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Review [Abstract] In the last several years, researchers have exhibited an intense interest in the evolutionarily conserved signaling pathways that have crucial roles during embryonic development. Interestingly, the malfunctioning of these signaling pathways leads to several human diseases, including cancer. The chemical and biophysical events that occur during cellular signaling, as well as the number of interactions within a signaling pathway, make these systems complex to study. In silico resources are tools used to aid the understanding of cellular signaling pathways. Systems approaches have provided a deeper knowledge of diverse biochemical processes, including individual metabolic pathways, signaling networks and genome-scale metabolic networks. In the future, these tools will be enormously valuable, if they continue to be developed in parallel with growing biological knowledge. In this study, an overview of the bioinformatics resources that are currently available for the analysis of biological networks is provided.

In the last several years, researchers have exhibited an intense interest in the evolutionarily conserved signaling pathways that have crucial roles during embryonic development. Interestingly, the malfunctioning of these signaling pathways leads to several human diseases, including cancer. The chemical and biophysical events that occur during cellular signaling, as well as the number of interactions within a signaling pathway, make these systems complex to study. In silico resources are tools used to aid the understanding of cellular signaling pathways. Systems approaches have provided a deeper knowledge of diverse biochemical processes, including individual metabolic pathways, signaling networks and genome-scale metabolic networks. In the future, these tools will be enormously valuable, if they continue to be developed in parallel with growing biological knowledge. In this study, an overview of the bioinformatics resources that are currently available for the analysis of biological networks is provided.

Microtubules and tubulin are major dynamic and structural cellular components that play a key role in several cell functions, including division, signalling and intracellular trafficking. Normal epithelial cells have a highly structured, rigid cytoskeletal network that is compatible with cell motility. Thus, tubulin and microtubules are compelling cellular targets for chemotherapy. In fact, among anticancer agents, those that target microtubules constitute one of the most effective classes of chemotherapeutics in cancer. The list of compounds that target either tubulin or microtubules is extensive and consists of chemically unique compounds that bind to the tubulin dimers and destabilize microtubules (Vinca alkaloids) and those that bind to the microtubule polymer and stabilize microtubules (taxanes). Tumour-induced angiogenesis, the formation of new capillaries from existing blood vessels, and epithelial-mesenchymal transition are two steps that are critical for both tumour growth and metastatic spread. Three possible mechanisms of action are described with vinflunine, the new-generation Vinca alkaloid to arrive in clinical practice are as follows: it acts against tubulin and microtubules, disrupts newly formed blood vessels and seems to be able to reduce the metastatic process as shown in preclinical studies. These findings support the hypothesis that vinflunine, by blocking microtubule functions that contribute to cell shape, polarization, migration and other processes, might be responsible not only for tumour-cytostatic but also for specific antiangiogenic or antiepithelial-mesenchymal transition effects.

[Abstract] Genes of the Wnt and Frizzled class, expressed in HNSCC tissue and cell lines, have an established role in cell morphogenesis and differentiation, and also they have oncogenic properties. We studied Wnt and Fz genes as potential tumor-associated markers in HNSCC by qPCR. Expression levels of Wnt and Fz genes in 22 unique frozen samples from HNSCC were measured. We also assessed possible correlation between the expression levels obtained in cancer samples in relation to clinicopathologic outcome. Wnt-1 was not expressed in the majority of the HNSCC studied, whereas Wnt-5A was the most strongly expressed by the malignant tumors. Wnt-10B expression levels were related with higher grade of undifferentiation. Related to Fz genes, Fz-5 showed more expression levels in no-affectation of regional lymph nodes. Kaplan–Meier survival analyses suggest a reduced time of survival for low and high expression of Wnt-7A and Fz-5 mRNA, respectively. qPCR demonstrated that HNSCC express Wnt and Fz members, and suggested that Wnt and Fz signaling is activated in HNSCC cells.

468 Background: Detection of circulating tumor cells (CTC) may provide diagnostic and prognostic information in genitourinary tumors (GT). The aim of this work was identify aberrantly expressed miRNAs potentially useful for CTC detection in blood samples from patients with GT to assess their potential clinical significance, and to gain a greater understanding of the mechanisms driving tumor progression. Methods: We examined blood levels of 92 microRNAs in 113 metastatic patients: prostate (mP), renal cell carcinoma (mRCC), bladder tumors (mB) and healthy volunteers (HV) (N=18) using SYBR-green-based microRNA RT-qPCR arrays (Exiqon). Array design was made by literature review and bioinformatics approach using free databases. Relative Expression Software Tool (REST) and SPPS 21.0 were used to data processing and analysis. Results: microRNAs differential expressed between tumors and HV (only up-regulated miRNAs are shown in Table). Conclusions: microRNAs in the circulation are relatively stable, very accessible, low invasive and easily testable biomarkers. These results suggest that our bioinformatic approach is an useful high-throughput method to identified tumors-associated miRNAs. The selected miRNAs should be further evaluated for their potential as markers for CTC detection, prognosis and therapeutic outcome. Further studies of precision and sensitivity on these markers in this GT population will clarify its role as novel stable blood-based markers. [Table: see text]

In 1978, Schofield hypothesized the existence of cells in the proximity of stem cells, termed the stem cell niche, that have the ability to extrinsically exert influence on stem cell behavior. Indeed, a large body of evidence from a number of stem cell systems validated this hypothesis by affirming the critical importance of stem cell niche interactions and localized extracellular signals in regulating stem cell self-renewal and differentiation. This concept is precisely illustrated in the bone marrow transplantation setting in which the success of the transplant is contingent on the ability of hematopoietic stem cells (HSCs) to home and seed appropriate secondary supportive niches of intravenous infection.

451 Background: Renal cell carcinoma (RCC) is known to be resistant to chemotherapy. There is need for the identification of biomarkers capable to determine RCC prognosis factors and metastatic potential obtainable from non-invasive or minimally invasive techniques. Our aim was to derive predictive models which could predict more accurately than any one factor alone. Methods: To studythe cascade of events leading to the formation and progression of RCC, we assessed 29 markers by immunohistochemistry and qRT-PCR using tissue micro-array (TMA). Results: Multivariate logistic regression showed the best proteins combination for node status (NOTCH1 and GLUT5) and pelvis invasion (EGFR and DLL3). ROC curve analyses were made to analyse the accuracy of the best candidate proteins; it should be noted NOTCH1 and GLUT5 for node status prediction (AUC=0.833, 95% CI, 0.744-0.922; p

Historically, cell-signaling pathways have been studied as the compilation of isolated elements into a unique cascade that transmits extracellular stimuli to the tumor cell nucleus. Today, growing evidence supports the fact that intracellular drivers of tumor progression do not flow in a single linear pathway, but disseminate into multiple intracellular pathways. An improved understanding of the complexity of cancer depends on the elucidation of the underlying regulatory networks at the cellular and intercellular levels and in their temporal dimension. The high complexity of the intracellular cascades causes the complete inhibition of the growth of one tumor cell to be very unlikely, except in cases in which the so-called “oncogene addiction” is known to be a clear trigger for tumor catastrophe, such as in the case of gastrointestinal stromal tumors or chronic myeloid leukemia. In other words, the separation and isolation of the driver from the passengers is required to improve accuracy in cancer treatment. This review will summarize the signaling pathway crossroads that govern renal cell carcinoma proliferation and the emerging understanding of how these pathways facilitate tumor escape. We outline the available evidence supporting the putative links between different signaling pathways and how they may influence tumor proliferation, differentiation, apoptosis, angiogenesis, metabolism and invasiveness. The conclusion is that tumor cells may generate their own crossroads/crosstalk among signaling pathways, thereby reducing their dependence on stimulation of their physiologic pathways.

Guadalupe Aparicio Gallego1, Vanessa Medina Villaamil1, Ana Capdevila Puerta2, Enrique Grande Pulido3 and L.M. Anton Aparicio4,5 1Biomedical Research Institute, A Coruna University Hospital, A Coruna, 2Anatomic Pathology Service, A Coruna University Hospital, A Coruna, 3Medical Oncology Service, Ramon y Cajal University Hospital, Madrid, 4Medical Oncology Service, A Coruna University Hospital, A Coruna 5Medicine Department, University of A Coruna, A Coruna Spain

In 1889, Sir S. Paget introduced the soil and seed hypothesis of metastasis to medicine and credited the idea to Fuchs. In Paget s study, he concluded that the distribution of metastases cannot be due to chance alone and that different tissues provide optimal conditions for the growth of specific cancers. In the soil and seed metaphor, the soil refers to the secondary site of tumour growth and development and perhaps the chemical signals produced in the microenvironment at the sites of metastasis. The seed is the ostensible stem cell or tumourinitiating cell from the primary tumour. These tumour-initiating cells are the tumorigenic force behind tumour initiation, growth, metastasis, drug resistance, and relapse. In a variation of this idea, called the homing hypothesis, a secondary signal secreted by cells at the future metastatic sites “calls” the tumour cells to the site and permits them to proliferate in the new environment. In this hypothesis, the seed produces cell surface receptors that are able to recognise the site demarcated by the soil. Although the mechanisms that define tissue specificity remain obscure, researchers have focused on small messenger molecules as attractants and larger cell surface receptors that guide the tumour-initiating cells. Based on the hypothesis introduced by Paget, other groups have focused on chemokines and their receptors as viable candidates for soil and seed signalling and have proposed a “spatial and temporal code” composed of specific combinations of such molecules, while other molecules are responsible for neovascularisation, metastasis, and immunosurveillance avoidance. Lung cancers result from complex genetic and epigenetic changes and are characterised by stepwise malignant progression of cancer cells with an associated accumulation of genetic alterations. This process, referred to as multistep carcinogenesis, develops through the clonal evolution of initiated lung cells. Initiation consists of the acquisition of defined genetic alterations in a small number of genes that confer a proliferative advantage and facilitate progression towards invasive neoplasia. Although many of these genetic changes occur independently of histological type, their frequency and timing of occurrence with respect to cancer progression differ between small cell lung carcinomas (SCLC), which may originate from epithelial cells with neuroendocrine features, and non-SCLCs, which

A growing understanding of the underlying molecular biology of renal cell carcinoma (RCC) has identified several pathways pertinent to its pathophysiology. Cellular hypoxia and metabolic stress have been observed in many cancer types. Hypoxia-induced factor (HIF) is considered a central regulator of oxygen homeostasis. The HIF transcription factor complex has been demonstrated to transcriptionally induce the expression of genes involved in angiogenesis, anaerobic glucose metabolism, cell motility and metastasis, growth and survival, apoptosis, and telomere maintenance. Notable genes induced by HIF that are involved in angiogenesis include vascular endothelial growth factor (VEGF) and plateletderived growth factor (PDGF), as well as other proangiogenic factors, such as angiopoietin-4 (Ang4). These factors promote the proliferation, migration, and maturation of endothelial cells and pericytes supporting the recruitment of vessels or neoangiogenesis necessary to restore blood supply to an ischemic region. In the case of RCC, this process leads to the rampant, disorganised proliferation of vessels in this highly vascular tumour type. Additional factors include proteins involved in promoting the cellular switch to anaerobic glycolysis, such as the glucose transporter Glut1; enzymes of glucose metabolism, such as hexokinase (HK) and lactate dehydrogenase (LDH), the antigen carbonic anhydrase IX (CAIX, also called G250) and the lactate transporter MCT-4. This hypoxic repertoire of gene upregulation likely contributes to the highly glycolytic phenotype of RCC, even in the presence of abundant oxygen with which to perform oxidative phosphorylation for energy generation. Like other processes that integrate endothelial cell vascular network expansion, tumour angiogenesis is dependent on secreted VEGF to promote existing vessel in growth into the tumour and the expansion of vascular networks by neovascularisation. Inappropriate activation of the hypoxia response pathway is a major mechanism of VEGF transcriptional regulation in RCC. A variety of mechanisms account for the increase in VEGF, with activation of the hypoxic response pathway via the transcription factors HIF1-┙ and HIF2-┙ as the classic mechanism of induction.

The introduction of targeted therapy represents a major advance in the treatment of tumor progression. Targeted agents are a novel therapeutic approach developed to disrupt different cellular signaling pathways. The tyrosine kinase inhibitor sunitinib specifically blocks multiple tyrosine kinase receptors that are involved in the progression of many tumors. Sunitinib is the current standard of care in first-line treatment of advanced renal cell carcinoma, and it is approved in imatinib-intolerant and imatinib-refractory gastrointestinal stromal tumors. However, it is increasingly evident that sunitinib may display collateral effects on other proteins beyond its main target receptors, eliciting undesirable and unexpected adverse events. A better understanding of the molecular mechanisms underlying these undesirable sunitinib-associated side effects will help physicians to maximize efficacy of sunitinib and minimize adverse events. Here, we focus on new insights into molecular mechanisms that may mediate sunitinib-associated adverse events. Mol Cancer Ther; 10(12); 2215–23. ©2011 AACR.

[Abstract] Asthenia-fatigue syndrome (AFS) is defined as a persistent, subjective sense of tiredness related to cancer or its treatment and greatly impacts quality of life among cancer patients. All tyrosine kinase inhibitors, but especially sunitinib, may induce AFS. The reason for sunitinib-induced AFS is not yet well understood. Adverse events caused by sunitinib associated with AFS may include anemia, hypothyroidism, nausea and vomiting. However, AFS is also reported when active treatment with sunitinib is ongoing, and no other relevant adverse event can justify it. The molecular mechanisms by which sunitinib triggers AFS remain elusive. Sunitinib displays multiple off-target tyrosine-kinase interactions and competitively inhibits multiple proteins through the blockade of their ATP-binding sites. The broad spectrum of kinases inhibited may play a key role not only in terms of activity but also in terms of toxicity induced by sunitinib. This study considered different clinical observations and current metabolic and pharmacological knowledge, leading to hypotheses regarding which molecular mechanisms may be involved in sunitinib-induced AFS in cancer patients. Deeper knowledge of the molecular mode of action of sunitinib may lead to improved optimization of its clinical use.

Stem cells within many tissues are thought to reside within a niche formed by a group of surrounding cells and their extracellular matrices, which provide an optimal microenvironment for the stem cells to function. In general, the niche is thought to consist of a highly organized microenvironment in which various factors, such as signals coming from secreted cytokines, extracellular matrix interactions, and intercellular adhesion, are thought to work cooperatively to maintain the undifferentiated stem cell phenotype. Among stem cells, adult stem cells are often localized into specific niches where they utilize many, but not necessarily all, of the external and intrinsic factors used by the embryonic counterparts in selecting a specific fate. Within the niche, stem cells are able to maintain their ability for selfrenewal as well as their potential so that, consequently, detachment from the niche compartment induces stem cell differentiation and loss of self-renewal. Thus, when a stem cell begins to divide, it is thought that one daughter cell remains into niche to replace the original stem cell whereas other daughter cell is expelled out of niche and starts its process of differentiation. In this process, a cell retains self-renewal and differentiation inhibitory factors, so that keep being stem cell, whereas another daughter cell is destined to proliferate during a certain number of divisions for finally differentiate along a particular lineage. This latter daughter cell will receive too few stemness factors to maintain as stem cell, and/or inherit proliferation and/or differentiation factors that can overcome its stem cell phenotype. To maintain tissue homeostasis and correct functioning of organism, the number of daughter cells that retain stem cell identity must be strictly controlled such that differentiated cells can be generated in response to any injury. Likewise, the rate of division of stem cells into niche must be tightly controlled since an overproduction of daughter cells destined to be differentiated may be harmful because may result in cancer generation. In the present chapter, we speculate cancer stem cell niche for as well as the mechanisms that influence on the generation of daughter cells.

The hedgehog (Hh) pathway is one of the fundamental signal transduction pathways in animal development and is also involved in stem-cell maintenance and carcinogenesis. The hedgehog (hh) gene was first discovered in Drosophila, and members of the family have since been found in most metazoan. Hh proteins are composed of two domains, an aminoterminal domain HhN, which has the biological signal activity, and a carboxy-terminal autocatalytic domain HhC, which cleaves Hh into two parts in an intramolecular reaction and adds a cholesterol moiety to HhN. HhC has a sequence similarity to the self-splicing inteins, and the shared region is termed Hint. HhN is modified by cholesterol at its carboxyl terminus and by palmitate at its amino terminus in both flies and mammals. The modified HhN is released from the cell and travels through the extracellular space. On binding its receptor Patched, it relieves the inhibition that Patched exerts on Smoothened, a G-proteincoupled receptor. The resulting signalling cascade converges on the transcription factor Cubitus interruptus (Ci), or its mammalian counterparts, the Gli proteins, which activate or repress target genes. The Hh family of morphogens plays important instructional roles in the development of numerous metazoan structures (Ingham & McMahon, 2001). The Hh ligands, Sonic, Indian and Desert Hh in vertebrates and Hh in Drosophila, signal through binding to the membrane receptor Patched (Ptc) (Chen & Struhl, 1996), to reverse the Ptcmediated inhibition of signalling by the trans-membrane protein Smoothened (Smo) (Alcedo et al., 1996). This allows Smo to activate the intracellular signalling components, resulting in stabilization of down-stream transcriptional activator(s) and activation of target genes (Hooper & Scott, 1989). Transcription activation is facilited through the Gli family of transcription factors in vertebrates (Ingham & McMahon, 2001). Hh signalling can initiate cellular growth, division, lineage specification, axon guidance and function as a survival factor (Cohen, 2009). Given this range of biological functions, it is not surprising that mutations in components of the Hh pathway are associated with both developmental defects and tumor progression (Cohen, 2009). Disruption of PTC, which functions as a negative regulator of the pathway, is implicated in cancer development in both inherited and sporadic cancers. Mutations in PTC and/or SMO trigger inappropriate activation of the Hh pathway, and have been identified in tumor types including basal cell carcinoma

Primary lung cancer may arise from the central (bronchial) or peripheral (bronchiolo-alveolar) compartments. However the origins of the different histological types of primary lung cancer are not well understood. Stem cells are believed to be crucial players in tumour development and there is much interest in identifying those compartments that harbour stem cells involved in lung cancer. Although the role of stem cells in carcinogenesis is not well characterised, emerging evidence is providing new insights into this process. Numerous studies have indicated that lung cancer is not a result of a sudden transforming event but a multistep process in which a sequence of molecular changes result in genetic and morphological aberrations. The exact sequence of molecular events involved in lung carcinogenesis is not yet well understood, therefore deeper knowledge of the aberrant stem cell fate signalling pathway could be crucial in the development of new drugs against the advanced setting.

Over the past decade a number of vascular complications have emerged, such as newly developed or worsened hypertension, in patients who were administered with new cancer treatments for several types of cancer that were untreatable earlier. Hypertension is emerging as one of the most common adverse effects of therapy with angiogenesis inhibitors. Small-molecule inhibitors of vascular endothelial growth factor signalling are associated with a high proportion of patients with hypertension. The mechanisms underlying the development of hypertension are not well known, although there seem to be several mechanisms. Physiopathology of hypertension implicates abnormalities in endothelial function and angiogenesis. Several features of hypertensive patients are reduced number of arterioles and capillaries, alterations of the microvascular network, decrease in vascular wall compliance and flexibility, reduced nitric oxide bioactivity and increases in plasma vascular endothelial growth factor. Treatment with tyrosine kinase inhibitors (TKIs) is associated with a significant and sustained increase in blood pressure. We suspect that TKIs exert their hypertensive effects directly at the level of the microvascular network through processes such as vascular rarefaction, endothelial dysfunction and/or altered nitric oxide metabolism. This study shows the vascular complications of treatment with a TKI, sunitinib (SU11248), with special emphasis on hypertension.

[Abstract] In recent years, it has been proposed that tumours are not homogeneous but composed of several cellular types like normal tissues. A cellular subtype, which is though to be the origin of tumours as well as their malignant properties (i.e., capacity for regrowth and metastasis), are the cancer stem cells (CSCs). CSCs, like normal stem cells, have a nearly unlimited capacity to self-renew and to proliferate so that are responsible, besides their same auto-perpetuation giving rise to the features previously depicted, also for the generation of the bulk of more differentiated cells in tumour. The altered behaviour of CSCs may be caused by the malfunction of a number of signalling pathways involved in normal embryonic development and in tissue homeostasis in adulthood. Among these signalling pathways are Wnt, Hedgehog, Notch and BMP pathways. In this review, we will focus on the study of molecular aspects of BMP signalling as well as its involvement in cancer.

[Abstract] Cancer is a heritable disorder of somatic cells: environment and heredity are both important in the carcinogenic process. The primal force is the “two hits” of Knudson’s hypothesis, which has proved true for many tumours, including renal cell carcinoma. Knudson et al. [1, 2] recognised that familial forms of cancer might hold the key to the identification of important regulatory elements known as tumour-suppressor genes. Their observations (i.e., that retinoblastoma tend to be multifocal in familial cases and unifocal in sporadic presentation) led them to propose a two-hit theory of carcinogenesis. Furthermore, Knudson postulated that patients with the familial form of the cancer would be born with one mutant allele and that all cells in that organ or tissue would be at risk, accounting for early onset and the multifocal nature of the disease. In contrast, sporadic tumours would develop only if a mutation occurred in both alleles within the same cell, and, as each event would be expected to occur with low frequency, most tumours would develop late in life and in a unifocal manner [3, 4]. The kidney is affected in a variety of inherited cancer syndromes. For most of them, both the oncogene/tumour-suppressor gene involved and the respective germline mutations have been identified. Each of the inherited syndromes predisposes to distinct types of renal carcinoma. Families with hereditary predisposition to cancer continue to provide a unique opportunity for the identification and characterisation of genes involved in carcinogenesis. A surprising number of genetic syndromes predispose to the development of renal cell carcinoma, and genes associated with five of these syndromes have been already identified: VHL, MET, FH, BHD and HRPT2. Few cancers have as many different types of genetic predisposition as renal cancer, although to date only a small proportion of renal cell cancers can be explained by genetic predisposition.

448 Background: Many studies have demonstrated genetic and environmental factors lead to renal cell carcinoma (RCC) occurring during a protracted period of tumorigenesis. It seemed suitable identify and characterize potential molecular markers which might provide rapid and effective possibilities for early detection of RCC. The purpose from this analysis was to derive predictive models which could predict more accurately than any one factor alone. Methods: We assessed using quantitative real-time PCR (qPCR) with SYBR Green the profile of 32 predictive markers involved in the cascade of events leading to the formation and progression of this disease to evaluate their involvement in oncogenesis. RNA of quality was obtained in 90% of samples (N=80, 52/80 clear RCC, 6/80 papillary RCC and 14/80 chromophobe RCC) to carry out the study of gene expression. GenEx software was used for qPCR data processing and analysis. The potential correlation between mRNA expression and the pathological features of the study subjects was assessed by Pearson Chi-squared. Linear rather than logistic regression models were used (SPSS statistics 21.0 software). Additionally, a knowledgebases of biological pathways, Reactome and Snow (Babelomics), were used to superimpose our quantitative expression data. Results: The best gene predictors related to different pathological variables (histological type, tumor size, Fuhrman grade, number of involved nodes, renal pelvis invasion, lymphatic vessels invasion, and rupture of the renal capsule): Hif1-α (p < 0.001), Hif1-β (p = 0.035), DLL1 (p = 0 .012), DLL3 (p< 0.001), c-Kit (p = 0.002), PDGFR-β (p =0.002), PDGFR-α (p = 0.026), Bax-β (p = 0.005), Survivin (p = 0.028), Notch1 (p = 0.006), Notch2 (p = 0.007), Notch3 (p = 0.016), Notch4 (p = 0.005), EGFR (p = 0.029), Glut3 (p = 0.026), Glut5 (p = 0.036), FH (p = 0.018), CA9 (p = 0.030), and VHL-1(p = 0.015). Conclusions: Our data suggested that altered expression of certain members involved in the main pathways which feed RCC and their downstream targets analyzed together could improve the diagnostic accuracy for renal cancer by combining determinations of mRNA markers.

e15077 Background: Renal cell carcinomas (RCC) constitute a morphologically and genetically heterogeneous tumor.Wnt proteins are a large family of secreted glycoproteins that activate intracellular signal transduction pathways to control a wide variety of cellular processes such as determination of cell fate, proliferation, migration, and polarity.Wnt signalling may be playing a central role during RCC development. Methods: To characterize Wnt signalling activity in RCC, we gathered 48 tumor samples from patients diagnosed with metastatic RCC between years 2006 and 2011. Expression levels of Wnt family members (Wnt1, Wnt2, Wnt3a, Wnt4, Wnt5a, Wnt7a, and Wnt9a) were examined by real-time PCR and immunohistochemistry in tumor and normal tissue from removed kidneys. Results: Wnt1 and Wnt5a were up-regulated in clear cell RCC being their relative expression 2.4.103 (Wnt1) and 4.102 (Wnt5a) times higher in renal tumor tissue than in normal tissue. One-way ANOVA test showed Wnt3a and Wnt4 as the best protein markers to distinguish clear cell RCC (F=3.95, p=0.010 and F=3.05, p=0.029, respectively). Wnt1 and Wnt7a were over-expressed in those cases which had undergone nefrectomy (Mann-Whitney U test p=0.065 and p=0.056 respectively). Finally, Wnt2 protein level was associated with those patients with high risk prognosis (Kruskal-Wallis test p=0.001). Conclusions: Our results indicate that Wnt3a and Wnt4 are potentially useful immunohistochemical markers for the differential diagnosis between clear cell RCC and other subtypes of RCC and also suggest a role for Wnt2 as a high risk prognosis marker.

e15076 Background: The characterization of factors involved in the etiology of renal cell carcinoma (RCC) may lead to the identification of new targets for therapy and prognostic markers. Recent data indicate that Notch family members can be expressed by malignant RCC cells and this expression may have potential use as a strong prognostic factor. The aim of this study was to investigate the potential of Notch family members as prognostic markers for stage IV patients. Methods: We analyzed, by means of immunohistochemistry and quantitative polymerase chain reaction, protein and mRNA levels of 4 Notch family members in tumor specimens obtained from 48 patients with stage IV RCC. Clinicopathological data for these patients were evaluated. A 34% of the population had hypertension, 7.3% had hypothyroidism, 19.5% were diabetic, 7.7% prediabetic, and 22% showed hyperlipidemia. RCC specimens included clear cell RCC: 34; papillary: 3; mixed: 1; undifferentiated: 1; hypernephroma: 1.The association among biomarkers and clinicopathological factors were explored using One-Way ANOVA test and non-parametric statistics, Mann-Whitney U and Kruskal-Wallis tests. Results: Relative expression of Nocth3 and Notch4 transcript levels were elevated 25-fold in clear cell RCC tumors when compared with normal kidney tissues. Notch1 and Notch2 were overexpressed at protein level in clear cell RCC (p>0.05). Those renal tumors with right localization showed highest levels of Notch4 protein (p=0.096). Notch2 overexpression was associated with patients who had undergone nefrectomy (p=0.038). Finally, Bonferroni post-hoc statistic test showed us a statistically significant association (p = 0.020) between Nocth1 protein expression levels and patients with medium risk prognosis. Conclusions: These results show a deregulated expression of Notch receptors in RCC and suggest a role for this pathway in the progression of this tumoral pathology.

e15079 Background: Many studies have demonstrated genetic and environmental factors lead to renal cell carcinoma (RCC) occurring during a protracted period of tumorigenesis. It seemed suitable identify and characterize potential molecular markers appearing during of tumorigenesis which might provide rapid and effective possibilities for early detection of RCC. Methods: We assessed using quantitative real-time PCR (qPCR) the profile of 32 markers involved in the cascade of events leading to the formation and progression of RCC: invasiveness, angiogenesis and antiapoptotic mechanisms. RNA of quality was obtained in 90% of samples (N=80, 64/80 clear RCC, 8/80 papillary RCC and 8/80 chromophobe RCC) to carry out the study of gene expression. Nonparametric tests (Pearson's correlation coefficient test and Spearman's rho test, Kruskal — Wallis and Mann — Whitney) and Bonferroni post-hoc test were applied for statistical data analysis. Additionally, a knowledgebase of biological pathways, Reactome, was used to superimpose our quantitative expression data. Results: Statistical analysis comparing medians and means showed the following candidates as the best gene predictors related to different pathological variables (histological type, number of involved nodes, renal pelvis invasion, lymphatic vessels invasion and rupture of the renal capsule): Hif1-α (p

405 Background: MicroRNAs (miRNAs), a class of small RNAs, have been intensely investigated recently because of their important regulatory role in gene expression. Circulating miARNs are potential biomarkers for cancer not only abundant in blood, but also very stable, which are important prerequisites as clinical biomarkers. Detection of circulating tumor cells (CTC) may provide diagnostic and prognostic information in genitourinary renal tumors. The aim of this work is identify miRNAs potentially useful for CTC detection in blood samples from patients with renal tumors to assess their potential clinical significance. Methods: We examined blood levels of three miRNAs, let-7c, miR-200c and miR-31 in 48 patients with renal tumors with locally advanced or metastatic disease and 18 healthy persons using quantitative real-time PCR. The clinicopathologic characteristics of the population under consideration include among other: sex, age, tumor location, histological type, Fuhrman grade, tumor size, number of involved nodes, tumor stage, time to progression and overall survival. Results: We found that the median levels of miRNAs, let-7c, miR-200c and miR-31 were significantly higher in patients with renal tumors than those in healthy controls (p=.002, p=.000 and p=.004, respectively). Receiver-operator characteristic (ROC) curve analyses indicate that these blood miRNAs may be useful markers for discriminating patients with renal tumors from healthy controls (AUC=.750, AUC=.853 and AUC=.738, respectively). Conclusions: miRNAs in the circulation are relatively stable, very accessible, low invasive and easily testable biomarkers. Our results suggest let-7c, miR-200c and miR-31 as novel stable blood-based markers for renal cancer detection. This work was supported by Grants PI07/0477 from Fondo de Investigaciones Sanitarias (FIS), Instituto de Salud Carlos III.S. Díaz Prado is supported by an Isidro Parga Pondal research contract by Xunta de Galicia (A Coruña, Galicia, Spain). Cancer research in our laboratory is supported by the “Fundación do CHU A Coruña”.

421 Background: Renal cell carcinoma (RCC) is the most common type of kidney cancer. It is required a better understanding of signalling pathways involved in renal cells. Methods: We assessed using immunohistochemistry (IHC) and quantitative real-time PCR (qPCR) with SYBR Green the profile of predictive markers involved in the cascade of events leading to the formation and progression: invasiveness, angiogenesis and antiapoptotic mechanisms. 80 RCC tissues were detected by IHC. RNA of quality only was obtained in 72 (80% clear RCC, 10% papillary RCC and 10% chromophobe RCC) to carry out the study of gene expression through qPCR. A pool of normal kidney-derived RNA samples (N=5) was used as healthy control. GAPDH and YWHAZ were used as reference genes. GenEx software was used for qPCR data processing and analysis. Nonparametric tests (Pearson’s correlation coefficient test and Spearman’s rho test, Kruskal — Wallis and Mann — Whitney) were applied for statistical data analysis (SPSS 19). Results: p53 showed higher expression in those cases with Furhman grade I (p=0.036). Moreover p53 showed a positive association with VEGF, GLUT1, GLUT4, VEGFR-2 and VHL (r=0.241, sig. level 0.05; r=0.291, sig. level 0.01; r=0.456, sig. level 0.01; r=0.187, sig. level 0.097 and Spearman’s rho=0.269, sig. level 0.05 respectively). Hif1- α, Hif1- β, Notch1 and Notch3 were upregulated in chromophobe RCC (p=0.045, p=0.03, p=0.03 and p=0.02 respectively). Hif1- α and Notch3 were upregulated in clear RCC (p=0.034 and p=0.041 respectively). Spearman’s correlation coefficient showed a strong positive correlation between Nocth1-4 members and their receptors and Hif1-α and β genes. Highlight the correlation found between: Notch1 and Hif1-α (Spearman’s rho = 0.740, significance level 0.01) and Hif1-β and Jagged1 (Spearman’s rho = 0.752, significance level 0.01). Conclusions: The pathway involving the tumor suppressor gene p53 could regulate tumor angiogenesis. Co-expression of Notch receptors, their ligands and Hif-1 α and Hif1- β subunits may play a role in human RCC. Notch cascade may represent a novel and therapeutically accessible pathway in chromophobe and clear RCC. More detailed studies of these crossing pathways are in progress.