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Dive into the research topics where Masaru Muraoka is active.

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Featured researches published by Masaru Muraoka.


Hepatology | 2013

α-fetoprotein levels after interferon therapy and risk of hepatocarcinogenesis in chronic hepatitis C.

Yasuhiro Asahina; Kaoru Tsuchiya; Takashi Nishimura; Masaru Muraoka; Yuichiro Suzuki; Nobuharu Tamaki; Yutaka Yasui; Takanori Hosokawa; Ken Ueda; H. Nakanishi; Jun Itakura; Yuka Takahashi; Masayuki Kurosaki; Nobuyuki Enomoto; Mina Nakagawa; Sei Kakinuma; Mamoru Watanabe; Namiki Izumi

The effects of interferon (IFN) treatment and the post‐IFN treatment α‐fetoprotein (AFP) levels on risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis C (CHC) are unknown. To determine the relationship between AFP and alanine transaminase (ALT) levels and HCC risk, a cohort consisting of 1,818 patients histologically proven to have CHC treated with IFN were studied. Cumulative incidence and HCC risk were analyzed over a mean follow‐up period of 6.1 years using the Kaplan‐Meier method and Cox proportional hazard analysis. HCC developed in 179 study subjects. According to multivariate analysis, older age, male gender, advanced fibrosis, severe steatosis, lower serum albumin levels, non sustained virological response (non‐SVR), and higher post‐IFN treatment ALT or AFP levels were identified as independent factors significantly associated with HCC development. Cutoff values for ALT and AFP for prediction of future HCC were determined as 40 IU/L and 6.0 ng/mL, respectively, and negative predictive values of these cutoffs were high at 0.960 in each value. The cumulative incidence of HCC was significantly lower in patients whose post‐IFN treatment ALT and AFP levels were suppressed to less than the cutoff values even in non‐SVR patients. This suppressive effect was also found in patients whose post‐IFN treatment ALT and AFP levels were reduced to less than the cutoff values despite abnormal pretreatment levels. Conclusion: Post‐IFN treatment ALT and AFP levels are significantly associated with hepatocarcinogenesis. Measurement of these values is useful for predicting future HCC risk after IFN treatment. Suppression of these values after IFN therapy reduces HCC risk even in patients without HCV eradication. (Hepatology 2013;58:1253–1262)


Hepatology | 2012

Association of gene expression involving innate immunity and genetic variation in interleukin 28B with antiviral response

Yasuhiro Asahina; Kaoru Tsuchiya; Masaru Muraoka; Keisuke Tanaka; Yuichiro Suzuki; Nobuharu Tamaki; Yoshihide Hoshioka; Yutaka Yasui; Tomoji Katoh; Takanori Hosokawa; Ken Ueda; H. Nakanishi; Jun Itakura; Yuka Takahashi; Masayuki Kurosaki; Nobuyuki Enomoto; Sayuri Nitta; Naoya Sakamoto; Namiki Izumi

Innate immunity plays an important role in host antiviral response to hepatitis C viral (HCV) infection. Recently, single nucleotide polymorphisms (SNPs) of IL28B and host response to peginterferon α (PEG‐IFNα) and ribavirin (RBV) were shown to be strongly associated. We aimed to determine the gene expression involving innate immunity in IL28B genotypes and elucidate its relation to response to antiviral treatment. We genotyped IL28B SNPs (rs8099917 and rs12979860) in 88 chronic hepatitis C patients treated with PEG‐IFNα‐2b/RBV and quantified expressions of viral sensors (RIG‐I, MDA5, and LGP2), adaptor molecule (IPS‐1), related ubiquitin E3‐ligase (RNF125), modulators (ISG15 and USP18), and IL28 (IFNλ). Both IL28B SNPs were 100% identical; 54 patients possessed rs8099917 TT/rs12979860 CC (IL28B major patients) and 34 possessed rs8099917 TG/rs12979860 CT (IL28B minor patients). Hepatic expressions of viral sensors and modulators in IL28B minor patients were significantly up‐regulated compared with that in IL28B major patients (≈3.3‐fold, P < 0.001). However, expression of IPS‐1 was significantly lower in IL28B minor patients (1.2‐fold, P = 0.028). Expressions of viral sensors and modulators were significantly higher in nonvirological responders (NVR) than that in others despite stratification by IL28B genotype (≈2.6‐fold, P < 0.001). Multivariate and ROC analyses indicated that higher RIG‐I and ISG15 expressions and RIG‐I/IPS‐1 expression ratio were independent factors for NVR. IPS‐1 down‐regulation in IL28B minor patients was confirmed by western blotting, and the extent of IPS‐1 protein cleavage was associated with the variable treatment response. Conclusion: Gene expression involving innate immunity is strongly associated with IL28B genotype and response to PEG‐IFNα/RBV. Both IL28B minor allele and higher RIG‐I and ISG15 expressions and RIG‐I/IPS‐1 ratio are independent factors for NVR. (Hepatology 2012)


Cancer | 2014

Changes in plasma vascular endothelial growth factor at 8 weeks after sorafenib administration as predictors of survival for advanced hepatocellular carcinoma

Kaoru Tsuchiya; Yasuhiro Asahina; Shuya Matsuda; Masaru Muraoka; Toru Nakata; Yuichiro Suzuki; Nobuharu Tamaki; Yutaka Yasui; Shoko Suzuki; Takanori Hosokawa; Takashi Nishimura; Ken Ueda; Teiji Kuzuya; H. Nakanishi; Jun Itakura; Yuka Takahashi; Masayuki Kurosaki; Nobuyuki Enomoto; Namiki Izumi

A new predictive biomarker for determining prognosis in patients with hepatocellular carcinoma (HCC) who receive sorafenib is required, because achieving a reduction in tumor size with sorafenib is rare, even in patients who have a favorable prognosis. Vascular endothelial growth factor (VEGF) receptor is a sorafenib target. In the current study, the authors examined changes in plasma VEGF concentrations during sorafenib treatment and determined the clinical significance of VEGF as a prognostic indicator in patients with HCC.


World Journal of Gastroenterology | 2013

Hyperglycemia is a significant prognostic factor of hepatocellular carcinoma after curative therapy

Takanori Hosokawa; Masayuki Kurosaki; Kaoru Tsuchiya; Shuya Matsuda; Masaru Muraoka; Yuichiro Suzuki; Nobuharu Tamaki; Yutaka Yasui; Toru Nakata; Takashi Nishimura; Shoko Suzuki; Ken Ueda; H. Nakanishi; Jun Itakura; Yuka Takahashi; Namiki Izumi

AIM To evaluate whether metabolic factors are related to distant recurrence of hepatocellular carcinoma (HCC) and survival after curative treatment. METHODS This retrospective study included 344 patients whose HCC was treated curatively by radiofrequency ablation (RFA) therapy. The mean age was 67.6 years and the mean observation period was 4.04 years. The etiological background of liver disease was hepatitis B virus infection in 30, hepatitis C virus infection in 278, excessive alcohol drinking in 9, and other in 27 patients. The Child-Pugh classification grade was A (n = 307) or B (n = 37). The number of HCC nodules was one in 260, two in 61, and three in 23 patients. For surveillance of HCC recurrence after curative therapy with RFA, patients were radiologically evaluated every 3 mo. Factors associated with distant recurrence of HCC or survival were studied. RESULTS Inadequate maintenance of blood glucose in diabetic patients was associated with higher incidence of distant recurrence. The 1-, 2-, and 3-year recurrence rates were significantly higher in diabetic patients with inadequate maintenance of blood glucose compared with the others: 50.6% vs 26.8%, 83.5% vs 54.4%, and 93.8% vs 73.0%, respectively (P = 0.0001). Inadequate maintenance of blood glucose was an independent predictor of distant recurrence [adjusted relative risk 1.97 (95%CI, 1.33-2.91), (P = 0.0007)] after adjustment for other risk factors, such as number of HCC nodules [2.03 (95%CI, 1.51-2.73), P < 0.0001] and initial level of serum alpha fetoprotein (AFP) [1.43 (95%CI, 1.04-1.97), P = 0.028]. Obesity was not an independent predictor of recurrence. The incidence of distant recurrence did not differ between diabetic patients with adequate maintenance of blood glucose and non-diabetic patients. Among 232 patients who had HCC recurrence, 138 had a second recurrence. The 1-, 2-, and 3-year rates of second recurrence were significantly higher in diabetic patients with inadequate maintenance of blood glucose than in the others: 9.0% vs 5.9%, 53.1% vs 24.3%, and 69.6% vs 42.3%, respectively (P = 0.0021). Inadequate maintenance of blood glucose in diabetic patients [1.99 (95%CI, 1.23-3.22), P = 0.0049] and presence of multiple HCC nodules [1.53 (95%CI, 1.06-2.22), P = 0.024] were again significantly associated with second HCC recurrence. Inadequate maintenance of blood glucose in diabetic patients was also a significant predictor of poor survival [2.77 (95%CI, 1.38-5.57), P = 0.0046] independent of excessive alcohol drinking [6.34 (95%CI, 1.35-29.7), P = 0.019], initial level of serum AFP [3.40 (95%CI, 1.88-6.18), P < 0.0001] and Child-Pugh classification grade B [2.24 (95%CI, 1.12-4.46), P = 0.022]. Comparing diabetic patients with inadequate maintenance of blood glucose vs the others, the 1-, 2-, and 3-year survival rates were significantly lower in diabetic patients with inadequate maintenance of blood glucose: 92% vs 99%, 85% vs 96%, and 70% vs 92%, respectively (P = 0.0003). CONCLUSION Inadequate maintenance of blood glucose in diabetic patients is a significant risk factor for recurrence of HCC and for poor survival after curative RFA therapy.


Journal of Virology | 2015

Deep Sequencing and Phylogenetic Analysis of Variants Resistant to Interferon-Based Protease Inhibitor Therapy in Chronic Hepatitis Induced by Genotype 1b Hepatitis C Virus

Mitsuaki Sato; Shinya Maekawa; Nobutoshi Komatsu; Akihisa Tatsumi; Mika Miura; Masaru Muraoka; Yuichiro Suzuki; Fumitake Amemiya; Shinichi Takano; Mitsuharu Fukasawa; Yasuhiro Nakayama; Tatsuya Yamaguchi; Tomoyoshi Uetake; Taisuke Inoue; Tadashi Sato; Minoru Sakamoto; Atsuya Yamashita; Kohji Moriishi; Nobuyuki Enomoto

ABSTRACT Because of recent advances in deep sequencing technology, detailed analysis of hepatitis C virus (HCV) quasispecies and their dynamic changes in response to direct antiviral agents (DAAs) became possible, although the role of quasispecies is not fully understood. In this study, to clarify the evolution of viral quasispecies and the origin of drug-resistant mutations induced by interferon (IFN)-based protease inhibitor therapy, the nonstructural-3 (NS3) region of genotype 1b HCV in 34 chronic hepatitis patients treated with telaprevir (TVR)/pegylated interferon (PEG-IFN)/ribavirin (RBV) was subjected to a deep sequencing study coupled with phylogenetic analysis. Twenty-six patients (76.5%) achieved a sustained viral response (SVR), while 8 patients did not (non-SVR; 23.5%). When the complexity of the quasispecies was expressed as the mutation frequency or Shannon entropy value, a significant decrease in the IFNL3 (rs8099917) TT group and a marginal decrease in the SVR group were found soon (12 h) after the introduction of treatment, whereas there was no decrease in the non-SVR group and no significant decrease in mutation frequency in the IFNL3 TG/GG group. In the analysis of viral quasispecies composition in non-SVR patients, major populations greatly changed, accompanied by the appearance of resistance, and the compositions were unlikely to return to the pretreatment composition even after the end of therapy. Clinically TVR-resistant variants were observed in 5 non-SVR patients (5/8, 62.5%), all of which were suspected to have acquired resistance by mutations through phylogenetic analysis. In conclusion, results of the study have important implications for treatment response and outcome in interferon-based protease inhibitor therapy. IMPORTANCE In the host, hepatitis C virus (HCV) consists of a variety of populations (quasispecies), and it is supposed that dynamic changes in quasispecies are closely related to pathogenesis, although this is poorly understood. In this study, recently developed deep sequencing technology was introduced, and changes in quasispecies associated with telaprevir (TVR)/pegylated interferon (PEG-IFN)/ribavirin (RBV) triple therapy and their clinical significance were investigated extensively by phylogenetic tree analysis. Through this study, the associations among treatment response, changes in viral quasispecies complexity in the early stage of treatment, changes in the quasispecies composition, and origin of TVR-resistant variant HCV were elucidated.


Hepatology Research | 2014

Prospective comparison of real‐time tissue elastography and serum fibrosis markers for the estimation of liver fibrosis in chronic hepatitis C patients

Nobuharu Tamaki; Masayuki Kurosaki; Shuya Matsuda; Toru Nakata; Masaru Muraoka; Yuichiro Suzuki; Yutaka Yasui; Shoko Suzuki; Takanori Hosokawa; Takashi Nishimura; Ken Ueda; Kaoru Tsuchiya; H. Nakanishi; Jun Itakura; Yuka Takahashi; Kotaro Matsunaga; Kazuhiro Taki; Yasuhiro Asahina; Namiki Izumi

Real‐time tissue elastography (RTE) is a non‐invasive method for the measurement of tissue elasticity using ultrasonography. Liver fibrosis (LF) index is a quantitative method for evaluation of liver fibrosis calculated by RTE image features. This study aimed to investigate the significance of LF index for predicting liver fibrosis in chronic hepatitis C patients.


Oncology | 2014

Reduced Organic Anion Transporter Expression Is a Risk Factor for Hepatocellular Carcinoma in Chronic Hepatitis C Patients: A Propensity Score Matching Study

Yutaka Yasui; Atsushi Kudo; Masayuki Kurosaki; Shuya Matsuda; Masaru Muraoka; Nobuharu Tamaki; Shoko Suzuki; Takanori Hosokawa; Ken Ueda; Kotaro Matsunaga; H. Nakanishi; Kaoru Tsuchiya; Jun Itakura; Yuka Takahashi; Shinji Tanaka; Yasuhiro Asahina; Nobuyuki Enomoto; Shigeki Arii; Namiki Izumi

Objectives: Recent reports indicated that reduced SLC22A7 (a gene-encoding organic anion transporter 2) expression in noncancerous liver tissue predicts hepatocellular carcinoma (HCC) recurrence after curative resection. Our study aimed to elucidate the association between SLC22A7 expression and HCC development in chronic hepatitis C patients. Methods: HCC recurrence after local ablation therapy and SLC22A7 expression in noncancerous liver tissue were analyzed in 20 patients. Subsequently, the association between de novo HCC development and SLC22A7 expression was examined at baseline in 38 hepatitis C patients without HCC who subsequently developed HCC as well as in 76 hepatitis C patients who did not develop HCC and were matched for age, gender and stage of fibrosis. Results: In the patients whose HCC had been cured, reduced SLC22A7 expression in noncancerous liver tissue was significantly associated with a high incidence of multifocal HCC recurrence. In patients without HCC at baseline, cumulative incidence of de novo HCC development was significantly higher with a reduced SLC22A7 expression than with a normal expression (p = 0.01). This difference remained significant among patients without known risk factors for HCC like age and advanced fibrosis. Conclusion: Reduced SLC22A7 expression in the liver indicates a significant risk for HCC development in chronic hepatitis C, independently of other risk factors.


Mediators of Inflammation | 2015

Semiannual Imaging Surveillance Is Associated with Better Survivalin Patients with Non-B, Non-C Hepatocellular Carcinoma

Kuniaki Shindo; Shinya Maekawa; Nobutoshi Komatsu; Akihisa Tatsumi; Mika Miura; Mitsuaki Sato; Yuichiro Suzuki; Shuya Matsuda; Masaru Muraoka; Fumitake Amemiya; Mitsuharu Fukasawa; Tatsuya Yamaguchi; Yasuhiro Nakayama; Tomoyoshi Uetake; Taisuke Inoue; Minoru Sakamoto; Tadashi Sato; Nobuyuki Enomoto

Since it remains elusive whether and how the imaging surveillance affects the survival in patients with non-B, non-C hepatocellular carcinoma (NBNC-HCC), we conducted this retrospective study which investigated the association between the semiannual surveillance prior to HCC diagnosis and the survival in patients with the initial diagnosis of HCC induced by hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infections (N = 141) and non-B, non-C etiology (N = 30). It was demonstrated that surveillance was less frequently performed in the NBNC-HCC patients compared to that in HCC patients with HBV and/or HCV infections (B/C-HCC patients), and the survival was unfavorable in NBNC-HCC patients. On the other hand, the survival of NBNC-HCC patients with semiannual surveillance was significantly favorable than those patients without semiannual surveillance, and the survival was similar between B/C-HCCs and NBNC-HCCs with semiannual surveillance. In conclusion, though NBNC-HCC patients compared to B/C-HCC patients had poorer prognosis overall, these NBNC-HCC patients with semiannual surveillance had a better survival almost equivalent to the survival of B/C-HCC patients with semiannual surveillance, demonstrating the clinical utility of the semiannual imaging surveillance program for NBNC-HCCs.


Hepatology Research | 2018

HBV patients with low HBsAg and high HBcrAg titers have a high risk of HBV-related HCC: HBsAg and HBcrAg in HCC risk assessment

Yuichiro Suzuki; Shinya Maekawa; Nobutoshi Komatsu; Mitsuaki Sato; Akihisa Tatsumi; Mika Miura; Shuya Matsuda; Masaru Muraoka; Natsuko Nakakuki; Hiroko Shindo; Fumitake Amemiya; Shinichi Takano; Mitsuharu Fukasawa; Yasuhiro Nakayama; Tatsuya Yamaguchi; Taisuke Inoue; Tadashi Sato; Minoru Sakamoto; Atsuya Yamashita; Kohji Moriishi; Nobuyuki Enomoto

Although the viral markers hepatitis B surface antigen (HBsAg) and hepatitis B core‐related antigen (HbcrAg) could reflect intrahepatic hepatitis B virus (HBV) replication activity and constitute important biomarkers for hepatocellular carcinoma (HCC), the value of using these two markers in combination for assessing HCC risk has not been clarified in detail.


Journal of Gastroenterology | 2014

Non-invasive prediction of hepatocellular carcinoma development using serum fibrosis marker in chronic hepatitis C patients

Nobuharu Tamaki; Masayuki Kurosaki; Shuya Matsuda; Masaru Muraoka; Yutaka Yasui; Shoko Suzuki; Takanori Hosokawa; Ken Ueda; Kaoru Tsuchiya; Hiroyuki Nakanishi; Jun Itakura; Yuka Takahashi; Yasuhiro Asahina; Namiki Izumi

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Jun Itakura

University of Yamanashi

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Masayuki Kurosaki

Tokyo Medical and Dental University

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Namiki Izumi

Tokyo Medical and Dental University

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Yasuhiro Asahina

Tokyo Medical and Dental University

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