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Dive into the research topics where Masataka Okamoto is active.

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Featured researches published by Masataka Okamoto.


Leukemia | 2009

Clinical features and prognosis of de novo diffuse large B-cell lymphoma with t(14;18) and 8q24 /c-MYC translocations

Nozomi Niitsu; Masataka Okamoto; Ikuo Miura; Masami Hirano

Diffuse large B-cell lymphoma (DLBCL) having both t(14;18) and 8q24 translocations is rare. We evaluated the clinical characteristics and prognoses of patients with DLBCL carrying both t(14;18) and 8q24 translocations. A total of 1972 patients with non-Hodgkins lymphoma were treated in the Adult Lymphoma Treatment Study Group (ALTSG) from 1998 to 2007. Nineteen cases of de novo DLBCL with the dual translocation were identified. The dual translocation was observed in 19 of 394 patients with DLBCL (10 males and 9 females, with a median age of 61 years). The dual translocation was observed significantly more frequently among patients with high lactate dehydrogenase levels, B symptoms, bone marrow involvement and advanced stage. Immunophenotyping was performed and showed DLBCL with a germinal center type in the majority of cases. Progression-free survival and overall survival rates were significantly lower in patients with the dual translocation than in those with other translocation. DLBCL patients with concurrent t(14;18) and 8q24 translocations have very poor prognosis. Even if patients had a complete response to chemotherapy, they subsequently suffered early relapse. In this study, only a few patients received rituximab, and its usefulness could not be assessed. Future studies with larger numbers of patients are required.


Journal of Clinical Oncology | 2008

Retrospective Analysis of Intravascular Large B-Cell Lymphoma Treated With Rituximab-Containing Chemotherapy As Reported by the IVL Study Group in Japan

Kazuyuki Shimada; Kosei Matsue; Kazuhito Yamamoto; Takuhei Murase; Naoaki Ichikawa; Masataka Okamoto; Nozomi Niitsu; Hiroshi Kosugi; Norifumi Tsukamoto; Hiroshi Miwa; Hideki Asaoku; Ako Kikuchi; Morio Matsumoto; Yoshio Saburi; Yasufumi Masaki; Motoko Yamaguchi; Shigeo Nakamura; Tomoki Naoe; Tomohiro Kinoshita

PURPOSE To evaluate the safety and efficacy of rituximab-containing chemotherapies for intravascular large B-cell lymphoma (IVLBCL). PATIENTS AND METHODS We retrospectively analyzed 106 patients (59 men, 47 women) with IVLBCL who received chemotherapy either with rituximab (R-chemotherapy, n = 49) or without rituximab (chemotherapy, n = 57) between 1994 and 2007 in Japan. The median patient age was 67 years (range, 34 to 84 years). The International Prognostic Index was high-intermediate/high in 97% of patients. RESULTS The complete response rate was higher for patients in the R-chemotherapy group (82%) than for those in the chemotherapy group (51%; P = .001). The median duration of follow-up for surviving patients was 18 months (range, 1 to 95 months). Progression-free survival (PFS) and overall survival (OS) rates at 2 years after diagnosis were significantly higher for patients in the R-chemotherapy group (PFS, 56%; OS, 66%) than for patients in the chemotherapy group (PFS, 27% with P = .001; OS, 46% with P = 0.01). Multivariate analysis revealed that the use of rituximab was favorably associated with PFS (hazard ratio [HR], 0.45; 95% CI, 0.25 to 0.80; P = .006) and OS (HR, 0.42; 95% CI, 0.21 to 0.85; P = .016). Treatment-related death was observed in three patients (6%) who received R-chemotherapy and in five patients (9%) who received chemotherapy. CONCLUSION Our data suggest improved clinical outcomes for patients with IVLBCL in the rituximab era. Future prospective studies of rituximab-containing chemotherapies are warranted.


Blood | 2010

Hepatic toxicity and prognosis in hepatitis C virus–infected patients with diffuse large B-cell lymphoma treated with rituximab-containing chemotherapy regimens: a Japanese multicenter analysis

Daisuke Ennishi; Yoshinobu Maeda; Nozomi Niitsu; Minoru Kojima; Koji Izutsu; Jun Takizawa; Shigeru Kusumoto; Masataka Okamoto; Masahiro Yokoyama; Yasushi Takamatsu; Kazutaka Sunami; Akira Miyata; Kayoko Murayama; Akira Sakai; Morio Matsumoto; Katsuji Shinagawa; Akinobu Takaki; Keitaro Matsuo; Tomohiro Kinoshita; Mitsune Tanimoto

The influence of hepatitis C virus (HCV) infection on prognosis and hepatic toxicity in patients with diffuse large B-cell lymphoma in the rituximab era is unclear. Thus, we analyzed 553 patients, 131 of whom were HCV-positive and 422 of whom were HCV-negative, with DLBCL treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (RCHOP)-like chemotherapy. Survival outcomes and hepatic toxicity were compared according to HCV infection. The median follow-up was 31 and 32 months for patients who were HCV-positive and HCV-negative, respectively. HCV infection was not a significant risk factor for prognosis (3-year progression-free survival, 69% vs 77%, P = .22; overall survival, 75% vs 84%, P = .07). Of 131 patients who were HCV-positive, 36 (27%) had severe hepatic toxicity (grade 3-4), compared with 13 of 422 (3%) patients who were HCV-negative. Multivariate analysis revealed that HCV infection was a significant risk factor for severe hepatic toxicity (hazard ratio: 14.72; 95% confidence interval, 6.37-34.03; P < .001). An exploratory analysis revealed that pretreatment transaminase was predictive of severe hepatic toxicity. HCV-RNA levels significantly increased during immunochemotherapy (P = .006). These results suggest that careful monitoring of hepatic function and viral load is indicated during immunochemotherapy for HCV-positive patients.


Blood | 2011

Prospective measurement of Epstein-Barr virus-DNA in plasma and peripheral blood mononuclear cells of extranodal NK/T-cell lymphoma, nasal type

Ritsuro Suzuki; Motoko Yamaguchi; Koji Izutsu; Go Yamamoto; Kenzo Takada; Yasuaki Harabuchi; Yasushi Isobe; Hiroshi Gomyo; Tadashi Koike; Masataka Okamoto; Rie Hyo; Junji Suzumiya; Shigeo Nakamura; Keisei Kawa; Kazuo Oshimi

Epstein-Barr virus (EBV)-DNA was prospectively analyzed in plasma and mononuclear cells (MNCs) from peripheral blood in patients with extranodal natural killer (NK)/T-cell lymphoma, nasal type, to evaluate the clinical significance for diagnosis, monitoring the tumor burden, and prognostication. Thirty-three patients were enrolled, and 32 were evaluable. Pretreatment plasma and MNC EBV-DNA was detectable in 14 (range, 50-71 000 copies/mL) and 6 patients (range, 20-780 copies/μg DNA), respectively, and both were well correlated (r = 0.8741, P < .0001). Detectable plasma EBV-DNA was associated with higher clinical stage (P = .02), presence of B symptoms (P = .02), worse performance status (P = .02), and higher serum soluble IL-2 receptor level (P < .0001). Twenty-two patients attained complete response. Plasma EBV-DNA level was significantly higher in nonresponders than in responders (mean, 16,472 vs 2,645 copies/mL; P = .02). Multivariate analysis showed clinical stage (hazard ratio, 9.0; 95% confidence interval, 1.8%-45.0%) and pretreatment plasma EBV-DNA (hazard ratio, 10.6; 95% confidence interval, 1.3%-87.0%) were significant prognostic factors. Three-year overall survival of plasma EBV-DNA positive and negative patients was 42.9% and 94.4%, respectively (P = .0009). Plasma was a preferable sample for this purpose in NK/T-cell lymphoma, nasal type, and EBV-DNA level was a good indicator for response and overall survival.


Haematologica | 2008

De novo CD5+ diffuse large B-cell lymphoma: results of a detailed clinicopathological review in 120 patients

Motoko Yamaguchi; Naoya Nakamura; Ritsuro Suzuki; Yoshitoyo Kagami; Masataka Okamoto; Ryo Ichinohasama; Tadashi Yoshino; Junji Suzumiya; Takuhei Murase; Ikuo Miura; Koichi Ohshima; Momoko Nishikori; Jun-ichi Tamaru; Masafumi Taniwaki; Masami Hirano; Yasuo Morishima; Ryuzo Ueda; Hiroshi Shiku; Shigeo Nakamura

Diffuse large B-cell lymphoma (DLBCL) constitutes the largest category of aggressive lymphomas, and is considered to have heterogeneous biological properties. De novo CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is a distinct entity. This study reveals the morphological spectrum of CD5+ DLBCL, shows that the incidence of central nervous system recurrence in this form of lymphoma in high, and confirms that CD5+ DLBCL frequently expresses BCL2 protein. Background De novo CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is clinicopathologically and genetically distinct from CD5-negative (CD5−) DLBCL and mantle cell lymphoma. The aim of this retrospective study was to clarify the histopathological spectrum and obtain new information on the therapeutic implications of CD5+ DLBCL. Design and Method From 1984 to 2002, 120 patients with CD5+ DLBCL were selected from 13 collaborating institutes. We analyzed the relationship between their morphological features and long-term survival. The current series includes 101 patients described in our previous study. Results Four morphological variants were identified: common (monomorphic) (n=91), giant cell-rich (n=13), polymorphic (n=14), and immunoblastic (n=2). Intravascular or sinusoidal infiltration was seen in 38% of the cases. BCL2 protein expression in CD5+ DLBCL was more frequent than in CD5− DLBCL (p=0.0003). Immunohistochemical analysis in 44 consecutive cases of CD5+ DLBCL revealed that 82% of these cases (36/44) were non-germinal center B-cell type DLBCL. The 5-year overall survival rate of the patients with CD5+ DLBCL was 38% after a median observation time of 81 months. Patients with the common variant showed a better prognosis than those with the other three variants (p=0.011), and this was confirmed on multivariate analysis. Overall, 16 patients (13%) developed central nervous system recurrence. Conclusions Our study revealed the morphological spectrum of CD5+ DLBCL, found that the incidence of central nervous system recurrence in this form of lymphoma in high, confirmed that CD5+ DLBCL frequently expresses BCL2 protein and showed that it is mainly included in the non-germinal center B-cell type of DLBCL.


American Journal of Pathology | 2002

Primary Thymic Extranodal Marginal-Zone B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue Type Exhibits Distinctive Clinicopathological and Molecular Features

Hiroshi Inagaki; John K. C. Chan; Josephine W. M. Ng; Mitsukuni Okabe; Tadashi Yoshino; Masataka Okamoto; Hiroshi Ogawa; Hiroshi Matsushita; Tomoyuki Yokose; Yoshihiro Matsuno; Naoya Nakamura; Tetsuro Nagasaka; Ryuzo Ueda; Tadaaki Eimoto; Shigeo Nakamura

Extranodal marginal-zone B-cell lymphoma (MZBL) of mucosa-associated lymphoid tissue (MALT) arising in the thymus is rare, with the largest series in the literature including only three cases. In the present study, we investigated 15 cases of thymic MALT lymphoma to systematically characterize its clinical, histopathological, and molecular features. There was a marked female predilection (male:female = 1:4), with a mean age of 55 years at diagnosis. There was a strong association with autoimmune disease, especially Sjögrens syndrome. Histologically, the thymic lymphoma showed the characteristic morphological features of extranodal MZBL of MALT type. Cysts were common. Prominent lymphoepithelial lesions were formed by centrocyte-like cells infiltrating and expanding the Hassalls corpuscles and epithelium lining the cysts. Plasmacytic differentiation was apparent in all cases. Notably, 13 of 15 cases expressed immunoglobulin (Ig) A phenotype; IgA expression in thymic MALT lymphoma was in striking contrast with the IgM phenotype observed in most of the Sjögrens syndrome-associated MZBLs and MALT lymphomas at other sites. Epstein-Barr virus was absent, and API2-MALT1 gene fusion, a recently reported MALT lymphoma-specific gene abnormality, was not detected in any case. Although one patient died of disease 85 months after the diagnosis, other patients were alive with overall 3-year and 5-year survival rates being 89% and 83%, respectively. Among the 22 patients reported previously and in the present series, at least 17 patients (77%) were Asians. These data indicate that thymic MALT lymphoma may represent a distinct subgroup of MALT lymphoma characterized by apparent predilection for Asians, a strong association with autoimmune disease, frequent presence of cysts, consistent plasma cell differentiation, tumor cells expressing IgA phenotype, and consistent lack of API2-MALT1 gene fusion.


The American Journal of Surgical Pathology | 1999

Nodal cytotoxic lymphoma spectrum: a clinicopathologic study of 66 patients.

Yoshitoyo Kagami; Ritsuro Suzuki; Hirohumi Taji; Yasushi Yatabe; Takahiro Takeuchi; Satoko Maeda; Eisei Kondo; Masaru Kojima; Tadashi Motoori; Yoshikazu Mizoguchi; Masataka Okamoto; Kazunori Ohnishi; Hirohiko Yamabe; Masao Seto; Michinori Ogura; Takashi Koshikawa; Toshitada Takahashi; Soji Kurita; Yasuo Morishima; Taizan Suchi; Shigeo Nakamura

The expression of cytotoxic granule-associated proteins has been reported in some T-cell or natural killer (NK)-cell lymphomas of mostly extranodal origin, but rarely of nodal origin except for anaplastic large cell lymphoma (ALCL) and Hodgkins disease (HD). This study analyzed 66 nodal lymphomas expressing T-cell intracellular antigen-1 (TIA-1) and/or granzyme B to characterize the clinicopathologic spectrum of these neoplasms. Four main groups could be delineated. The first group consisted of p80/anaplastic lymphoma kinase (ALK)-positive ALCL (n = 35). The patients were 2 to 62 years of age (median age, 16 years), and the lymphomas pursued a relatively indolent clinical course. The tumors were phenotypically of either T- or null-cell type with constant expression of CD30, epithelial membrane antigen (EMA), and p80/ALK, but not CD15 or BCL2. None harbored Epstein-Barr virus (EBV). The second group consisted of peripheral T/NK-cell lymphoma, the nodal high-grade cytotoxic type (n = 13). The patients were 29 to 72 years in age (median age, 55 years), and the tumors pursued an aggressive clinical course. The tumors often showed pleomorphic, anaplastic, or centroblastoid morphology, and were featured by either EBV association or CD56 expression. The third group consisted of peripheral T-cell lymphoma, of the nodal low-grade cytotoxic type (n = 8). The patients, three men and five women, were 31 to 75 years old (median age, 61 years). Notably, six of them exhibited lymphoepithelioid (Lennerts) lymphoma. The fourth group consisted of cytotoxic Hodgkins-like ALCL/HD (n = 10), included seven cases of Hodgkins-like ALCL and three cases of HD, and was characterized by the presence of Reed-Sternberg cells and often the CD15+ phenotype. The patients were all men except for one woman, and they ranged in age from 24 to 84 years (median age, 62 years). The link among these four groups was reinforced by the presence of a highly characteristic large cell with horseshoelike or reniform nuclei-the frequent expression of CD30 and EMA-and the often lack of T-cell receptor-alphabeta. In this series, the expression of p80/ALK and CD56 was also associated with favorable and poor prognoses respectively (p<0.001, log-rank test).


Cancer Research | 2004

Genome-Wide Array-Based Comparative Genomic Hybridization of Diffuse Large B-Cell Lymphoma Comparison between CD5-Positive and CD5-Negative Cases

Hiroyuki Tagawa; Shinobu Tsuzuki; Ritsuro Suzuki; Sivasundaram Karnan; Akinobu Ota; Yoshihiro Kameoka; Miyuki Suguro; Keitaro Matsuo; Motoko Yamaguchi; Masataka Okamoto; Yasuo Morishima; Shigeo Nakamura; Masao Seto

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin’s lymphoma and exhibits aggressive and heterogeneous clinical behavior. To genetically characterize DLBCL, we established our own array-based comparative genomic hybridization and analyzed a total of 70 cases [26 CD-positive (CD5+) DLBCL and 44 CD5-negative (CD5−) DLBCL cases]. Regions of genomic aberrations observed in >20% of cases of both the CD5+ and CD5− groups were gains of 1q21-q31, 1q32, 3p25-q29, 5p13, 6p21-p25, 7p22-q31, 8q24, 11q23-q24, 12q13-q21, 16p13, 18, and X and losses of 1p36, 3p14, 6q14-q25, 6q27, 9p21, and 17p11-p13. Because CD5 expression marks a subgroup with poor prognosis, we subsequently analyzed genomic gains and losses of CD5+ DLBCL compared with those of CD5−. Although both groups showed similar genomic patterns of gains and losses, gains of 10p14-p15 and 19q13 and losses of 1q43-q44 and 8p23 were found to be characteristic of CD5+ DLBCL. By focusing on the gain of 13q21-q34 and loss of 1p34-p36, we were also able to identify prognostically distinct subgroups among CD5+ DLBCL cases. These results suggest that array-based comparative genomic hybridization analysis provides a platform of genomic aberrations of DLBCL both common and specific to clinically distinct subgroups.


European Journal of Haematology | 2002

Simultaneous elevation of the serum concentrations of vascular endothelial growth factor and interleukin‐6 as independent predictors of prognosis in aggressive non‐Hodgkin's lymphoma

Nozomi Niitsu; Masataka Okamoto; Hirokazu Nakamine; Tadashi Yoshino; Jun-ichi Tamaru; Shigeo Nakamura; Masaaki Higashihara; Masami Hirano

Abstract: Therapeutic approaches for non‐Hodgkins lymphoma (NHL) are currently based on the International Prognostic Index (IPI). Research on biological prognostic factors has been actively pursued in recent years, with serum vascular endothelial growth factor (VEGF) and interleukin‐6 (IL‐6) being identified as prognostic factors for NHL. Here, we determined that serum VEGF and IL‐6 levels are independent prognostic factors for aggressive lymphoma. Compared with normal controls, serum VEGF and IL‐6 levels were significantly higher in patients with aggressive lymphoma or adult T‐cell leukemia/lymphoma. Furthermore, overall and disease‐free survival rates for patients with high levels of VEGF or IL‐6 were significantly poorer than for patients with low levels. In addition, the prognosis for patients with high levels of both serum VEGF and IL‐6 was significantly poorer than that for patients with high levels of either VEGF or IL‐6 or with low levels of both VEGF and IL‐6. Multivariate analyses of a variety of prognostic factors, including the five IPI factors, revealed that serum VEGF and IL‐6 were both independent prognostic factors for overall survival of aggressive lymphoma. Therefore, a combination of VEGF and IL‐6 represents a useful prognostic factor for aggressive lymphoma.


American Journal of Hematology | 2016

Clinicopathologic analysis of TAFRO syndrome demonstrates a distinct subtype of HHV‐8‐negative multicentric Castleman disease

Noriko Iwaki; David C. Fajgenbaum; Christopher S. Nabel; Yuka Gion; Eisei Kondo; Mitsuhiro Kawano; Taro Masunari; Isao Yoshida; Hiroshi Moro; Koji Nikkuni; Kazue Takai; Kosei Matsue; Mitsutoshi Kurosawa; Masao Hagihara; Akio Saito; Masataka Okamoto; Kenji Yokota; Shinichiro Hiraiwa; Naoya Nakamura; Shinji Nakao; Tadashi Yoshino; Yasuharu Sato

Multicentric Castleman disease (MCD) describes a heterogeneous group of disorders involving systemic inflammation, characteristic lymph node histopathology, and multi‐organ dysfunction because of pathologic hypercytokinemia. Whereas Human Herpes Virus‐8 (HHV‐8) drives the hypercytokinemia in a cohort of immunocompromised patients, the etiology of HHV‐8‐negative MCD is idiopathic (iMCD). Recently, a limited series of iMCD cases in Japan sharing a constellation of clinical features, including thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (R), and organomegaly (O) has been described as TAFRO syndrome. Herein, we report clinicopathological findings on 25 patients (14 males and 11 females; 23 Japanese‐born and two US‐born), the largest TAFRO syndrome case series, including the first report of cases from the USA. The median age of onset was 50 years old (range: 23–72). The frequency of each feature was as follows: thrombocytopenia (21/25), anasarca (24/25), fever (21/25), organomegaly (25/25), and reticulin fibrosis (13/16). These patients frequently demonstrated abdominal pain, elevated serum alkaline phosphatase levels, and acute kidney failure. Surprisingly, none of the cases demonstrated marked hypergammoglobulinemia, which is frequently reported in iMCD. Lymph node biopsies revealed atrophic germinal centers with enlarged nuclei of endothelial cells and proliferation of endothelial venules in interfollicular zone. 23 of 25 cases were treated initially with corticosteroids; 12 patients responded poorly and required further therapy. Three patients died during the observation period (median: 9 months) because of disease progression or infections. TAFRO syndrome is a unique subtype of iMCD that demonstrates characteristic clinicopathological findings. Further study to clarify prognosis, pathophysiology, and appropriate treatment is needed. Am. J. Hematol. 91:220–226, 2016.

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Nozomi Niitsu

Fujita Health University

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Masami Hirano

Fujita Health University

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Nobuhiko Emi

Fujita Health University

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Akinao Okamoto

Fujita Health University

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Yoko Inaguma

Fujita Health University

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Yasuo Morishima

Gulf Coast Regional Blood Center

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