Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027947 (neutropenia)
 17,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gemcitabine is an effective agent in the treatment of metastatic breast cancer. The phosphorylation of gemcitabine into the active gemcitabine triphosphate (dFdCTP) is catalyzed by deoxycytidine kinase. This enzyme is saturated at plasma concentrations achieved after an infusion over 30 min. Therefore accumulation of higher intracellular dFdCTP concentrations, which may result in an enhanced antineoplastic activity, cannot be achieved by higher dosage, but only by prolonged infusion time. The objectives of this phase I trial were to determine the dose-limiting toxicities (DLT) and the maximum tolerated dose (MTD) of gemcitabine given as a 6 h i.v. infusion. Patients with metastatic breast cancer were treated with gemcitabine as a 6 h infusion on days 1, 8 and 15 every 4 weeks. The starting dose was 200 mg/m2 with an interindividual escalation in 50 mg/m2 increments. Sixteen patients received 196 doses through three dose levels. All patients were assessable for toxicity, 13 assessable for response. The MTD was 250 mg/m2. DLT was observed at 300 mg/m2 consisting of a reversible elevation of transaminases WHO grade 3 in two patients and cutaneous toxicity grade 3 in one patient. Most common non-hematologic toxicities were mild to moderate and rapidly reversible elevation of liver enzymes in all patients, nausea and vomiting (four patients grade 2, five patients grade 3), and mild alopecia. Hematologic toxicity was mild with neutropenia WHO grade 3 and 4 in only one patient each, and no grade 3 thrombocytopenia. One patient achieved a complete remission and another patient a partial response, for an overall response rate of 15% (two of 13). In addition, seven patients (54%) had stable disease and four (31%) failed to respond to the treatment. We conclude gemcitabine 250 mg/m2 days 1, 8 and 15 every 4 weeks can be safely administered as 6 h infusion. Toxicity, especially myelosuppression, is surprisingly mild. Based on this result a phase II study with 250 mg/m2 administered over 6 h was initiated to determine the efficacy.
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PMID:Prolonged infusion of gemcitabine in stage IV breast cancer: a phase I study. 1088 99

DCK catalyzes the intracellular phosphorylation of fludarabine. The promoter and coding region of the DCK gene were analyzed in 74 follicular lymphoma (FL) patients receiving a therapeutic regimen that included fludarabine. DCK mRNA expression was quantified in a cohort of healthy donors. Four previously described genotypic variants, -360C>G, -201C>T (rs2306744), C28624T (rs11544786) and c.91+37G>C (rs9997790), as well as the new variant, -12C>G, were identified. Variant C28624T showed a lower risk of lymphopenia (P=0.04), but a higher risk of neutropenia (P=0.04). Statistical significance was found in bivariate logistic regression between lymphopenia and infectious episodes in the induction period (odds ratio 3.85, P=0.04).
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PMID:Relationship between deoxycytidine kinase (DCK) genotypic variants and fludarabine toxicity in patients with follicular lymphoma. 2105 Oct 86

Gemcitabine, an anticancer agent which acts against a wide range of solid tumors, is known to be rapidly deaminated in blood to the inactive metabolite 2',2'-difluorodeoxyuridine and to be rapidly excreted by the urine. Moreover, many cancers develop resistance against this drug, such as loss of transporters and kinases responsible for the first phosphorylation step. To increase its therapeutic levels, gemcitabine is administered at high doses (1000 mg/m(2)) causing side effects (neutropenia, nausea, and so forth). To improve its metabolic stability and cytotoxic activity and to limit the phenomena of resistance many alternatives have emerged, such as the synthesis of prodrugs. Modifying an anticancer agent is not new; paclitaxel or ara-C has been subjected to such changes. This review summarizes the various chemical modifications that can be found in the 4-(N)- and 5'-positions of gemcitabine. They can provide (i) a protection against deamination, (ii) a better storage and (iii) a prolonged release in the cell, (iv) a possible use in the case of deoxycytidine kinase deficiency, and (v) transporter deficiency. These new gemcitabine-based sysems have the potential to improve the clinical outcome of a chemotherapy strategy.
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PMID:Gemcitabine versus Modified Gemcitabine: a review of several promising chemical modifications. 2297 51

The aim of this study was to determine whether tagging polymorphisms (tSNPs) of deoxycytidine kinase (DCK) have an effect on toxicity or prognosis in patients with non-small-cell lung cancer (NSCLC) treated with gemcitabine plus cisplatin. Three tSNPs (-201 C>T, rs2306744; IVS2+9846 G>A, rs12648166; IVS6+1392 T>C, rs4694362) were chosen using the international HapMap Project and Japanese Single-Nucleotide Polymorphisms. We evaluated the associations of the tSNPs with hematologic toxicity or overall survival of 139 NSCLC patients at stages IIIA/IIIB (59) and IV (80). Hematologic toxicity such as neutropenia, thrombocytopenia, and anemia were not different by the three tSNPs or haplotypes (CGT, CAT, and CAC) of DCK. The genetic variations did not affect survival of the patients (log-rank p: 0.248 for -201 C>T, 0.571 for IVS2+9846 G>A, 0.686 for IVS6+1392 T>C, 0.556 for CGT, 0.453 for CAT, and 0.845 for CAC). In a Cox model, these tSNPs and haplotypes did not reveal prognostic relevance (aHR and 95% CI: 0.954 and 0.611 to 1.489 for -201 C>T; 1.193 and 0.719 to 1.979 for IVS2+9846 G>A; 1.072 and 0.674 to 1.706 for IVS6+1392 T>C, 0,668 and 0.205 to 2.175 for CGT, 1.043 and 0.713 to 1.525 for CAT, and 1.043 and 0.701 to 1.550 for CAC). This is the first study to focus on the association of tSNPs and their haplotypes of DCK with toxicity and survival in NSCLC patients. This suggests that genetic variations of DCK have no effect on the outcomes in the patients treated with gemcitabine-based chemotherapy.
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PMID:Lack of association of genetic variations of deoxycytidine kinase with toxicity or survival of non-small-cell lung cancer patients treated with gemcitabine plus cisplatin. 2303 62