatment regimens. We used a quantitative nuclease protection assay (qNPA) to analyze formalin-fixed, paraffin-embedded tissue blocks for 36 previously identified genes (N = 209, 93 chemotherapy; 116 rituximab + chemotherapy). By qNPA, 208 cases were successfully analyzed (99.5%). In addition, 15 of 36 and 11 of 36 genes, representing each functional group previously identified by GEP, were associated with survival (P < .05) in the 2 treatment groups, respectively. In addition, 30 of 36 hazard ratios of death trended in the same direction versus the original studies. Multivariate and variable cut-off point analysis identified low levels of HLA-DRB (< 20%) and high levels of MYC >> 80%) as independent indicators of survival, together distinguishing cases with the worst prognosis. Our results solve a clinical research problem by demonstrating that prognostic genes can be meaningfully quantified using qNPA technology on formalin-fixed, paraffin-embedded tissues; previous GEP findings in DLBCL are relevant with current treatments; and 2 genes, representing immune escape and proliferation, are the common features of the most aggressive DLBCL.

The gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are composed of cells with a neuroendocrine phenotype. Well-differentiated tumors, well-differentiated carcinomas, poorly differentiated carcinomas, functioning tumors (with a hormonal syndrome), and nonfunctioning tumors are identified. To predict their clinical behavior, these neuroendocrine tumors are classified on the basis of their clinicopathological features, including size, local invasion, angioinvasion, proliferative activity, histological differentiation, and metastases, into neoplasms with benign, uncertain, low-grade malignant and high-grade malignant behavior. In addition, a tumor/nodes/metastases classification and a grading system are presented. In the light of these criteria, the various GEP-NET entities are reviewed.

Activation of ADP-ribosylation factors (ARFs), approximately 20-kDa guanine nucleotide-binding proteins that play an important role in intracellular vesicular trafficking, depends on guanine nucleotide-exchange proteins (GEPs), which accelerate replacement of bound GDP with GTP. Two major families of ARF GEPs are known: approximately 200-kDa molecules that are inhibited by brefeldin A (BFA), a fungal metabolite that blocks protein secretion and causes apparent disintegration of Golgi structure, and approximately 50-kDa GEPs that are insensitive to BFA. We describe here two human brain cDNAs that encode BFA-inhibited GEPs. One is a approximately 209-kDa protein 99.5% identical in deduced amino acid sequence (1, 849 residues) to a BFA-inhibited ARF GEP (p200) from bovine brain. The other smaller protein, which is approximately 74% identical (1, 785 amino acids), represents a previously unknown gene. We propose that the former, p200, be named BIG1 for (brefeldin A-inhibited GEPGEPs are known, these new clones for the approximately 200-kDa BIG1 and BIG2 should facilitate characterization of this rather different family of proteins as well as the elucidation of mechanisms of regulation of BFA-sensitive ARF function in Golgi transport.

Brefeldin A (BFA) inhibited the exchange of ADP ribosylation factor (ARF)-bound GDP for GTP by a Golgi-associated guanine nucleotide-exchange protein (GEP) [Helms, J.B. & Rothman, J.E. (1992) Nature (London) 360, 352-354; Donaldson, J.G., Finazzi, D. & Klausner, R.D. (1992) Nature (London) 360, 350-352]. Cytosolic ARF GEP was also inhibited by BFA, but after purification from bovine brain and rat spleen, it was no longer BFA-sensitive [Tsai, S.-C., Adamik, R., Moss, J. & Vaughan, M. (1996) Proc. Natl. Acad. Sci. USA 93, 305-309]. We describe here purification from bovine brain cytosol of a BFA-inhibited GEP. After chromatography on DEAE-Sephacel, hydroxylapatite, and Mono Q and precipitation at pH 5.8, GEP was eluted from Superose 6 as a large molecular weight complex at the position of thyroglobulin (approximately 670 kDa). After SDS/PAGE of samples from column fractions, silver-stained protein bands of approximately 190 and 200 kDa correlated with activity. BFA-inhibited GEP activity of the 200-kDa protein was demonstrated following electroelution from the gel and renaturation by dialysis. Four tryptic peptides from the 200-kDa protein had amino acid sequences that were 47% identical to sequences in Sec7 from Saccharomyces cerevisiae (total of 51 amino acids), consistent with the view that the BFA-sensitive 200-kDa protein may be a mammalian counterpart of Sec7 that plays a similar role in cellular vesicular transport and Sec7 may be a GEP for one or more yeast ARFs.

The incidence and prevalence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) have increased in the past 20 years. GEP-NETs are heterogeneous tumors, in terms of clinical and biological features, that originate from the pancreas or the intestinal tract. Some GEP-NETs grow very slowly, some grow rapidly and do not cause symptoms, and others cause hormone hypersecretion and associated symptoms. Most GEP-NETs overexpress receptors for somatostatins. Somatostatins inhibit the release of many hormones and other secretory proteins; their effects are mediated by G protein-coupled receptors that are expressed in a tissue-specific manner. Most GEP-NETs overexpress the somatostatin receptor SSTR2; somatostatin analogues are the best therapeutic option for functional neuroendocrine tumors because they reduce hormone-related symptoms and also have antitumor effects. Long-acting formulations of somatostatin analogues stabilize tumor growth over long periods. The development of radioactive analogues for imaging and peptide receptor radiotherapy has improved the management of GEP-NETs. Peptide receptor radiotherapy has significant antitumor effects, increasing overall survival times of patients with tumors that express a high density of SSTRs, particularly SSTR2 and SSTR5. The multi-receptor somatostatin analogue SOM230 (pasireotide) and chimeric molecules that bind SSTR2 and the dopamine receptor D2 are also being developed to treat patients with GEP-NETs. Combinations of radioactive labeled and unlabeled somatostatin analogues and therapeutics that inhibit other signaling pathways, such as mammalian target of rapamycin (mTOR) and vascular endothelial growth factor, might be the most effective therapeutics for GEP-NETs.

OBJECTIVE

Neuroendocrine tumors of the gynecologic tract are rare, and pose a significant clinical challenge because of the tumor heterogeneity and lack of standardized guidelines for treatment. This manuscript summarizes the available literature concerning these tumors in an effort to provide the clinician a framework from which to guide patient management.

METHODS

MEDLINE was searched for all research articles published in English between January 1, 1966 and March 1, 2011 in which the studied population included women diagnosed with neuroendocrine tumors of the gynecologic tract. Although preference was given to prospective studies, studies were not limited by design or by numbers of subjects given the limited availability of reports.

RESULTS

Most, but not all, neuroendocrine tumors of the gynecologic tract have an aggressive clinical course and those of the cervix histologically and clinically share similarities with small cell lung cancer. Cumulative data supports a multi-modality therapeutic strategy. A proposed management algorithm for neuroendocrine carcinomas of the cervix is outlined. For less frequent disease sites including the adnexa, uterus, vagina and vulva, as well as well differentiated carcinoid tumors, surgical resection is appropriate in selected cases. Etoposide/platinum based chemotherapy is used for neuroendocrine carcinomas but not for well differentiated carcinoid tumors. Well differentiated carcinoid and atypical carcinoid tumors should be managed similar to gastroenteropancreatic NETs (GEP-NETs).

CONCLUSIONS

Most neuroendocrine tumors of the gynecologic tract require a multi-modality therapeutic approach, determined by extent of disease and primary organ of involvement. Pathologic diagnosis is critical to guide therapy.