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Yasuhiro Oki

Publications and source records attributed to Yasuhiro Oki.

10 recordsLinked to original sources
PubMed2007

Experience with heat shock protein-peptide complex 96 vaccine therapy in patients with indolent non-Hodgkin lymphoma.

BACKGROUND: The objective of this phase II trial was to investigate the safety and efficacy of autologous heat shock protein-peptide complex 96 (HSPPC-96) vaccines prepared from tumor specimens of patients with newly diagnosed or previously treated indolent non-Hodgkin lymphoma (NHL). METHODS: The study was for patients with indolent B-cell NHL with measurable lesions. HSPPC-96 vaccines were prepared from patients' resected tumor specimens and administered as a 25-microg intradermal injection in the absence of disease progression every week for 4 weeks and then every 2 weeks until the vaccine supply was exhausted. RESULTS: Twenty patients were enrolled in this trial. The median patient age was 59 years. Ten patients had been treated previously (median, 2 regimens; range, 1 to 7). Eighteen (90%) patients had stage III or IV disease. Autologous vaccines were successfully prepared for 17 (85%) patients and all received at least 1 dose. The treatment was very well tolerated. One patient experienced a response with biopsy-proven clearance of the lymphoma cells in 2 of the skin nodules at 3.0 months that lasted for 7.0 months. Eight patients had stable disease for 6.0 to 19.8 months. The median failure-free survival duration in patients who received vaccine therapy was 5.2 months. CONCLUSIONS: HSPPC-96 can be prepared from tumor specimens for the majority of lymphoma patients, but it had limited efficacy in inducing responses in patients with active diseases. Further studies of HSPPCs, therefore, should be considered in adjuvant settings or in combination with other immunomodulatory agents to assess survival benefit.

Aged↗
PubMed2006

Decitabine--bedside to bench.

PURPOSE OF THE REVIEW: Epigenetic changes marked by DNA methylation are known to contribute to the malignant transformation of cells by silencing critical genes. Decitabine inhibits DNA methyltransferase and has shown therapeutic effects in patients with hematologic malignancies. However, the connection between the clinical activity of decitabine and its demethylating activity is not clear. Herein, we summarize the results of recent clinical trials of decitabine in hematologic malignancies, and review the translational research into decitabine's mechanism of clinical activity. RECENT FINDINGS: Low-dose decitabine has been studied recently in multiple clinical trials and has been shown to be effective for treatment of myelodysplastic syndromes. Correlative laboratory studies of clinical trials have shown that decitabine induces global hypomethylation as well as hypomethylation of gene-specific promoters and activation of gene expression. Past a given threshold, induction of higher degrees of hypomethylation is not directly associated with a better clinical outcome. Moreover, studies have suggested that patients with promoter hypermethylation of p15(INK4B) at baseline have paradoxically a lower chance of achieving response than those without hypermethylation. Furthermore, several other genes activated by decitabine were independent of hypomethylation in the promoter regions. CONCLUSION: While at least part of decitabine's activity is through induction of hypomethylation and reactivation of critical genes, mechanisms independent from hypomethylation are also important for decitabine's antitumor activity.

Antimetabolites, Antineoplastic↗
PubMed2006

Results of a randomized study of 3 schedules of low-dose decitabine in higher-risk myelodysplastic syndrome and chronic myelomonocytic leukemia.

Epigenetic therapy with hypomethylating drugs is now the standard of care in myelodysplastic syndrome (MDS). Response rates remain low, and mechanism-based dose optimization has not been reported. We investigated the clinical and pharmacodynamic results of different dose schedules of decitabine. Adults with advanced MDS or chronic myelomonocytic leukemia (CMML) were randomized to 1 of 3 decitabine schedules: (1) 20 mg/m2 intravenously daily for 5 days; (2) 20 mg/m2 subcutaneously daily for 5 days; and (3) 10 mg/m2 intravenously daily for 10 days. Randomization followed a Bayesian adaptive design. Ninety-five patients were treated (77 with MDS, and 18 with CMML). Overall, 32 patients (34%) achieved a complete response (CR), and 69 (73%) had an objective response by the new modified International Working Group criteria. The 5-day intravenous schedule, which had the highest dose-intensity, was selected as optimal; the CR rate in that arm was 39%, compared with 21% in the 5-day subcutaneous arm and 24% in the 10-day intravenous arm (P < .05). The high dose-intensity arm was also superior at inducing hypomethylation at day 5 and at activating P15 expression at days 12 or 28 after therapy. We conclude that a low-dose, dose-intensity schedule of decitabine optimizes epigenetic modulation and clinical responses in MDS.

Aged↗
PubMed2006

Mutations and promoter methylation status of NPM1 in myeloproliferative disorders.

We determined mutations and promoter methylation status of NPM1 using pyrosequencing in 199 samples of myeloid neoplasia including myeloproliferative disorders (MPD). The mutations were present in 4% of chronic myelomonocytic leukemia, but not in other MPD or myelodysplastic syndromes. Promoter methylation was rare, and was found in only three samples of MPD.

Base Sequence↗
PubMed2006

Silencing of bidirectional promoters by DNA methylation in tumorigenesis.

CpG island methylation within promoters is known to silence individual genes in cancer. The involvement of this process in silencing gene pairs controlled by bidirectional promoters is unclear. In a screen for hypermethylated CpG islands in cancer, bidirectional promoters constituted 25.2% of all identified promoters, which matches with the genomic representation of bidirectional promoters. From the screen, we selected three bidirectional gene pairs for detailed analysis, WNT9A/CD558500, CTDSPL/BC040563, and KCNK15/BF195580. Levels of mRNA of all three pairs of genes were inversely correlated with the degree of promoter methylation in multiple cancer cell lines. Hypomethylation of these promoters induced by 5-aza-2'-deoxycytidine treatment reactivated or enhanced gene expression bidirectionally. The bidirectional nature of the WNT9A/CD558500 promoter was confirmed by luciferase assays, and hypermethylation down-regulated expression of both genes in the pair. Methylation of WNT9A/CD558500 and CTDSPL/BC040563 promoters occurs frequently in primary colon cancers and acute lymphoid leukemias (ALL), respectively, and methylation was correlated with decreased gene expression in ALL patient samples. Our study shows that hypermethylation of bidirectional promoter-associated CpG island silences two genes simultaneously, a property that should be taken into account when studying the functional consequences of hypermethylation in cancer.

Cell Line, Tumor↗
PubMed2005

Adult acute megakaryocytic leukemia: an analysis of 37 patients treated at M.D. Anderson Cancer Center.

To characterize acute megakaryocytic leukemia (FAB M7 AML), we identified 37 patients with M7 AML treated at M.D. Anderson Cancer Center between 1987 and 2003 and compared them with 1800 patients with non-M7, non-M3 AML treated during the same period. The median age of the M7 AML group was 56 years (range, 21-78 years); 22 patients (59%) had an antecedent hematologic disorder or myelodysplastic syndrome or both, and 7 patients (19%) had previously received chemotherapy for other malignancies. Extensive bone marrow fibrosis was found in 23 patients (62%). Poor cytogenetic characteristics were observed in 49% of patients with M7 AML versus 33% of others (P < .001). Complete remission rates were 43% with M7 AML and 57% with non-M7 AML (P = .089). Median overall survival (OS) was 23 and 38 weeks, respectively (P = .006). Median disease-free survivals were 23 versus 52 weeks, respectively (P < .001). By multivariate analysis, M7 AML was an independent adverse prognostic factor for OS, independent of other factors including cytogenetic abnormalities (hazard ratio 1.51, P = .049). These results confirm the poor prognosis of M7 AML and indicate that other biologic characteristics beyond cytogenetic abnormalities likely play a role in this disease.

Adult↗
PubMed2005

Phase II study of oxaliplatin in patients with recurrent or refractory non-Hodgkin lymphoma.

BACKGROUND: Oxaliplatin is a platinum derivative with a broad range of anticancer activity. The objective of the current Phase II trial was to investigate the activity of oxaliplatin in patients with recurrent or refractory non-Hodgkin lymphoma (NHL). METHODS: Patients with recurrent and refractory NHL who received a maximum of 3 previous chemotherapy regimens were considered eligible if they had an Eastern Cooperative Oncology Group performance status of 0-2 and adequate organ function. Oxaliplatin was administered in an outpatient setting at a dose of 130 mg/m(2) by 2-hour intravenous infusion every 21 days for < or = 6 cycles in the absence of disease progression. RESULTS: Thirty-one patients (23 with aggressive NHL and 8 with indolent NHL) were enrolled, of whom 30 were assessable for toxicity, response, and survival. The median patient age was 62 years, and 20% of the patients previously received platinum-containing therapy. Eighty-three percent of the patients were refractory to their last treatment regimens. Grade 3 and 4 toxic effects (according to the National Cancer Institute's Common Toxicity Criteria [version 2.0]) included sensory neuropathy (10%), neutropenia (17%), and thrombocytopenia (20%). Objective responses occurred in 8 (27%; 95% confidence interval, 13-47%) of the patients. Responses were observed in platinum-naive patients as well as in those previously treated with platinum. The overall median failure-free survival duration was 3.0 months (range, 0.1-18.1 months). CONCLUSIONS: Oxaliplatin had favorable single-agent activity in previously treated patients with refractory lymphoma. The favorable safety profile and the ease of its administration in outpatient settings warrant investigating it in combination with other active drugs for the treatment of recurrent and refractory NHL.

Adult↗
PubMed2005

JAK2 mutation 1849G>T is rare in acute leukemias but can be found in CMML, Philadelphia chromosome-negative CML, and megakaryocytic leukemia.

An activating 1849G>T mutation of JAK2 (Janus kinase 2) tyrosine kinase was recently described in chronic myeloproliferative disorders (MPDs). Its role in other hematologic neoplasms is unclear. We developed a quantitative pyrosequencing assay and analyzed 374 samples of hematologic neoplasms. The mutation was frequent in polycythemia vera (PV) (86%) and myelofibrosis (95%) but less prevalent in acute myeloid leukemia (AML) with an antecedent PV or myelofibrosis (5 [36%] of 14 patients). JAK2 mutation was also detected in 3 (19%) of 16 patients with Philadelphia-chromosome (Ph)-negative chronic myelogenous leukemia (CML), 2 (18%) of 11 patients with megakaryocytic AML, 7 (13%) of 52 patients with chronic myelomonocytic leukemia, and 1 (1%) of 68 patients with myelodysplastic syndromes. No mutation was found in Ph(+)CML (99 patients), AML M0-M6 (28 patients), or acute lymphoblastic leukemia (20 patients). We conclude that the JAK2 1849G>T mutation is common in Ph(-) MPD but not critical for transformation to the acute phase of these diseases and that it is generally rare in aggressive leukemias.

Humans↗
PubMed2004

Heat shock protein-based cancer vaccines.

Heat shock proteins (HSPs) exist ubiquitously across all species and function as chaperones stabilizing and delivering peptides. Tumor-derived HSP-peptide complex has been known to induce immunity against the original tumor in preclinical studies. HSP-based vaccines work across tumor types and bypass the need for identifying the responsible peptide(s) for inducing immunity. These vaccines are tumor- and patient-specific in that they capture the tumor cells' fingerprints. HSP-based vaccines have been studied in early phase clinical trials, mostly using HSP glycoprotein 96, for various types of malignancies including melanoma, renal cell carcinoma, gastric cancer, pancreatic cancer, low-grade lymphoma, colorectal cancer and chronic myelogenous leukemia. All showed minimal toxicity and potential efficacy. Phase III studies for melanoma and renal cell carcinoma are ongoing. HSP-based vaccines are a novel vaccine preparation with a promising role in cancer management. Further studies to determine the administering strategy and specific indication are warranted.

Animals↗