OBJECTIVE

Given the likely proliferation of targeted testing and treatment strategies for cancer, a better understanding of the utilization patterns of human epidermal growth factor receptor 2 (HER2) testing and trastuzumab and newer gene expression profiling (GEP) for risk stratification and chemotherapy decision making are important.

METHODS

Cross-sectional.

METHODS

We performed a medical record review of women age 35 to 65 years diagnosed between 2006 and 2007 with invasive localized breast cancer, identified using claims from a large national health plan (N = 775).

RESULTS

Almost all women received HER2 testing (96.9%), and 24.9% of women with an accepted indication received GEP. Unexplained socioeconomic differences in GEP use were apparent after adjusting for age and clinical characteristics; specifically, GEP use increased with income. For example, those in the lowest income category (< $40,000) were less likely than those with an income of $125,000 or more to receive GEP (odds ratio, 0.34; 95% CI, 0.16 to 0.73). A majority of women (57.7%) with HER2-positive disease received trastuzumab; among these women, differences in age and clinical characteristics were not apparent, although surprisingly, those in the lowest income category were more likely than those in the high-income category to receive trastuzumab (P = .02). Among women who did not have a positive HER2 test, 3.9% still received trastuzumab. Receipt of adjuvant chemotherapy increased as GEP score indicated greater risk of recurrence.

CONCLUSIONS

Identifying and eliminating unnecessary variation in the use of these expensive tests and treatments should be part of quality improvement and efficiency programs.

Activins and inhibins, which belong to the TGF beta family, are composed of different combinations of alpha-, betaA-, and betaB-subunits, resulting in inhibin A (alphabetaA), inhibin B (alphabetaB), activin A (betaAbetaA), activin B (betaBbetaB), and activin AB (betaAbetaB). They regulate several cell functions, acting as paracrine/autocrine factors. Their actions, which depend on binding to specific receptors, are also modulated by follistatin. Gastroenteropancreatic (GEP) endocrine cells and endocrine tumors (ETs) produce several growth factors, but it is not well known whether they express follistatin and the various inhibin/activin subunits. We studied their expression in 65 GEP ETs using immunohistochemistry (IHC) and in situ hybridization (ISH). The alpha-subunit and follistatin were not identified in normal GEP endocrine cells and were poorly expressed in ETs. A betaA-subunit immunoreactivity (IR) was detected in A-, G-, EC-, and GIP-cells, while betaB-chain IR was present only in D-cells. The mRNAs encoding for these molecules were poorly expressed in normal tissues. BetaA- and betaB-subunits were identified in several ETs by both IHC and ISH: betaA-subunit mainly in G-cell and A-cell ETs, and betaB-subunit in D-cell, A-cell, and EC-cell ETs. Our results demonstrate a differential expression of activin/inhibin subunits among different types of GEP endocrine cells and related tumors, suggesting a role in modulation of biological functions of these normal and neoplastic endocrine cells.

Most models of photosynthetic activity assume that temperature is the dominant control over physiological processes. Recent studies have found, however, that photoperiod is a better descriptor than temperature of the seasonal variability of photosynthetic physiology at the leaf scale. Incorporating photoperiodic control into global models consequently improves their representation of the seasonality and magnitude of atmospheric CO2 concentration. The role of photoperiod versus that of temperature in controlling the seasonal variability of photosynthetic function at the canopy scale remains unexplored. We quantified the seasonal variability of ecosystem-level light response curves using nearly 400 site years of eddy covariance data from over eighty Free Fair-Use sites in the FLUXNET database. Model parameters describing maximum canopy CO2 uptake and the initial slope of the light response curve peaked after peak temperature in about 2/3 of site years examined, emphasizing the important role of temperature in controlling seasonal photosynthetic function. Akaike's Information Criterion analyses indicated that photoperiod should be included in models of seasonal parameter variability in over 90% of the site years investigated here, demonstrating that photoperiod also plays an important role in controlling seasonal photosynthetic function. We also performed a Granger causality analysis on both gross ecosystem productivity (GEP) and GEP normalized by photosynthetic photon flux density (GEP n ). While photoperiod Granger-caused GEP and GEP n in 99 and 92% of all site years, respectively, air temperature Granger-caused GEP in a mere 32% of site years but Granger-caused GEP n in 81% of all site years. Results demonstrate that incorporating photoperiod may be a logical step toward improving models of ecosystem carbon uptake, but not at the expense of including enzyme kinetic-based temperature constraints on canopy-scale photosynthesis.

The differentiation of lymphoid cells is tightly regulated by transcription factors at various stages during their development. During the maturation processes, different genomic alterations or aberrations such as chromosomal translocation, mutation and deletions may occur that can eventually result in distinct biological and clinical tumors. The different differentiation stages create heterogeneity in lymphoid malignancies, which can complicate the diagnosis. The initial diagnostic scheme for lymphoid diseases was coined by Rappaport followed by Revised European and American Classification of Lymphoid Neoplasms (REAL) and World Health Organization (WHO) classifications. These classification methods were based on histological, immunophenotypic and cytogenetic markers and widely accepted by pathologists and oncologists worldwide. During last several decades, great progress has been made in understanding the etiology, pathogenesis and molecular biology of malignant lymphoma. However, detailed knowledge in the molecular mechanism of lymphomagenesis is largely unknown. New therapeutic protocols based on the new classification have been on clinical trials, but with little success. Therefore, it is imperative to understand the basic biology of the tumor at molecular level. One important approach will be to measure the activity of the tumor genome and this can partly be achieved by the measurement of whole cellular mRNA. One of the key technologies to perform a high-throughput analysis is DNA microarray technology. The genome-wide transcriptional measurement, also called gene expression profile (GEP) can accurately define the biological phenotype of the tumor. In this review, important discoveries made by genome-wide GEP in understanding the biology of lymphoma and additionally the diagnostic and prognostic value of microarrays are discussed.

Recently, a novel WHO-classification has been introduced that divided gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) according to their proliferation index into G1- or G2-neuroendocrine tumors (NET) and poorly differentiated small-cell or large-cell G3-neuroendocrine carcinomas (NEC). Our knowledge on primary NECs of the GEP-system is limited due to the rarity of these tumors and chemotherapeutic concepts of highly aggressive NEC do not provide convincing results. The aim of this study was to establish a reliable cell line model for NEC that could be helpful in identifying novel druggable molecular targets. Cell lines were established from liver (NEC-DUE1) or lymph node metastases (NEC-DUE2) from large cell NECs of the gastroesophageal junction and the large intestine, respectively. Morphological characteristics and expression of neuroendocrine markers were extensively analyzed. Chromosomal aberrations were mapped by array comparative genomic hybridization and DNA profiling was analyzed by DNA fingerprinting. In vitro and in vivo tumorigenicity was evaluated and the sensitivity against chemotherapeutic agents assessed. Both cell lines exhibited typical morphological and molecular features of large cell NEC. In vitro and in vivo experiments demonstrated that both cell lines retained their malignant properties. Whereas NEC-DUE1 and -DUE2 were resistant to chemotherapeutic drugs such as cisplatin, etoposide and oxaliplatin, a high sensitivity to 5-fluorouracil was observed for the NEC-DUE1 cell line. Taken together, we established and characterized the first GEP large-cell NEC cell lines that might serve as a helpful tool not only to understand the biology of these tumors, but also to establish novel targeted therapies in a preclinical setup.

OBJECTIVE

Primary lung adenocarcinoma remains a deadly disease. Gene-expression phenotypes (GEPs) in adenocarcinoma have potential to provide clinically relevant disease stratification for improved prognosis and treatment prediction, given appropriate clinical and methodologic validation.

METHODS

2,395 transcriptional adenocarcinoma profiles were assembled from 17 public cohorts and classified by a nearest centroid GEP classifier into three subtypes: terminal respiratory unit (TRU), proximal-proliferative, and proximal-inflammatory, and additionally scored by five transcriptional metagenes representing different biologic processes, including proliferation. Prognostic- and chemotherapy-predictive associations of the subtypes were analyzed by univariate and multivariate analysis using overall survival or distant metastasis-free survival as endpoints.

RESULTS

Overall, GEPs were associated with patient outcome in both univariate and multivariate analyses, although not in all individual cohorts. The prognostically relevant division was between TRU- and non-TRU-classified cases, with expression of proliferation-associated genes as a key prognostic component. In contrast, GEP classification was not predictive of adjuvant chemotherapy response. GEP classification showed stability to random perturbations of genes or samples and alterations to classification procedures (typically <10% of cases/cohort switching subtype). High classification variability (>20% of cases switching subtype) was observed when removing larger or entire fractions of a single subtype, due to gene-centering shifts not addressable by the classifier.

CONCLUSIONS

In a large-scale evaluation, we show that GEPs add prognostic value to standard clinicopathologic variables in lung adenocarcinoma. Subject to classifier refinement and confirmation in prospective cohorts, GEPs have potential to affect the prognostication of adenocarcinoma patients through a molecularly driven disease stratification.

OBJECTIVE

To investigate the clinicopathological features, survival and prognostic factors for gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) in a Chinese population.

METHODS

We investigated 154 consecutive patients (88 males, 66 females; median age 56 years, age range 9-86 years) diagnosed with GEP-NENs between 2001 and 2013 at The Affiliated Hospital of Qingdao University. Demographic, clinical and pathological variables and survival data were retrieved.

RESULTS

The pancreas was the most common site of involvement (63/154, 40.9%). Tumor size varied from 0.3 to 16.0 cm (median, 1.2 cm). The patients were followed up for a median period of 22 months (range, 1-157 months). The estimated 3- and 5-year overall survival (OS) rates for all patients were 84.0% and 81.9%, respectively. Multivariate analysis showed that larger tumor size, lymphatic metastases and distant metastases were significant predictors for poor survival outcome.

CONCLUSIONS

Our data provide further information on the clinicopathological features of GEP-NENs in China. Additionally, we identified tumor size, lymphatic metastases and distant metastases as independent prognostic factors for long-term survival.

OBJECTIVE

Ghrelin, a gut-brain peptide involved in the control of energy homeostasis, affects antero-pituitary and gastro-entero-pancreatic (GEP) hormone secretion in healthy subjects. We aimed to verify whether such hormonal responses are retained in acromegaly, a disease characterized by high GH, subnormal ghrelin and abnormal GEP hormone levels.

METHODS

The effect of ghrelin (3.3 microg/kg given after overnight fasting as an i.v. bolus) on GH, prolactin (PRL), adrenocorticotropin (ACTH), cortisol, insulin, glucose, total somatostatin (SS) and pancreatic polypeptide (PP) circulating levels were evaluated in seven non-diabetic patients with newly diagnosed acromegaly and in nine healthy controls.

RESULTS

Ghrelin elicited a prompt, marked increase of serum GH and PRL levels in all normal (from 1.6+/-0.6 to 52.9+/-7.8 and from 9.7+/-0.8 to 24.2+/-4.8 microg/l (means+/-S.E.M.), respectively) and acromegalic subjects (from 11.2+/-4.9 to 91.6+/-21.0 and from 42.9+/-26.1 to 113.8+/-79.0 microg/l, respectively). Both plasma ACTH and serum cortisol levels rose significantly in the controls, whereas the cortisol response was blunted in the acromegalic patients. Glucose levels rose earlier and insulin levels fell later in all subjects, with a significantly greater net insulin decrease in acromegalic than in healthy subjects (-80+/-21 vs -17+/-4 pmol/l, P<0.01). A prompt PP rise and a biphasic SS response occurred in all controls, whereas in the acromegalic group the PP response (from 26.1+/-5.0 to 92.2+/-39.0 pmol/l) and the SS response (from 11.9+/-3.0 to 19.7+/-4.0 ng/l) were quite variable.

CONCLUSIONS

Ghrelin affects both pituitary and GEP hormones in acromegalic patients as in normal subjects. These findings suggest that ghrelin actions on the energy balance are mediated by complex interactive endocrine loops that involve also the gut and pancreas.

Previous studies have demonstrated that the 5-hydroxytryptamine1A (5-HT1A) agonist buspirone stimulated rat prolactin (PRL) secretion. Administration of the 5-HT1A agonists gepirone (GEP) or ipsapirone (IPS) s.c. in doses from 1 to 10 mg/kg had no effect on PRL secretion in male rats. However, pretreatment with GEP (10 mg/kg) or IPS (10 mg/kg) significantly attenuated the increase in serum PRL concentration elicited by the 5-HT agonists 5-methoxy-N,N-dimethyltryptamine or 6-chloro-2-(1-piperazinyl)-pyrazine (MK-212). To determine whether the inhibitory effect of GEP or IPS was related to a serotonergic mechanism or a more general inhibitory effect on PRL secretion, the ability of GEP and IPS to inhibit the haloperidol- or alpha-methyl-p-tyrosine-induced increase in PRL secretion was studied. GEP (1, 3 and 10 mg/kg) and IPS (10 mg/kg) inhibited the increase in PRL secretion produced by either haloperidol (0.25 mg/kg) or alpha-methyl-p-tyrosine (75 mg/kg). Furthermore, GEP produced a concentration-dependent inhibition of PRL secretion from anterior pituitary tissue incubated in vitro. The inhibitory effect of GEP was comparable to that of dopamine in this system. Moreover, haloperidol blocked completely the GEP-mediated suppression of PRL secretion in this preparation. These data suggest agonist properties of both GEP and IPS at D2 dopamine receptors. In light of other evidence that GEP has D2 antagonist effects in vivo, we hypothesize that GEP and perhaps IPS are partial dopamine agonists which may contribute to their antianxiety and/or antidepressant properties.

The selective group-III metabotropic glutamate receptor agonist, L-serine-O-phosphate (L-SOP), when injected bilaterally into the inferior colliculus of the sound sensitive genetically epilepsy-prone (GEP) rats produces a short proconvulsant excitation followed by a long phase of protection against sound-induced seizures lasting for 2-4 days. We have studied this prolonged suppression of audiogenic seizures using pharmacological and molecular biological approaches including semiquantitative RT-PCR and western blotting. The intracerebroventricular injection of the protein synthesis inhibitor cycloheximide (120 microg) 30 min beforehand significantly reduces the proconvulsant seizure activity and the prolonged anticonvulsant effect of intracollicular L-SOP (500 nmol/side). The sensitive semiquantitative RT-PCR revealed a significant up-regulation in mGlu(4) and mGlu(7) mRNA levels in the inferior colliculus at 2 days (maximum suppression of audiogenic seizures) after intracollicular L-SOP injection compared with the non-injected, 2-day post-vehicle treated and 7-day (return to expressing audiogenic seizures) post-drug or vehicle-treated groups. No significant changes were observed in mGlu(6) or mGlu(8) mRNA expression levels in drug-treated compared with control groups. Examination of mGlu(4a) and mGlu(7a) protein levels using western blotting showed a significant increase in mGlu(7a) but no significant change in mGlu(4a) protein levels 2 days after L-SOP treatment compared with the control groups (non-injected and 2-day vehicle-injected group). These results suggest that up-regulation of mGlu(7) receptors is involved in the prolonged anticonvulsant effect of L-SOP against sound-induced seizures in GEP rats. The potential use of mGlu(7) agonists as novel anti-epileptic agents merits investigation.

BACKGROUND

Epigenetic remodelling of cancer cells is an attractive therapeutic strategy and distinct DNA hypomethylating agents (DHA) are being actively evaluated in patients with hemopoietic or solid tumours. However, no studies have investigated the modulation of gene expression profiles (GEP) induced by DHA in transformed and benign tissues. Such information is mandatory to clarify the fine molecular mechanism(s) underlying the clinical efficacy of DHA, to identify appropriate therapeutic combinations, and to address safety issues related to their demethylating potential in normal tissues. Thus, utilising a syngeneic mouse model, we investigated the remodelling of GEP of neoplastic and normal tissues induced by systemic administration of DHA.

METHODS

The murine mammary carcinoma cells TS/A were injected s.c. into female BALB/c mice that were treated i.p. with four cycles of the DHA 5-aza-2'-deoxycytidine (5-AZA-CdR) at a fractioned daily dose of 0.75 mg kg(-1) (q8 h × 3 days, every week). Whole mouse transcriptomes were analysed by microarrays in neoplastic and normal tissues from control and treated mice. Results were processed by bioinformatic analyses.

RESULTS

In all, 332 genes were significantly (P ≤ 0.05; FC ≥ 4) modulated (294 up and 38 downregulated) in neoplastic tissues from 5-AZA-CdR-treated mice compared with controls. In decreasing order of magnitude, changes in GEP significantly (P ≤ 0.05) affected immunologic, transport, signal transduction, spermatogenesis, and G-protein-coupled receptor protein signalling pathways. Epigenetic remodelling was essentially restricted to tumour tissues, leaving substantially unaltered normal ones.

CONCLUSIONS

The ability of 5-AZA-CdR to selectively target tumour GEP and its major impact on immune-related genes, strongly support the clinical use of DHA alone or combined with immunotherapeutic agents.

Autonomic nerves and endocrine cells of both the gastrointestinal tract and the pancreatic islets participate in the control of several processes related to the digestion and metabolism of nutrients. While it was once thought that they acted separately to regulate these processes, it is now appreciated that numerous interactions exist between the functions of autonomic nerves and GEP endocrine cells. Recent studies show that autonomic signals play a role in the secretory activity of various GEP cells, thus providing a mechanism by which the central nervous system can integrate digestive and metabolic functions. It also has been shown that nerves and endocrine cells frequently share certain common peptides and/or amines. Therefore, in functional terms, it is often difficult to determine whether a specific peptide or amine should be considered a neurotransmitter or a hormone. Within the next few years, one can reasonably expect that new techniques and methods of investigation will clarify the roles of putative chemical messengers such as the peptides found within autonomic nerves and the amines found within endocrine cells. It also seems likely that future studies will demonstrate that the specific chemical messenger and the mechanism by which it reaches its target cells are far more important factors in the understanding of gastrointestinal and endocrine pancreatic function, than whether or not these signals are neural or endocrine in origin.

Neuroendocrine neoplasms (NENs) consist of a large heterogeneous group of epithelial tumors with neuroendocrine differentiation, as proved by immune reactivity for neuroendocrine markers. From the very first studies of vascular endothelial growth factor (VEGF) pathway, VEGF has been considered an important prognostic marker in NENs. Consequently, a number of preclinical experiences and clinical trials have examined the efficacy of VEGF-targeted therapeutics in NENs. Bevacizumab and sorafenib were clinically tested in NENs and they showed modest activity, while on the other hand, they present significant toxicity problems. More interesting in gastroenteropancreatic (GEP)-NENs seems to be the demonstrated efficacy of sunitinib. Preclinical as well as clinical sunitinib data in this regard provide a new hope in that direction. The use of other novel VEGF-targeted agents like aflibercept as well as VEGFR-TKI is being investigated in a number of phase II studies; the results of which are greatly awaited. Additionally, the use of potential biomarkers to select patients for VEGF-targeted therapy may be considered for further clinical evaluation. Thus, this article reviews the basic science as well as clinical data of VEGF signaling in advanced NENs with special emphasis on the different VEGF-targeting agents tested previously in this disease and the future prospective in that field.

ADP-ribosylation factors or ARFs are 20-kDa guanine nucleotide-binding proteins, initially identified as stimulators of cholera toxin-catalyzed ADP-ribosylation of Gs alpha. We now know that ARFs play a critical role in many vesicular trafficking events and ARF activation of a membrane-associated phospholipase D (PLD) has been recognized. ARF is active and associates with membranes when GTP is bound. The active state is terminated by hydrolysis of bound GTP, producing inactive ARF-GDP. The nucleotide effect on ARF association with membranes is related to alteration in orientation of the N-terminal myristoyl moiety that is important for ARF function. Cycling of ARF between active and inactive states involves guanine nucleotide-exchange proteins (GEPs) that accelerate replacement of bound GDP with GTP and GTPase-activating proteins (GAPS) that are responsible for ARF inactivation. Six mammalian ARFs have been identified by cDNA cloning. Class I ARFs 1 and 3 have been studied most extensively. Their activation (GTP binding) is catalyzed by a GEP now purified from spleen cytosol. In crude preparations, GEP was inhibited by brefeldin A (BFA), which in cells causes apparent disintegration of Golgi. Demonstration that the approximately 60 kDa purified GEP was not inhibited by BFA means that contrary to earlier belief, there must be another protein to mediate BFA inhibition. GEP activity was greatly enhanced by phosphatidyl serine. The purified GEP, equally active with ARFs 1 and 3, was inactive with ARFs 5 and 6 (Classes II and III); myristoylated ARFs were better substrates than were their non-myristoylated counterparts. ARF GAP purified from bovine spleen cytosol in our laboratory had much broader substrate specificity than the GEP. It used both ARFs 5 and 6 at least as well as ARFs 1 and 3; myristoylation was without effect. It also accelerated GTP hydrolysis by certain ARF mutants and an ARF-like protein (ARL1) that does not have ARF activity. The purified GAP also differed from the GEP in its rather specific requirement for phosphatidylinositol bisphosphate. This was also observed with a seemingly different ARF GAP that was purified and subsequently cloned in Cassel's laboratory. Activation and inactivation of ARFs present many potential sites for physiological regulation and, therefore, for pathological disruption of ARF function.

The development of high throughput technologies based on the knowledge of the human genome has opened the possibility to search for global genomic alterations in tumors responsible for their development and progression that may have important clinical implications. One of the major applications of this genomic knowledge has been the design of different types of microarray platforms for the analysis of DNA alterations and gene expression profiling (GEP). The main contributions of the DNA studies in lymphoid neoplasms include the definition of relatively characteristic genomic profiles for specific disease entities, the demonstration of common chromosomal alterations across entities, the identification of genes and pathways targeted by the altered chromosomal regions, and the identification of chromosomal alterations with prognostic implications. RNA GEP studies in these tumors have enhanced the molecular characterization of known entities and facilitated the recognition of new subtypes and categories of lymphoid neoplasms, the identification of new biomarkers and prognostic models, and the detection of oncogenic pathways with potential implications for targeted therapies. The recent development of the next generation sequencing (NGS) technologies and its application in lymphoid neoplasms already have provided an initial view of the complex landscape of somatic mutations in these tumors and some findings with important functional and clinical implications. This review addresses the major contributions and limitations of the microarray technologies in the understanding of lymphoid neoplasms and discusses how this knowledge may be transferred into the clinics. The initial results of the NGS studies are also presented.

BACKGROUND

Liver metastases are a strong prognostic indicator in patients with gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs). Therapeutic options for metastatic NETs are expanding and not mutually exclusive.

OBJECTIVE

This paper reviews the literature relating to multidisciplinary approach towards GEP-NET metastases, to highlight advances in knowledge regarding these tumors, and to understand the interdisciplinary management of individual patients.

METHODS

A PubMed search was performed for English-language publications from 1995 through 2012. Reference lists from studies selected were manually searched to identify further relevant reports. Manuscripts comparing different therapeutic options and advances for GEP-NET-related liver metastases were selected.

RESULTS

There is considerable controversy regarding the optimal management of GEP-NET metastases. Although radical surgery still remains the gold standard, a variety of other therapeutic options are available for metastatic GEP-NETs, including loco-regional chemotherapy/radiotherapy, radioembolization, systemic peptide receptor radionuclide therapy, biotherapy, and chemotherapy. In selected patients, liver transplantation should also be considered. Systemic somatostatin analogues and/or interferon show anti-proliferative effects, representing an appropriate first-line treatment for most patients. In advanced metastatic NETs, recent options include targeted therapies (i.e., everolimus and sunitinib).

CONCLUSIONS

It is evident that multidisciplinary care and multimodality treatments remain the cornerstone of management of NET patients. Since NETs often show a more indolent behavior compared to other malignancies, physicians should aim to preserve a satisfactory quality of life for the patient by personalizing the therapeutic approach according to the tumor's features and prognostic factors.

OBJECTIVE

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) represent a heterogeneous disease group originating from the neuroendocrine cells. Identification of prognostic markers, related to neuroendocrine tissue-selective tumorigenesis, is necessary to find therapeutic targets.

METHODS

A total of 327 patients with GEP-NETs were included in this study; there were 49 gastric, 29 duodenal, 49 pancreatic, 12 hepatobiliary, 33 appendiceal, 5 proximal colon, and 150 distal colon cases. We performed immunostaining with the tissue microarray method for menin, p27, and p18.

RESULTS

We observed negative staining for menin, p27, and p18 in 34%, 21%, and 56% of GEP-NETs, respectively. The loss of p27, but not menin, was positively correlated with the grade of Ki-67. Menin-/p27-, menin-/p27+, menin+/p27-, and menin+/p27+ phenotype groups included 13%, 22%, 8%, and 57% of patients, respectively. A dichotomized comparison showed that menin- or p27- tumors were significantly associated with foregut and midgut localizations, high World Health Organization (WHO) grade, lymph node metastasis, and more advanced stage as compared to menin+/p27+ patients. Kaplan-Meier analysis for the overall survival showed that p27 loss was significantly associated with decreased survival. Multivariate analysis showed that p27 loss is an independent factor for poor overall survival.

CONCLUSIONS

Our results revealed that the loss of p27 is associated with poor prognosis and the menin-p27 pathway is important in the tumorigenesis of GEP-NETs.

Cluster analysis is one of the crucial steps in gene expression pattern (GEP) analysis. It leads to the discovery or identification of temporal patterns and coexpressed genes. GEP analysis involves highly dimensional multivariate data which demand appropriate tools. A good alternative for grouping many multidimensional objects is self-organizing maps (SOM), an unsupervised neural network algorithm able to find relationships among data. SOM groups and maps them topologically. However, it may be difficult to identify clusters with the usual visualization tools for SOM. We propose a simple algorithm to identify and visualize clusters in SOM (the RP-Q method). The RP is a new node-adaptive attribute that moves in a two dimensional virtual space imitating the movement of the codebooks vectors of the SOM net into the input space. The Q statistic evaluates the SOM structure providing an estimation of the number of clusters underlying the data set. The SOM-RP-Q algorithm permits the visualization of clusters in the SOM and their node patterns. The algorithm was evaluated in several simulated and real GEP data sets. Results show that the proposed algorithm successfully displays the underlying cluster structure directly from the SOM and is robust to different net sizes.

We previous identified adenosine 5'-diphosphate-ribosylation factor (ARF)-guanine nucleotide-exchange protein, 100 kDa (GEP(100)), as a novel GEP with a molecular size of approximately 100 kDa, which preferentially activates ARF6. In this study, we examined the effect of ARF-GEP(100) on monocytic cell apoptosis. Overexpression of ARF-GEP(100) in PMA-differentiated human monocyte-macrophage-like U937 cells and mouse macrophage RAW264.7 cells induced apoptotic cell death, which was detected by morphological changes (chromatin condensation, nucleus fragmentation, and shrinking of cytoplasm), annexin V-staining, and TUNEL assay. It is interesting that a mutant lacking the Sec7 domain, which is responsible for ARF activation, was able to induce apoptosis of the target cells to the level of that of a wild-type ARF-GEP(100). Furthermore, ARF-GEP(100)-silencing experiments indicated that the TNF-alpha-induced apoptosis was significantly suppressed among ARF-GEP(100)-depressed cells. These observations apparently suggest that ARF-GEP(100) is involved in the induction of apoptosis in monocytic phagocytes, possibly independent of ARF activation.

It has long been disputed whether mammalian enterochromaffin (EC-) cells contain a peptide in addition to serotonin. Previous immunohistochemical studies have provided evidence for the presence of enkephalins in EC-cells. These findings, however, are equivocal. Therefore, the problem of opioid peptides in EC-cells has been re-examined in the gastro-intestinal mucosa of dog, guinea-pig and man. A battery of antisera against derivatives of pro-opiomelanocortin, pro-enkephalin and pro-dynorphin have been applied to semithin serial sections of the tissues, in combination with fluorescence histochemistry and serotonin immunocytochemistry. Our findings indicate that EC-cells of the investigated species contain pro-dynorphin-related peptides, i.e. dynorphin A and alpha-neo-endorphin, but no derivatives from pro-opiomelanocortin or pro-enkephalin. Since remarkable interspecies variations occur with respect to the number and staining characteristics of opioid immunoreactive EC-cells, it is concluded that pro-dynorphin shows specific routes of post-translational processing depending upon the species and the gastro-intestinal segment investigated. Future studies should focus on the mutual relationships between serotonin and dynorphins and on the physiological significance of these peptides in the gastrointestinal tract.

Well-to-moderately differentiated neuroendocrine tumors of gastroesophageal and pancreatic origin (GEP-NETs) with liver metastasis are a heterogeneous group of malignancies for which a range of therapeutic options have been employed. Surgical resection of hepatic metastases or hepatic artery embolization may be beneficial in patients with hepatic-predominant metastatic disease. Patients with "carcinoid" syndrome and syndromes associated with functional pancreatic NET (PNET) can be effectively treated with somatostatin analogs. On the other hand, the efficacy of systemic chemotherapy for these patients is limited. A placebo-controlled, double-blind, prospective, and randomized study showed that octreotide LAR improves progression-free survival in patients with advanced midgut functional "carcinoids." In patients with advanced pancreatic NET, randomized, placebo-controlled studies have recently demonstrated that treatment with the tyrosine kinase inhibitor sunitinib or with mTOR inhibitor everolimus is associated with improved progression-free survival. Based on these studies, octreotide LAR, sunitinib, or everolimus are now considered as first-line therapeutic options in patients with advanced NET. Future studies will likely further define the role of these agents in patients with carcinoid liver metastasis and pancreatic NET liver metastasis.

Successful treatment of unresectable and metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs) requires the thoughtful choice of systemic therapy as a component of a multidisciplinary therapeutic approach. The role of somatostatin analogues is established in symptom relief, but the efficacy of interferon and radiopeptide targeted therapy is not clear. The utility of a variety of tyrosine kinase and antiangiogenic agents is variable and under investigation, whereas the role of cytotoxic chemotherapy in poorly differentiated GEP-NETs is accepted. Overall, the ideal treatment of more indolent tumors is less certain. Reassessments of the GEP-NET pathology classification has provided improved logic for the role of a variety of agents, whereas the precise positioning of many new agents that target molecular pathways of angiogenesis and proliferation is under examination. This article describes the current options for systemic therapy for GEP-NETs within the framework of the current World Health Organization classification system.

Constituting about 1-2% of all tumors of the pancreas, pancreatic neuroendocrine tumors (PNETs) are a subgroup of gastroenetropancreatic neuroendocrine tumors (GEP-NETs) with distinct tumor genetics, biology, and clinicopathological features. Surgical resection is amenable only in a minority of the cases so systemic therapies are considered in most of them. The goals of medical treatment are to control the associated symptoms and signs of the specific tumors and to shrink the tumor mass. Somatostatin analogues can, not only decrease the secretion of peptides and inhibit their functions but also stop tumor growth. Other medical options for limiting tumor growth include interferon, systemic chemotherapy, and targeted therapies including, angiogenesis inhibitors, epidermal growth factor inhibitors, and mTOR inhibitors. Newer agents are tested and the treatment options expected to increase in the near future. Meanwhile optimal use of the available therapeutic strategies is critical.