Clin Cancer Res
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Multicenter Study Clinical Trial
Clinical trial substantiates the predictive value of O-6-methylguanine-DNA methyltransferase promoter methylation in glioblastoma patients treated with temozolomide.
In the setting of a prospective clinical trial, we determined the predictive value of the methylation status of the O-6-methylguanine-DNA methyltransferase (MGMT) promoter for outcome in glioblastoma patients treated with the alkylating agent temozolomide. Expression of this excision repair enzyme has been associated with resistance to alkylating chemotherapy. ⋯ This prospective clinical trial identifies MGMT-methylation status as an independent predictor for glioblastoma patients treated with a methylating agent. The association of the epigenetic inactivation of the DNA repair gene MGMT with better outcome in this homogenous cohort may have important implications for the design of future trials and supports efforts to deplete MGMT by O-6-benzylguanine, a noncytotoxic substrate of this enzyme.
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The purpose is to determine the plasma pharmacokinetics, the maximum-tolerable dose and to preliminary evaluate the antitumor activity of irinotecan administered as a 7-day continuous infusion every 21 days in metastatic colorectal cancer patients pretreated with 5-fluorouracil or raltitrexed. ⋯ The administration of irinotecan as a 7-day continuous infusion every 21 days is feasible with diarrhea being the dose-limiting toxicity; recommended dose for Phase II studies is 20.0 mg/m(2)/day. The comparison of the present data with those obtained after a standard 30-90 min. i.v. infusion of irinotecan demonstrates that continuous infusion improves the transformation of irinotecan to SN-38 and also results in increased glucuronidation of the active metabolite. Antitumor activity in pretreated metastatic colorectal cancer patients is encouraging.
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The majority of cases of Cushing's disease are due to the presence of a corticotroph microadenoma. Less frequently no adenoma is found and histology shows either corticotroph hyperplasia, or apparently normal pituitary. In this study we have used molecular pathology to determine whether the tissue labeled histologically as "normal" is indeed abnormal. ⋯ To our knowledge this is the first report that describes an intrinsic molecular change, namely methylation of the p16 gene CpG island, common to all three histological patterns associated with Cushing's disease. Thus, the use of molecular pathology reveals abnormalities undetected by routine pathological investigation. In cases of "apparently" normal pituitaries it is not possible to determine whether the change is associated with adenoma cells "scattered" throughout the gland, albeit few in number, or with the ancestor-clonal origin of these tumor cells.