Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cholangiocarcinomas (CCC) are rare tumors with an incidence of 2-4/100,000 per year. They are a heterogeneous group of neoplasias that include the most common perihilar or Klatskin tumor (60%), the intrahepatic (peripheral) CCC, the extrahepatic bile duct cancer, the gallbladder cancer and the cancer of the ampulla of Vater. At the time of diagnosis only 20% of patients can be treated by surgery, that offers the only chance for cure. Due to high recurrence rates liver transplantation is not indicated. Patients with advanced unresectable carcinoma have a dismal prognosis with an overall survival rate of only 6-8 months. Neither chemotherapy nor radiation therapy improves survival. In patients not eligible for curative surgery prevention or treatment of cholestatis is the main objective. This can be achieved endoscopically, percutaneously or by surgical biliodigestive anastomosis. Palliative chemotherapy results in response rates up to 20%. The most frequently used agents are 5-FU and Gemcitabine that can be combined with external or internal radiation. By combining different treatment modalities significant survival can be achieved in some patients. Evidence Based Medicine studies are needed before treatment strategies can be recommended for clinical practice.
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PMID:[Cholangiocarcinoma]. 1223 66

Gemcitabine is a cytotoxic nucleoside analog with activity in relapsing/refractory Hodgkin's disease (HD). Because gemcitabine is hydrophilic, it requires plasma membrane nucleoside transporter proteins to access intracellular targets. The most abundant and widely distributed transporter in human cells is human equilibrative nucleoside transporter 1 (hENT1). Because our prior studies showed that a deficiency in hENT1 confers high-level resistance to gemcitabine toxicity in vitro, we developed an immunohistochemical method to assess the hENT1 abundance of cells in tumor tissue. We now report the application of this method for visualizing the hENT1 protein abundance in the plasma membranes of Reed-Sternberg cells in lymph nodes of HD patients. Frozen sections of 30 lymph nodes were stained with monoclonal antibodies (mAb 10D7G2) raised against a synthetic peptide comprised of residues 254-271 from the large intracellular loop of hENT1 and staining intensity was scored on a 0-4 + scale. hENT1-staining intensity varied among HD lymph node samples (score/n; 0/8; 1/10; 2/9; 3/3; 4/0) and suggested that at least 60% of the tumors appeared hENT1 deficient. Because Epstein-Barr virus (EBV) is often associated with HD, staining for Epstein-Barr early RNA was also examined. Although 9/30 patients tested positive for EBV, there was no correlation with hENT1 staining. hENT1-staining intensities were positively correlated with age of the patient but were independent of other clinical, laboratory or pathology features (tumor stage, histologic subtype, presence of B symptoms, staining for CD15 or CD30, serum biochemistry, disease free survival, and overall survival). We conclude that, because hENT1 deficiency has been previously related to nucleoside-drug resistance, immunohistochemical staining for hENT1 warrants evaluation as a predictive tool for guiding the appropriate use of gemcitabine in the treatment of HD.
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PMID:Differential expression of human equilibrative nucleoside transporter 1 (hENT1) protein in the Reed-Sternberg cells of Hodgkin's disease. 1238 26

Preclinical studies in our laboratory have demonstrated that prior exposure to hydroxyurea increases the percentage of cells in S phase, enhancing the cytotoxicity of subsequent gemcitabine treatment in human oropharyngeal KB cells. To evaluate the clinical implications of this time- and sequence-dependent potentiation, we performed a phase I trial of hydroxyurea given over 24 h followed by a 30-min infusion of gemcitabine in weeks 1 and 2 of a 3-week cycle. The dose of hydroxyurea was fixed at 500 mg orally every 6 h for four doses starting 24 h before each dose of gemcitabine. The initial dose level of gemcitabine was 250 mg/m(2) on days 2 and 9, and this was escalated stepwise to 1000 mg/m(2) on days 2 and 9. Gemcitabine pharmacokinetics were determined on days 2 and 9 of the first cycle. Of 27 patients enrolled (12 female, 15 male), 24 were evaluable for response and 23 were evaluable for toxicity. Their median age was 56 years (range 27-76 years). Tumor types included lung, head and neck, pancreas, breast, colon, prostate, stomach, ovary, esophagus, germ cell, thyroid, gallbladder, and unknown primary. A total of 80 cycles of treatment were completed. One patient (unknown primary) had an objective partial response lasting 21 months, and 12 patients had stable disease. All observed dose-limiting toxicities were related to myelosuppression. The gemcitabine maximum tolerated dose was established at 750 mg/m(2) on days 2 and 9. Hydroxyurea had no effect on the plasma pharmacokinetics of gemcitabine. These results suggest that hydroxyurea followed by gemcitabine can be safely administered and has activity on this schedule. We are presently developing a phase II trial of this regimen for patients with platinum-resistant head and neck cancer.
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PMID:Phase I pharmacodynamic study of time and sequence dependency of hydroxyurea in combination with gemcitabine: a California Cancer Consortium Trial. 1243 92

Gemcitabine has demonstrated a good efficacy in number of tumor types. Thanks to its favourable toxicity profile, gemcitabine can be used in combination with a number of drugs. Single agent gemcitabine and gemcitabine-based combinations have been evaluated in metastatic breast cancer. Some of these combinations, such as gemcitabine-vinorelbine, seem highly efficacious in patients with taxane and/or anthracycline refractory disease. Other combinations such as gemcitabine-anthracycline-taxane regimens were found to be highly effective in the neoadjuvant setting or as first line treatment for metastatic breast cancer. Some of the combinations tested deserve further evaluation in phase III trials. Several phase III trials are in progress in Europe and in the USA. Final judgment on the contribution of gemcitabine will not be made until the results of these further studies become available.
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PMID:[Gemcitabine and breast cancer]. 1244 40

Gemcitabine is a molecule presenting with major radiosensitizing or radio-potentiator capacities. This property has been extensively studied in vitro, with clinical therapeutic implications. Chemotherapy and radiation are very often used together, most of the time concurrently. This review analyses the results obtained with combined gemcitabine and radiation, for non small cell lung cancer, pancreatic adenocarcinoma, head and neck and uterine cervix carcinomas. Several therapeutic schemes are presented, for each tumor location. A description of the toxicities observed is presented, including the recall phenomenon description. Promising results justify the numerous current trials, as well as enthusiasm initiated by this therapeutic association.
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PMID:[Combined gemcitabine and radiotherapy]. 1244 44

The efficacy of gemcitabine containing regimens has been explored in a large number of studies presented at ASCO 2002. The activity of gemcitabine-platinum based combinations was confirmed in lung cancer and bladder cancer. In pancreatic cancer, single agent gemcitabine remains the reference treatment, but newer combinations with oxaliplatin or docetaxel show promising activity in phase II trials and are currently being evaluated in phase III. Gemcitabine has demonstrated promising activity in phase II studies in metastatic breast cancer and gynaecologic tumors; phase III trials are ongoing. Concomitant chemo-radiation using gemcitabine as a radiosensitizer have been shown to be highly effective in pancreatic and in bladder cancer and deserve further investigation. The growing interest in gemcitabine-based combinations in various tumor types together with the results presented at ASCO 2002 confirm the broad range of activity of this drug. This is a review of papers presented at ASCO 2002.
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PMID:[Updates on gemcitabine at the American Society of Clinical Oncology congress (ASCO, 2002) ]. 1244 45

Deoxycytidine kinase (dCK) is essential for the phosphorylation of gemcitabine (2',2'-difluorodeoxycytidine), a deoxycytidine analogue active against various solid tumors. Cytidine deaminase (CDA) catalyzes the degradation of gemcitabine. We determined whether dCK and/or CDA levels would predict response to gemcitabine. Activities of dCK and CDA were measured in a panel of eight gemcitabine-sensitive and -resistant tumors of a different origin (pancreas, lung, colon, ovary, and head and neck) grown as s.c. tumors in mice. Sensitivity to gemcitabine was expressed as treated versus control (tumor volume treated mice/control mice). Gemcitabine was given on days 0, 3, 6, and 9 (q3dx4) at its maximum tolerated dose. In addition, we measured the mRNA expression and protein levels of dCK in seven human tumor xenografts. dCK activity (mean +/- SE) ranged from 3.3+/-0.3 to 18.4+/-1.2 nmol/h/mg protein. Sensitivity to gemcitabine, expressed as treated versus control, ranged from 0.98 to 0.02, and the activity of CDA varied from 2+/-2 to 411+/-4 nmol/h/mg protein. In contrast to CDA, dCK activity was clearly related to gemcitabine sensitivity (p = -0.93; P < 0.001). This indicates that dCK might be an important prognostic marker for gemcitabine sensitivity. Protein levels were significantly related to both dCK activity (r = 0.96; P < 0.001) and gemcitabine sensitivity (rho = -0.96; P < 0.001). dCK expression as determined by competitive template reverse transcriptase PCR was significantly related with the dCK activity (r = 0.88; P = 0.025) and protein levels (p = 0.80; P = 0.052) but not with gemcitabine sensitivity, suggesting a post-translational regulation of dCK. In conclusion, the clear correlation between dCK levels and gemcitabine sensitivity in various murine tumors and human tumor xenografts may be a prognostic parameter when considering gemcitabine therapy.
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PMID:Pretreatment deoxycytidine kinase levels predict in vivo gemcitabine sensitivity. 1247 49

Pancreatic cancer is the fifth leading cause of cancer death in North America. Gemcitabine improves the quality of life of patients but fails to significantly reduce mortality. Our laboratory has demonstrated previously that the phosphatidylinositol 3'-kinase inhibitor wortmannin promotes gemcitabine antitumor activity (S. S. W. Ng et al., Clin. Cancer Res., 7: 3269-3275, 2001). The present study examined the effects of the epidermal growth factor receptor (EGFR) inhibitor OSI-774 ("Tarceva") alone and in combination with wortmannin and/or gemcitabine on downstream signaling molecules, as well as apoptosis in primary pancreatic cancer xenografts implanted orthotopically in severely combined immunodeficient mice. Tumors established from two pancreatic cancer patients [Ontario Cancer Institute Pancreas number (OCIP#) 2 and OCIP#7] were treated with various combinations of the above three drugs and harvested for analyses of the following: the levels of phosphorylated and nonphosphorylated forms of EGFR, protein kinase B (PKB/Akt) and extracellular-regulated kinase (ERK1/2), and the extent of apoptosis using immunofluorescence image analysis and TUNEL assay, respectively. OSI-774 alone significantly inhibited phosphorylation of EGFR in both of the primary xenografts. Phosphorylation of pERK decreased in OCIP#2, but not in OCIP#7. No significant effects on pPKB because of OSI-774 were observed in either tumor type. The extent of apoptosis was significantly increased by 2-fold in OCIP#2 tumors treated with gemcitabine and wortmannin in combination; an additional 2-fold increase in apoptosis was evident in the presence of OSI-774. Although wortmannin failed to enhance gemcitabine-induced apoptosis in OCIP#7 tumors, the extent of apoptosis was significantly increased with the inclusion of OSI-774 in the combination. Taken together, these findings support the use of OSI-774 plus a phosphatidylinositol 3'-kinase inhibitor in combination with gemcitabine in the treatment of pancreatic cancer.
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PMID:Effects of the epidermal growth factor receptor inhibitor OSI-774, Tarceva, on downstream signaling pathways and apoptosis in human pancreatic adenocarcinoma. 1249 10

Induction chemotherapy followed by surgery, particularly with newer agents or combinations, remains to be explored in locally advanced cervical cancer. Gemcitabine cisplatin is a very active combination for this tumor, therefore we explored the activity of gemcitabine in combination with oxaliplatin. Ten untreated patients with histologic diagnosis of cervical carcinoma and staged as IB2 to IIIB were treated with 3 21-day courses of oxaliplatin 130 mg/m day 1 and gemcitabine 1,250 mg/m days 1 and 8 followed by locoregional treatment with either surgery or concomitant chemoradiation. Response and toxicity were evaluated at the end of chemotherapy. All patients were evaluable. The overall clinical response rate was 80%, being complete in 3 patients (30%) and partial in 5 (50%). Seven (70%) patients underwent surgery, and three (30%) had chemoradiation as definitive treatment. Hematologic toxicity was moderate, with leukopenia grades III-IV in 17 and 0%; granulocytopenia grades III-IV in 23 and 3%, respectively. Eight patients had grade I oropharyngeal toxicity. At a median follow-up of 11 months (range: 10-12), all patients are disease free. Gemcitabine oxaliplatin is a very active and well-tolerated combination for locally advanced cervical cancer.
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PMID:Induction chemotherapy with gemcitabine and oxaliplatin for locally advanced cervical carcinoma. 1257 19

Cancers of the biliary tract are rare, and remain a major challenge to surgical, medical, and radiation oncologists. Unfortunately, the large majority of these tumors are not resectable at the time of initial diagnosis, and patients with advanced disease face a dismal prognosis. The efficacy of conventional palliative systemic chemotherapy (eg, with 5-fluorouracil, mitomycin-C, and cisplatin) seems negligible, and there is presently no agreement on the best chemotherapeutic regimen. Gemcitabine is among several different new anticancer drugs under investigation in the treatment of advanced biliary tract cancer. Apart from its favorable toxicity profile, this novel nucleoside analog has shown activity in many solid tumors, including pancreatic adenocarcinoma. In view of the histogenetic affinity between the pancreas and the biliary tract, and several case reports describing the efficacy of gemcitabine in advanced gallbladder or cholangiocellular carcinoma, a number of phase II investigations have been undertaken. In the majority of these trials a conventional gemcitabine dose regimen of 1,000 to 1,200 mg/m(2) given over 30 minutes on 3 consecutive weeks followed by a week of rest has been used. In a total of seven studies involving 167 assessable patients, objective response rates up to 60% (36% in the largest trial composed of 39 evaluable patients), abrogation of progressive disease (complete response + partial response + stable disease) in 50% to 93%, and overall survival times ranging from 6.3 to 16 months, have been reported. The consensus is that the tolerance of treatment was remarkable with only exceptional patients (< or = 5%) experiencing grade 4 hematologic toxicities. Nonhematologic side effects were infrequent and almost exclusively mild to moderate. In three of the trials, a formal clinical benefit analysis was included, suggesting that a considerable proportion of symptomatic patients will experience relief of tumor-related symptoms and/or weight gain. Possible options currently being investigated to further improve the therapeutic results of gemcitabine monotherapy include modifications of the dose regimen as well as combinations with other potentially synergistic anticancer drugs. In the latter approach, preliminary data have been reported for gemcitabine plus cisplatin, oxaliplatin, docetaxel, mitomycin-C, and continuous-infusion 5-fluorouracil/leucovorin. Objective response rates as high as 53% (for gemcitabine/cisplatin), and median survival times > or = 11 months with only a slight increase in frequency and severity of side effects have been reported. In conclusion, while the best available chemotherapeutic treatment for advanced biliary tract cancer remains to be determined, accumulating data from recent phase II trials suggest that single-agent gemcitabine represents an active and very well-tolerated treatment option. It may also be safely combined with other drugs, though further improvements in response activity and survival warrant confirmation in future randomized studies.
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PMID:Review of gemcitabine in biliary tract carcinoma. 1257 32


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