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Dive into the research topics where Yoshiaki Iwasaki is active.

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Featured researches published by Yoshiaki Iwasaki.


Hepatology | 2006

Limitation of combination therapy of interferon and ribavirin for older patients with chronic hepatitis C

Yoshiaki Iwasaki; Hiroshi Ikeda; Yasuyuki Araki; Toshiya Osawa; Keiji Kita; Masaharu Ando; Toshinari Shimoe; Kouichi Takaguchi; Noriaki Hashimoto; Toshitsugu Kobatake; Minoru Tomita; Mitsuhiko Kawaguchi; Haruhiko Kobashi; Kohsaku Sakaguchi; Yasushi Shiratori

In contrast to the United States, Japanese patients with chronic hepatitis C currently treated with interferon are generally 10 to 15 years older. Older patients, however, tend to experience more frequent adverse events. This study was conducted to clarify the effect of patient age on the efficacy and safety of combination therapy. We consecutively enrolled 208 patients with naïve chronic hepatitis C. Patients were classified into three groups according to age: younger than 50 years of age (n = 52); 50 to 59 years old (n = 83); and 60 years of age or older (n = 73). Interferon alpha‐2b therapy was administered daily for 2 weeks, followed by 3 times per week for 22 weeks, while ribavirin was administered daily. Of the 208 study patients, discontinuation of therapy or dose reduction was required in 116 (56%) and was more frequent in older patient groups: 38%, 48%, and 77% for the <50, 50–59, and ≥60‐year‐old patient groups, respectively (P < .001). Multivariate analysis showed patient age to be independently associated with adherence to therapy. A sustained virological response was achieved in 77 (37%) patients, with genotype, viral load, and adherence to therapy associated with this achievement. A tendency toward a lower sustained virological response rate was seen in the older patients. In conclusion, patient age is an important factor contributing to the safety of combination therapy. Thus, treatment schedule should be modified, or other therapeutic modalities should be considered for older patients with chronic hepatitis C. (HEPATOLOGY 2006;43:54–63.)


Clinical Cancer Research | 2006

CpG island methylation status in gastric carcinoma with and without infection of Epstein-Barr virus

Moon-Sung Chang; Hiroshi Uozaki; Ja-Mun Chong; Tetsuo Ushiku; Kazuya Sakuma; Shunpei Ishikawa; Rumi Hino; Rita Rani Barua; Yoshiaki Iwasaki; Arai K; Hideki Fujii; Hideo Nagai; Masashi Fukayama

Purpose: EBV-associated gastric carcinoma shows global CpG island methylation of the promoter region of various cancer-related genes. To further clarify the significance of CpG island methylator phenotype (CIMP) status in gastric carcinoma, we investigated methylation profile and clinicopathologic features including overall survival in four subgroups defined by EBV infection and CIMP status: EBV-associated gastric carcinoma and EBV-negative/CIMP-high (H), EBV-intermediate (I), and EBV-negative (N) gastric carcinoma. Experimental Design: Methylation-specific PCR was applied to 106 gastric carcinoma cases. CIMP-N, CIMP-I, and CIMP-H status was determined by the number (0, 1-3, and 4-5, respectively) of methylated marker genes (LOX, HRASLS, FLNc, HAND1, and TM), that were newly identified as highly methylated in gastric cancer cell lines. The methylation status of 10 other cancer-related genes (p14, p15, p16, p73, TIMP-3, E-cadherin, DAPK, GSTP1, hMLH1, and MGMT) was also evaluated. Results: Nearly all (14 of 15) of EBV-associated gastric carcinoma exhibited CIMP-H, constituting a homogenous group (14%). EBV-negative gastric carcinoma consisted of CIMP-H (24%), CIMP-I (38%), and CIMP-N (24%). EBV-associated gastric carcinoma showed significantly higher frequencies of methylation of cancer-related genes (mean number ± SD = 6.9 ± 1.5) even if compared with EBV-negative/CIMP-H gastric carcinoma (3.5 ± 1.8). Among EBV-negative gastric carcinoma subgroups, CIMP-H gastric carcinoma showed comparatively higher frequency of methylation than CIMP-I or CIMP-N, especially of p16 and hMLH1. CIMP-N gastric carcinoma predominantly consisted of advanced carcinoma with significantly higher frequency of lymph node metastasis. The prognosis of the patients of CIMP-N was significantly worse compared with other groups overall by univariate analysis (P = 0.0313). Conclusion: The methylation profile of five representative genes is useful to stratify gastric carcinomas into biologically different subgroups. EBV-associated gastric carcinoma showed global CpG island methylation, comprising a pathogenetically distinct subgroup in CIMP-H gastric carcinoma.


The American Journal of Surgical Pathology | 2010

SALL4 represents fetal gut differentiation of gastric cancer, and is diagnostically useful in distinguishing hepatoid gastric carcinoma from hepatocellular carcinoma.

Tetsuo Ushiku; Aya Shinozaki; Junji Shibahara; Yoshiaki Iwasaki; Yoko Tateishi; Nobuaki Funata; Masashi Fukayama

The novel stem cell marker SALL4 has been identified as a diagnostic marker of germ cell tumors, especially yolk sac tumors, in gonadal organs. To clarify the significance of SALL4 as an oncofetal protein, we investigated SALL4 expression by immunohistochemistry in non-neoplastic stomach and gastric carcinoma with particular emphasis on á-fetoprotein (AFP)-producing gastric carcinoma, as AFP-producing gastric carcinoma shares expression of AFP and glypican 3 (GPC3) with yolk sac tumors and hepatic neoplasms. A total of 338 gastric carcinomas, 60 hepatocellular carcinomas, and 48 cholangiocellular carcinomas were studied by immunohistochemistry on tissue microarrays. In addition, more detailed whole tissue section immunohistochemistry was performed on non-neoplastic gastric tissue from 5 adult and 8 fetal specimens, 6 hepatoblastomas, and 31 cases of AFP-producing gastric carcinomas. SALL4 expression was observed in the neofetal stomach in gestational week 9 and disappeared thereafter. It was also identified by tissue microarray study in a fraction of gastric carcinomas (51 of 338, 15%), associated with older age (P=0.0001), male sex (P=0.0033), intestinal-type histology (P=0.0001), and synchronous liver metastasis (P=0.0047). AFP and GPC3 were closely associated with SALL4 expression in gastric carcinoma (both, P<0.0001), and a full-section study indicated that SALL4 was positive in all 31 cases of AFP-producing gastric carcinoma with diffuse staining in 24 cases (78%). Diffuse SALL4 expression was observed in the histologic patterns of hepatoid (89%), glandular (57%), and clear cell (39%) AFP-producing gastric carcinoma. In addition, SALL4 expression was completely negative in hepatoblastoma (n=6) and hepatocellular carcinoma (n=60). SALL4 is an oncofetal protein similar to AFP and GPC3, but it represents fetal gut differentiation in gastric carcinoma. SALL4 is a sensitive marker for AFP-producing gastric carcinoma and is especially useful to distinguish hepatoid gastric carcinoma from hepatocellular carcinoma.


Journal of Viral Hepatitis | 2010

Meta-analysis: interferon-alpha prevents the recurrence after curative treatment of hepatitis C virus-related hepatocellular carcinoma

Yasuhiro Miyake; Akinobu Takaki; Yoshiaki Iwasaki; Kazuhide Yamamoto

Summary.  Various clinical studies have indicated that interferon (IFN)‐alpha treatment prevents the development of hepatocellular carcinoma (HCC) in people chronically infected with hepatitis C virus. However, it has been controversial whether IFN‐alpha treatment prevents HCC recurrence. The aim of this study was to identify the preventive effect of IFN‐alpha treatment after curative therapy of primary tumours within the Milan criteria (three or fewer nodules 3 cm or less in diameter or a single nodule of 5 cm or less) on HCC recurrence. We conducted a meta‐analysis of five trials including 355 patients (167 patients received IFN‐alpha treatment after curative therapy of primary tumours) and estimated relative risks (RRs) and 95% confidence intervals (CIs) for the effect of IFN‐alpha on HCC recurrence according to the DerSimonian and Laird method. IFN‐alpha treatment after curative therapy of primary tumours significantly prevented HCC recurrence (RR 0.33; 95%CI 0.19–0.58, P < 0.0001) without a significant heterogeneity (Q = 4.52, P = 0.34). An evaluation using the Begg method suggested no evidence of publication bias. Sub‐group analyses revealed that IFN‐alpha treatment reduced HCC recurrence in two studies achieving sustained virologic response (SVR) rates >30% (RR 0.20; 95%CI 0.05–0.81, P = 0.02) and in three studies achieving SVR rates ≤30% (RR 0.44; 95%CI 0.23–0.84, P = 0.01). In conclusion, IFN‐alpha treatment after curative treatment of primary tumour within Milan criteria may be effective for the prevention of HCC recurrence, and higher SVR rate may be associated with better preventive effect of IFN‐alpha treatment on HCC recurrence.


Alimentary Pharmacology & Therapeutics | 2011

Alcohol consumption appears to protect against non-alcoholic fatty liver disease

Akio Moriya; Yoshiaki Iwasaki; S. Ohguchi; E. Kayashima; T. Mitsumune; Hideaki Taniguchi; Fusao Ikeda; Yasushi Shiratori; Kazuhide Yamamoto

Aliment Pharmacol Ther 2011; 33: 378–388


Journal of Surgical Oncology | 2013

Phase II study of preoperative chemotherapy with S-1 and cisplatin followed by gastrectomy for clinically resectable type 4 and large type 3 gastric cancers (JCOG0210).

Yoshiaki Iwasaki; Mitsuru Sasako; Seiichiro Yamamoto; Kenichi Nakamura; Takeshi Sano; Hitoshi Katai; Toshimasa Tsujinaka; Atsushi Nashimoto; Norimasa Fukushima; Akira Tsuburaya

We conducted a phase II study to evaluate the safety and efficacy of preoperative chemotherapy with S‐1 + cisplatin followed by gastrectomy in patients with linitis plastica (type 4) or large ulcero‐invasive‐type (type 3) gastric cancer.


Liver International | 2004

Risk factors for hepatocellular carcinoma in Hepatitis C patients with sustained virologic response to interferon therapy

Yoshiaki Iwasaki; Kouichi Takaguchi; Hiroshi Ikeda; Yasuhiro Makino; Yasuyuki Araki; Masaharu Ando; Haruhiko Kobashi; Toshitsugu Kobatake; Ryoji Tanaka; Minoru Tomita; Tomonori Senoh; Mitsuhiko Kawaguchi; Toshinari Shimoe; Koji Manabe; Keiji Kita; Junnosuke Shimamura; Kohsaku Sakaguchi; Yasushi Shiratori

Abstract: Background: Although a variety of papers demonstrated inhibited hepatocarcinogenesis with interferon (IFN) therapy for chronic hepatitis C, a small number of hepatocellular carcinomas (HCCs) were still observed even in sustained virologic responders.


Alimentary Pharmacology & Therapeutics | 2006

Persistent elevation of serum alanine aminotransferase levels leads to poor survival and hepatocellular carcinoma development in type 1 autoimmune hepatitis

Yasuhiro Miyake; Yoshiaki Iwasaki; Ryou Terada; R. Okamaoto; H. Ikeda; Yasuhiro Makino; Haruhiko Kobashi; K. Takaguchi; Kousaku Sakaguchi; Yasushi Shiratori

Although the prognosis of type 1 autoimmune hepatitis is generally good with immunosuppressive treatment, the disease progresses in some patients despite the treatment. The prognosis may be determined by the clinical course.


Liver International | 2006

Surveillance of hepatocellular carcinoma in patients with hepatitis C virus infection may improve patient survival

Hironori Tanaka; Kazuhiro Nouso; Haruhiko Kobashi; Yoshiyuki Kobayashi; Shin Ichiro Nakamura; Yasuhiro Miyake; Hideki Ohnishi; Kenji Miyoshi; Shouta Iwado; Yoshiaki Iwasaki; Kohsaku Sakaguchi; Yasushi Shiratori

Abstract: Background: The benefit of surveillance of hepatocellular carcinoma (HCC) for patients with hepatitis C virus (HCV) infection, in terms of long‐term survival, has not yet been established.


BMC Cancer | 2005

Functional promoter upstream p53 regulatory sequence of IGFBP3 that is silenced by tumor specific methylation

Tadashi Hanafusa; Toshiyuki Shinji; Hidenori Shiraha; Kazuhiro Nouso; Yoshiaki Iwasaki; Eichiro Yumoto; Toshiro Ono; Norio Koide

BackgroundInsulin-like growth factor binding protein (IGFBP)-3 functions as a carrier of insulin-like growth factors (IGFs) in circulation and a mediator of the growth suppression signal in cells. There are two reported p53 regulatory regions in the IGFBP3 gene; one upstream of the promoter and one intronic. We previously reported a hot spot of promoter hypermethylation of IGFBP-3 in human hepatocellular carcinomas and derivative cell lines. As the hot spot locates at the putative upstream p53 consensus sequences, these p53 consensus sequences are really functional is a question to be answered.MethodsIn this study, we examined the p53 consensus sequences upstream of the IGFBP-3 promoter for the p53 induced expression of IGFBP-3. Deletion, mutagenesis, and methylation constructs of IGFBP-3 promoter were assessed in the human hepatoblastoma cell line HepG2 for promoter activity.ResultsDeletions and mutations of these sequences completely abolished the expression of IGFBP-3 in the presence of p53 overexpression. In vitro methylation of these p53 consensus sequences also suppressed IGFBP-3 expression. In contrast, the expression of IGFBP-3 was not affected in the absence of p53 overexpression. Further, we observed by electrophoresis mobility shift assay that p53 binding to the promoter region was diminished when methylated.ConclusionFrom these observations, we conclude that four out of eleven p53 consensus sequences upstream of the IGFBP-3 promoter are essential for the p53 induced expression of IGFBP-3, and hypermethylation of these sequences selectively suppresses p53 induced IGFBP-3 expression in HepG2 cells.

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Tatsuro Yamaguchi

Tokyo Medical and Dental University

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