239 resultados para Cancer of the duodenum
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Abstract Background. The broad spectrum of antitumor activity of both the oral platinum analogue satraplatin (S) and capecitabine (C), along with the advantage of their oral administration, prompted a clinical study aimed to define the maximum tolerated dose (MTD) of the combination. Patients and methods. Four dose levels of S (mg/m(2)/day) and C (mg/m(2)/day) were evaluated in adult patients with advanced solid tumors: 60/1650, 80/1650, 60/2000, 70/2000; a course consisted of 28 days with sequential administration of S (days 1-5) and C (days 8-21) followed by one week rest. Results. Thirty-seven patients were treated, 24 in the dose escalation and 13 in the expansion phase; at the MTD, defined at S 70/C 2000, two patients presented dose limiting toxicities: lack of recovery of neutropenia by day 42 and nausea with dose skip of C. Most frequent toxicities were nausea (57%), diarrhea (51%), neutropenia (46%), anorexia, fatigue, vomiting (38% each). Two partial responses were observed in platinum sensitive ovarian cancer and one in prostate cancer. Conclusion. At S 70/C 2000 the combination of sequential S and C is tolerated with manageable toxicities; its evaluation in platinum and fluorouracil sensitive tumor types is worthwhile because of the easier administration and lack of nephro- and neurotoxicity as compared to parent compounds.
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We describe the preparation of the modified chelator aminooxyacetyl-ferrioxamine, and the replacement of its iron atom by 67Ga at high specific activity. The aminooxy function of this compound was allowed to react with the aldehyde groups generated by the periodate oxidation of the oligosaccharide of a mouse IgG1 monoclonal antibody (MAb) directed against carcino-embryonic antigen (CEA). The use of the aminooxy group allowed a stable bond to be formed between the chelon and the antibody with no need for reduction. Iron was removed from the ferrioxamine moiety and replaced by 67Ga either before or after conjugation of the chelon to the antibody. In either case the labelled antibody was injected into nude mice bearing a human colon carcinoma having the appropriate antigenicity. Unoxidized antibody, labelled with 125I by conventional methods, was co-injected as an internal control. Additional control experiments were carried out with a non-immune IgG using the same 67Ga-labelled modified chelon as above. The in vivo distribution of the modified antibodies was evaluated at various times between 24 and 96 hr after injection. The methods used were gamma-camera imaging and, more quantitatively, gamma-counting of the various organs after dissection. Interestingly, with the metal-chelon-labelled antibody, the intensity and specificity of tumor labelling was comparable and in some cases superior to the results obtained with radio-iodinated antibody. In particular, there was almost no increase in liver and spleen uptake of radioactive metal relative to radio-iodine, contrary to what has been observed with most antibodies labelled with 111In after conjugation with DTPA.
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Background Cruciferous vegetables have been suggested to protect against various cancers, though the issue is open to discussion. To further understand their role, we analyzed data from a network of case-control studies conducted in Italy and Switzerland. Patients and methods The studies included a total of 1468 cancers of the oral cavity/pharynx, 505 of the esophagus, 230 of the stomach, 2390 of the colorectum, 185 of the liver, 326 of the pancreas, 852 of the larynx, 3034 of the breast, 367 of the endometrium, 1031 of the ovary, 1294 of the prostate, 767 of the kidney, and 11 492 controls. All cancers were incident, histologically confirmed; controls were subjects admitted to the same network of hospitals as cases for a wide spectrum of acute nonneoplastic conditions. Results The multivariate odds ratio (OR) for consumption of cruciferous vegetables at least once a week as compared with no/occasional consumption was significantly reduced for cancer of the oral cavity/pharynx (OR = 0.83), esophagus (OR = 0.72), colorectum (OR = 0.83), breast (OR = 0.83), and kidney (OR = 0.68). The OR was below unity, but not significant, for stomach (OR = 0.90), liver (OR = 0.72), pancreatic (OR = 0.90), laryngeal (OR = 0.84), endometrial (OR = 0.93), ovarian (OR = 0.91), and prostate (OR = 0.87) cancer. Conclusion This large series of studies provides additional evidence of a favorable effect of cruciferous vegetables on several common cancers.
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Individuals carrying BRCA2 mutations are predisposed to breast and ovarian cancers. Here, we show that BRCA2 plays a dual role in regulating the actions of RAD51, a protein essential for homologous recombination and DNA repair. First, interactions between RAD51 and the BRC3 or BRC4 regions of BRCA2 block nucleoprotein filament formation by RAD51. Alterations to the BRC3 region that mimic cancer-associated BRCA2 mutations fail to exhibit this effect. Second, transport of RAD51 to the nucleus is defective in cells carrying a cancer-associated BRCA2 truncation. Thus, BRCA2 regulates both the intracellular localization and DNA binding ability of RAD51. Loss of these controls following BRCA2 inactivation may be a key event leading to genomic instability and tumorigenesis.
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Basal cell carcinoma of the skin is the most common human cancer. It is also the most frequent malignant tumor of the eyelid. In Europe, its most common clinical presentation is a hard indurated, and sometimes ulcerated nodule. The authors report a giant palpebral basal cell carcinoma in a black non albinos Cameroonian patient. The ethnic origin, localization and macroscopic aspect are discussed. The problems connected with diagnosis and treatment of malignant tumors in Africa are noted.
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BACKGROUND: Greater tobacco smoking and alcohol consumption and lower body mass index (BMI) increase odds ratios (OR) for oral cavity, oropharyngeal, hypopharyngeal, and laryngeal cancers; however, there are no comprehensive sex-specific comparisons of ORs for these factors. METHODS: We analyzed 2,441 oral cavity (925 women and 1,516 men), 2,297 oropharynx (564 women and 1,733 men), 508 hypopharynx (96 women and 412 men), and 1,740 larynx (237 women and 1,503 men) cases from the INHANCE consortium of 15 head and neck cancer case-control studies. Controls numbered from 7,604 to 13,829 subjects, depending on analysis. Analyses fitted linear-exponential excess ORs models. RESULTS: ORs were increased in underweight (<18.5 BMI) relative to normal weight (18.5-24.9) and reduced in overweight and obese categories (>/=25 BMI) for all sites and were homogeneous by sex. ORs by smoking and drinking in women compared with men were significantly greater for oropharyngeal cancer (p < 0.01 for both factors), suggestive for hypopharyngeal cancer (p = 0.05 and p = 0.06, respectively), but homogeneous for oral cavity (p = 0.56 and p = 0.64) and laryngeal (p = 0.18 and p = 0.72) cancers. CONCLUSIONS: The extent that OR modifications of smoking and drinking by sex for oropharyngeal and, possibly, hypopharyngeal cancers represent true associations, or derive from unmeasured confounders or unobserved sex-related disease subtypes (e.g., human papillomavirus-positive oropharyngeal cancer) remains to be clarified.
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The treatment of some cancer patients has shifted from traditional, non-specific cytotoxic chemotherapy to chronic treatment with molecular targeted therapies. Imatinib mesylate, a selective inhibitor of tyrosine kinases (TKIs) is the most prominent example of this new era and has opened the way to the development of several additional TKIs, including sunitinib, nilotinib, dasatinib, sorafenib and lapatinib, in the treatment of various hematological malignancies and solid tumors. All these agents are characterized by an important inter-individual pharmacokinetic variability, are at risk for drug interactions, and are not devoid of toxicity. Additionally, they are administered for prolonged periods, anticipating the careful monitoring of their plasma exposure via Therapeutic Drug Monitoring (TDM) to be an important component of patients' follow-up. We have developed a liquid chromatography-tandem mass spectrometry method (LC-MS/MS) requiring 100 microL of plasma for the simultaneous determination of the six major TKIs currently in use. Plasma is purified by protein precipitation and the supernatant is diluted in ammonium formate 20 mM (pH 4.0) 1:2. Reverse-phase chromatographic separation of TKIs is obtained using a gradient elution of 20 mM ammonium formate pH 2.2 and acetonitrile containing 1% formic acid, followed by rinsing and re-equilibration to the initial solvent composition up to 20 min. Analyte quantification, using matrix-matched calibration samples, is performed by electro-spray ionization-triple quadrupole mass spectrometry by selected reaction monitoring detection using the positive mode. The method was validated according to FDA recommendations, including assessment of extraction yield, matrix effects variability (<9.6%), overall process efficiency (87.1-104.2%), as well as TKIs short- and long-term stability in plasma. The method is precise (inter-day CV%: 1.3-9.4%), accurate (-9.2 to +9.9%) and sensitive (lower limits of quantification comprised between 1 and 10 ng/mL). This is the first broad-range LC-MS/MS assay covering the major currently in-use TKIs. It is an improvement over previous methods in terms of convenience (a single extraction procedure for six major TKIs, reducing significantly the analytical time), sensitivity, selectivity and throughput. It may contribute to filling the current knowledge gaps in the pharmacokinetics/pharmacodynamics relationships of the latest TKIs developed after imatinib and better define their therapeutic ranges in different patient populations in order to evaluate whether a systematic TDM-guided dose adjustment of these anticancer drugs could contribute to minimize the risk of major adverse reactions and to increase the probability of efficient, long lasting, therapeutic response.
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Improvement in cancer treatments resulted in an increased number of men surviving cancer. Quality of life has become an important issue in these patients. Anti cancer treatments might have transient or definitive harmful effects on male fertility. Sperm cryoconservation is currently the only proven method to preserve fertility in patients undergoing oncologic treatment. It should be proposed to every patient at reproductive age before chemotherapy, radiotherapy or any surgery involving reproductive tract. Despite low use rate, this simple method could allow patients presenting infertility after treatment to father a child.
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Objective. Mandibular osteoradionecrosis (ORN) is a serious complication of radiotherapy (RT) in head and neck cancer patients. The aim of this study was to analyze the incidence of and risk factors for mandibular ORN in squamous cell carcinoma (SCC) of the oral cavity and oropharynx.Study Design. Case series with chart review.Setting. University tertiary care center for head and neck oncology.Subjects and Methods. Seventy-three patients treated for stage I to IV SCC of the oral cavity and oropharynx between 2000 and 2007, with a minimum follow-up of 2 years, were included in the study. Treatment modalities included both RT with curative intent and adjuvant RT following tumor surgery. The log-rank test and Cox model were used for univariate and multivariate analyses.Results. The incidence of mandibular ORN was 40% at 5 years. Using univariate analysis, the following risk factors were identified: oral cavity tumors (P < .01), bone invasion (P < .02), any surgery prior to RT (P < .04), and bone surgery (P < .0001). By multivariate analysis, mandibular surgery proved to be the most important risk factor and the only one reaching statistical significance (P < .0002).Conclusion. Mandibular ORN is a frequent long-term complication of RT for oral cavity and oropharynx cancers. Mandibular surgery before irradiation is the only independent risk factor. These aspects must be considered when planning treatment for these tumors.
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The human tyrosinase gene codes for two distinct antigens that are recognized by HLA-A*0201-restricted CTLs. For one of them, tyrosinase peptide 368-376, the sequence identified by mass spectrometry in melanoma cell eluates differs from the gene-encoded sequence as a result of posttranslational modification of amino acid residue 370 (asparagine to aspartic acid). Here, we used fluorescent tetrameric complexes ("tetramers") of HLA-A*0201 and tyrosinase peptide 368-376 (YMDGTMSQV) to characterize the CD8+ T-cell response to this antigen in lymphoid cell populations from HLA-A2 melanoma patients. Taking advantage of the presence of significant numbers of tetramer-positive CD8+ T cells in tumor-infiltrated lymph node cells from a melanoma patient, we derived polyclonal and monoclonal tyrosinase peptide 368-376-specific CTLs by tetramer-guided flow cytometric sorting. These CTLs efficiently and specifically lysed HLA-A*0201- and tyrosinase-positive melanoma cells. As assessed with tyrosinase peptide variants, the fine antigen specificity of the CTLs was quite diverse at the clonal level. Flow cytometric analysis of PBMCs stained with tetramers showed that tyrosinase peptide 368-376-specific CD8+ T cells were hardly detectable in peripheral blood of melanoma patients. However, significant numbers of such cells were detected after short-term stimulation of CD8+ lymphocytes with tyrosinase peptide 368-376 in 6 of 10 HLA-A2 melanoma patients. Taken together, these findings emphasize the significant contribution of the natural tyrosinase peptide 368-376 to the antigenic specificities recognized by the tumor-reactive CTLs that may develop in HLA-A2 melanoma patients.
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PURPOSE: To analyze final long-term survival and clinical outcomes from the randomized phase III study of sunitinib in gastrointestinal stromal tumor patients after imatinib failure; to assess correlative angiogenesis biomarkers with patient outcomes. EXPERIMENTAL DESIGN: Blinded sunitinib or placebo was given daily on a 4-week-on/2-week-off treatment schedule. Placebo-assigned patients could cross over to sunitinib at disease progression/study unblinding. Overall survival (OS) was analyzed using conventional statistical methods and the rank-preserving structural failure time (RPSFT) method to explore cross-over impact. Circulating levels of angiogenesis biomarkers were analyzed. RESULTS: In total, 243 patients were randomized to receive sunitinib and 118 to placebo, 103 of whom crossed over to open-label sunitinib. Conventional statistical analysis showed that OS converged in the sunitinib and placebo arms (median 72.7 vs. 64.9 weeks; HR, 0.876; P = 0.306) as expected, given the cross-over design. RPSFT analysis estimated median OS for placebo of 39.0 weeks (HR, 0.505, 95% CI, 0.262-1.134; P = 0.306). No new safety concerns emerged with extended sunitinib treatment. No consistent associations were found between the pharmacodynamics of angiogenesis-related plasma proteins during sunitinib treatment and clinical outcome. CONCLUSIONS: The cross-over design provided evidence of sunitinib clinical benefit based on prolonged time to tumor progression during the double-blind phase of this trial. As expected, following cross-over, there was no statistical difference in OS. RPSFT analysis modeled the absence of cross-over, estimating a substantial sunitinib OS benefit relative to placebo. Long-term sunitinib treatment was tolerated without new adverse events.
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In a mode of nude mice bearing a human colon carcinoma xenograft, the biodistribution and tumor localization of metatetrahydroxyphenylchlorin (m-THPC) coupled to polyethylene glycol (PEG) were compared with those of the free form of this photosensitizer used in photodynamic therapy (PDT). At different times after i.v. injection of both forms of 125I-labeled photosensitizer, m-THPC-PEG gave on average a 2-fold higher tumor uptake than free m-THPC. In addition, at early times after injection, m-THPC-PEG showed a 2-fold longer blood circulating half-life and a 4-fold lower liver uptake than free m-THPC. The tumor to normal tissue ratios of radioactivity concentrations were always higher for m-THPC-PEG than for free m-THPC at any time point studied from 2 to 96 hr post-injection. Significant coefficients of correlation between direct fluorescence measurements and radioactivity counting were obtained within each organ tested. Fluorescence microscopy studies showed that m-THPC-PEG was preferentially localized near the tumor vessels, whereas m-THPC was more diffusely distributed inside the tumor tissue. To verify whether m-THPC-PEG conjugate remained phototoxic in vivo, PDT experiments were performed 72 hr after injection and showed that m-THPC-PEG was as potent as free m-THPC in the induction of tumor regression provided that the irradiation does for m-THPC-PEG conjugate was adapted to a well-tolerated 2-fold higher level. The overall results demonstrate first the possibility of improving the in vivo tumor localization of a hydrophobic dye used for PDT by coupling it to PEG and second that a photosensitizer conjugated to a macromolecule can remain phototoxic in vivo.
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Bowel diseases reveal the complex interplay of sensing and signalling pathways in maintaining healthy homeostasis of the intestine. Recent studies of the xenobiotic nuclear receptor, pregnane X receptor and the inflammatory mediator nuclear transcription factor kappaB (NF-kappaB) reveal a functional link between xenobiotic neutralization and inflammation and explain how certain xenobiotics can affect the immune response. Furthermore, another nuclear receptor, peroxisome proliferator-activated receptor gamma (PPAR gamma) has been shown to produce beneficial effects in experimental inflammatory bowel diseases by repression of NF-kappaB thereby reducing inflammation, whilst its close relative PPAR beta/delta appears at a central position in signalling pathways involved in the progression of colon cancer. Recently accumulated knowledge on the action of these nuclear receptors and NF-kappaB in intestinal homeostasis may provide the rationale for the development of innovative treatment strategies with selective receptor modulators.
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Morphogens of the Wnt protein family are the secreted lipoglycoprotein ligands which initiate several pathways heavily involved in the coordination of various developmental stages of organisms in the majority of animal species. Deregulation of these pathways in the adult leads to formation and sustaining of multiple types of cancer. The latter notion is reinforced by the fact that the very discovery of the first Wnt ligand was due to its role as the causative factor of carcinogenic transformation (Nusse and Varmus, 1982). Nowadays our knowledge on Wnt signaling has "moved with the times" and these pathways were identified to be often crucial for tumor formation, its interactions with the microenvironment, and promotion of the metastases (Huang and Du, 2008; Zerlin et al., 2008; Jessen, 2009). Thus the relevance of the pathway as the target for drug development has further increased in the light of modern paradigms of the complex cancer treatments which target also spreading and growth- promoting factors of tumors by specific and highly efficient substances (Pavet et al., 2010). Presently the field of the Wnt-targeting drug research is almost solely dominated by assays based on transcriptional activation induced by the signaling. This approach resulted in development of a number of promising substances (Lee et al., 2011). Despite its effectiveness, the method nevertheless suffers from several drawbacks. Among the major ones is the fact that this approach is prone to identify compounds targeting rather downstream effectors of the pathway, which are indiscriminately used by all the subtypes of the Wnt signaling. Additionally, proteins which are involved in several signaling cascades and not just the Wnt pathway turn out as targets of the new compounds. These issues increase risks of side effects due to off-target interactions and blockade of the pathway in healthy cells. In the present work we put forward a novel biochemical approach for drug development on the Wnt pathway. It targets Frizzleds (Fzs) - a family of 7-transmbembrane proteins which serve as receptors for Wnt ligands. They offer unique properties for the development of highly specific and effective drugs as they control all branches of the Wnt signaling. Recent advances in the understanding of the roles of heterotrimeric G proteins downstream from Fzs (Katanaev et al., 2005; Liu et al., 2005; Jernigan et al., 2010) suggest application of enzymatic properties of these effectors to monitor the receptor-mediated events. We have applied this knowledge in practice and established a specific and efficient method based on utilization of a novel high-throughput format of the GTP-binding assay to follow the activation of Fzs. This type of assay is a robust and well-established technology for the research and screenings on the GPCRs (Harrison and Traynor, 2003). The conventional method of detection involves the radioactively labeled non-hydrolysable GTP analog [35S]GTPyS. Its application in the large-scale screenings is however problematic which promoted development of the novel non-radioactive GTP analog GTP-Eu. The new molecule employs phenomenon of the time-resolved fluorescence to provide sensitivity comparable to the conventional radioactive substance. Initially GTP-Eu was tested only in one of many possible types of GTP-binding assays (Frang et al., 2003). In the present work we expand these limits by demonstrating the general comparability of the novel label with the radioactive method in various types of assays. We provide a biochemical characterization of GTP-Eu interactions with heterotrimeric and small GTPases and a comparative analysis of the behavior of the new label in the assays involving heterotrimeric G protein effectors. These developments in the GTP-binding assay were then applied to monitor G protein activation by the Fz receptors. The data obtained in mammalian cultured cell lines provides for the first time an unambiguous biochemical proof for direct coupling of Fzs with G proteins. The specificity of this interaction has been confirmed by the experiments with the antagonists of Fz and by the pertussis toxin-mediated deactivation. Additionally we have identified the specificity of Wnt3a towards several members of the Fz family and analyzed the properties of human Fz-1 which was found to be the receptor coupled to the Gi/o family of G proteins. Another process playing significant role in the functioning of every GPCR is endocytosis. This phenomenon can also be employed for drug screenings on GPCRs (Bickle, 2010). In the present work we have demonstrated that Drosophila Fz receptors are involved in an unusual for many GPCRs manifestation of the receptor-mediated internalization. Through combination of biochemical approaches and studies on Drosophila as the model organism we have shown that direct interactions of the Fzs and the α-subunit of the heterotrimeric G protein Go with the small GTPase Rab5 regulate internalization of the receptor in early endosomes. We provide data uncovering the decisive role of this self-promoted endocytosis in formation of a proper signaling output in the canonical as well as planar cell polarity (PCP) pathways regulated by Fz. The results of this work thus establish a platform for the high-throughput screening to identify substances active in the cancer-related Wnt pathways. This methodology has been adjusted and applied to provide the important insights in Fz functioning and will be instrumental for further investigations on the Wnt-mediated pathways.
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BACKGROUND AND OBJECTIVE: In bladder cancer, conventional white light endoscopic examination of the bladder does not provide adequate information about the presence of "flat" urothelial lesions such as carcinoma in situ. In the present investigation, we examine a new technique for the photodetection of such lesions by the imaging of protoporphyrin IX (PpIX) fluorescence following topical application of 5-aminolevulinic acid (ALA). STUDY DESIGN/MATERIALS AND METHODS: Several hours after bladder instillation of an aqueous solution of ALA in 34 patients, a Krypton ion laser or a filtered Xenon arc-lamp was used to excite PpIX fluorescence. Tissue samples for histological analysis were taken while observing the bladder wall either by means of a video camera, or by direct endoscopic observation. RESULTS: A good correlation was found between the PpIX fluorescence and the histopathological diagnosis. On a total of 215 biopsies, 143 in fluorescent and 72 in nonfluorescent areas, all visible tumors on white light cytoscopy appeared in a bright red fluorescence with the photodetection technique. In addition, this method permitted to discover 47 unsuspected carcinomatous lesions on white light observation, among which 40% were carcinoma in situ. CONCLUSION: PpIX fluorescence induced by instillation into the bladder of 5-ALA is an efficient method of mapping the mucosa in bladder carcinoma.