Kazufumi Sakurama

Okayama University, Okayama, Okayama, Japan

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Publications (31)90.18 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Thoracoscopic esophagectomy in the prone position (TEPP) might enable solo-surgery in cases requiring resection of the esophagus and the surrounding lymph nodes due to the associated advantages of good exposure of the surgical field and ergonomic considerations for the surgeon. However, no one approach can be for all patients requiring extensive lymphadenectomy. We recently developed an assistant-based procedure to standardize exposure of the surgical field. Patients were divided into 1 of 2 groups:a pre-standardization group (n=37) and a post-standardization group (n=28). The thoracoscopic operative time was significantly shorter (p=0.0037) in the post-standardization group (n=28; 267±31min) than in the pre-standardization group (n=37;301±53min). Further, learning curve analysis using the moving average method showed stabilization of the thoracoscopic operative time after the standardization. No significant differences were found in the number of mediastinal lymph nodes dissected or intraoperative blood loss between the 2 groups. There were also no significant differences in the complication rate. Assistant-based surgery and standardization of the procedure resulted in a well-exposed and safe surgical field. TEPP decreased the operative time, even in patients requiring extensive lymphadenectomy.
    Acta medica Okayama 02/2014; 68(2):111-7. · 0.65 Impact Factor
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    ABSTRACT: Since reported in the JCOG9907 trial, neoadjuvant chemotherapy prior to surgery has become the standard treatment for advanced (Stage II/III) esophageal cancers. However, more powerful neoadjuvant chemotherapy is required for the treatment of locally advanced cases or cases involving multiple lymph node metastases. At our institute, DCF therapy (docetaxel, cisplatin, and 5-fluorouracil) is administered selectively for the treatment of patients with far-advanced esophageal cancer. We treated 53 thoracic esophageal cancer patients who underwent surgery following neoadjuvant chemotherapy between January 2010 and December 2012. FP therapy (cisplatin and 5-fluorouracil) was administered to 43 patients, and DCF therapy to 7 patients who had far-advanced esophageal cancer. All patients treated with DCF therapy experienced grade 3 and 4 adverse events. With the exception of 1 patient, all patients who received DCF therapy could undergo curative surgery. DCF therapy could become an effective preoperative chemotherapy.
    Gan to kagaku ryoho. Cancer & chemotherapy 11/2013; 40(12):1612-4.
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    ABSTRACT: An 80-year-old woman, who had been administered α-glucosidase inhibitor for diabetes, was brought to the hospital with the sensation of abdominal fullness and pain. Abdominal computed tomography indicated pneumatosis cystoides intestinalis (PCI) in the small intestinal wall, with free air within the abdomen. A blood examination showed no increases in white blood cells or C-reactive protein level. The patient's condition improved with conservative therapy. PCI with pneumoperitoneum induced by α-glucosidase inhibitor is rare, with only 27 cases (excluding the present case) reported in Japan to date. In PCI with pneumoperitoneum, differentiation from gastrointestinal perforation is important and following the clinical symptoms over time is vital.
    Acta medica Okayama 04/2013; 67(2):123-8. · 0.65 Impact Factor
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    ABSTRACT: Esophageal squamous cell carcinoma (ESCC) remains one of the most aggressive cancers with poor prognosis regardless of a several reports that indicate a better therapeutic efficacy using some new chemotherapeutic agents. Recent drug development has contributed to an improved specificity to suppress mTOR activity by which many types of malignancies can be explosively progressed. Temsirolimus (CCI-779, TricelTM) is one of recently synthesized analogs of rapamycin and has provided better outcomes for patients with renal cell carcinoma. In this study, we experimentally evaluated an efficacy of targeting mTOR by temsirolimus for ESCC treatment, with an assessment of its survival advantage using an advanced ESCC animal model. First, we confirmed that the expression of phosphorylated mTOR was increased in 46 of 58 clinical ESCC tumor tissues (79.3%) and appeared to get strengthened with tumor progression. All of ESCC cell lines used in this study revealed an increase of mTOR phosphorylation, accompanied with the upregulation of hypoxia inducible factor-I α (HIF-1α), one of the critical effectors regulated by mTOR. Temsirolimus treatment apparently suppressed the activation of mTOR and its downstream effectors, resulting in the reduced ability of ESCC cell proliferation. Finally, the weekly administration of temsirolimus significantly diminished the size of subcutaneous tumors (vehicle, 3261.6 ± 722.0; temsirolimus, 599.2 ± 122.9; p = 0.007) in nude mice and effectively prolonged orthotopic esophageal cancer-bearing mice (median survival periods: control, 31 d; temsirolimus, 43 d; p = 0.0024). These data suggests that targeting mTOR by temsirolimus may become a therapeutic alternative for esophageal cancer, with a contribution to a better outcome.
    Cancer biology & therapy 01/2013; 14(3). · 3.29 Impact Factor
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    ABSTRACT: The functioning of an arteriovenous fistula (AVF) used for vascular access during hemodialysis has been assessed mainly by dilution methods. Although these techniques indicate the immediate recirculation rate, the results obtained may not correlate with Kt/V. In contrast, the clearance gap (CL-Gap) method provides the total recirculation rate per dialysis session and correlates well with Kt/V. We assessed the correlation between Kt/V and CL-Gap as well as the change in radial artery (RA) blood flow speed in the fistula before percutaneous transluminal angioplasty (PTA) in 45 patients undergoing continuous hemodialysis. The dialysis dose during the determination of CL-Gap was 1.2 to 1.4 Kt/V. Patients with a 10% elevation or more than a 10% relative increase in CL-Gap underwent PTA (n=45), and the values obtained for Kt/V and CL-Gap before PTA were compared with those obtained immediately afterward. The mean RA blood flow speed improved significantly (from 52.9 to 97.5cm/sec) after PTA, as did Kt/V (1.07 to 1.30) and CL-Gap (14.1% to -0.2%). A significant correlation between these differences was apparent (r=-0.436 and p=0.003). These findings suggest that calculating CL-Gap may be useful for determining when PTA is required and for assessing the effectiveness of PTA, toward obtaining better dialysis.
    Acta medica Okayama 12/2012; 66(6):443-7. · 0.65 Impact Factor
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    ABSTRACT: Heat shock protein 90 (HSP90), a molecular chaperone, has provoked great interest as a promising molecular target for cancer treatment, due to its involvement in regulating the conformation, stability and functions of key oncogenic proteins. At present, a variety of chemical compounds targeting HSP90 have been developed and have shown convincing anti-neoplastic activity in various preclinical tumor models. The aim of our study was to evaluate the antitumor effects of a novel HSP90 inhibitor, NVP-AUY922, in esophageal squamous cancer cells (ESCC). Four ESCC cell lines (TE-1, TE-4, TE-8, TE-10) were examined. NVP-AUY922 potently inhibited the proliferation of ESCC, particularly in PTEN-null TE-4 cells with a 2-3 times lower IC50 than the other three cell lines. Western blot analysis showed that PTEN-null TE-4 cells exhibited higher AKT and ERK activity, which contribute to cell proliferation and survival. NVP-AUY922 significantly suppressed the activity of AKT and ERK in TE-4 but not in PTEN-proficient TE-10 cells. Genetic modification experiments demonstrated that the sensitivity to NVP-AUY922 was decreased by exogenous transduction of PTEN in TE-4 and increased by silencing PTEN expression in intact PTEN-expressing TE-10, suggesting that the expression of PTEN may be associated with cell sensitivity in HSP90 inhibition. Furthermore, the enhanced activity of AKT in PTEN-silenced TE-10 was more easily suppressed by NVP-AUY922. Collectively, NVP-AUY922 exhibits a strong antiproliferative effect, revealing its potential as a novel therapeutic alternative to current ESCC treatment. The effect may be improved further by impeding PTEN expression.
    Oncology Reports 10/2012; · 2.30 Impact Factor
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    ABSTRACT: BACKGROUND: Conventional reconstruction after an esophagectomy uses a gastric tube, which commonly causes several postoperative complaints such as gastric acid reflux in long-term survival cases. Intestinal interposition between the remnant esophagus and the stomach is an option to reduce complaints, and in this study, the advantages of jejunal interposition reconstruction with a stomach preserving esophagectomy (SPE) were assessed. MATERIALS AND METHODS: Eleven cases of jejunal interposition with an SPE and 16 cases with gastric tube reconstruction as a control were subject to a comparison of operation time, amount of bleeding, postoperative quality of life, and endoscopic findings. RESULTS: The SPE group had a longer operation time (SPE: 560 ± 121 min, control 414 ± 83 min, P = 0.038), whereas there was no significant difference in blood loss. Postoperative weight loss was significantly recovered in the SPE group (SPE versus control = 94.0 ± 5.4% versus 87.5 ± 4.7% at 3 mo, P = 0.017; 97.2 ± 7.5% versus 85.0 ± 5.2% at 6 mo, P = 0.010), and there was a significant decrease in the occurrence of reflux symptoms such as heartburn, odynophagia, and cough when jejunal interposition with an SPE was done. Furthermore, reflux esophagitis and Barrett's epithelium were found in six out of 12 cases (50%) of the control group by postoperative endoscopy, while no cases in the SPE group had either condition (P < 0.01). CONCLUSIONS: This reconstruction method is a promising option to improve postoperative quality of life, mainly due to the long-term elimination of reflux esophagitis, which assists in the recovery of postoperative weight loss.
    Journal of Surgical Research 08/2012; · 2.02 Impact Factor
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    ABSTRACT: To assess the effects of a novel type 1 insulin-like growth factor receptor (IGF-1R) inhibitor, NVP-AEW541, on cell proliferation and signal transduction of esophageal cancer. Cell proliferation assay and western blot were conducted to assess the antitumor effects of NVP-AEW541. Genetic modification of RAS by expression vector was applied for overexpression of mutant RAS. More than 2 μmol/l of NVP-AEW541 was required to effectively inhibit the proliferation of esophageal cancer. NVP-AEW541 potently blocked the activation of IGF-1R and protein kinase B (PKB, also known as AKT), but not of mitogen-activated protein kinase kinase (MEK) and extracellular-signal-regulated kinases (ERK). Active RAS was not reduced by NVP-AEW541 in esophageal cancer cells TE-1, suggesting that insensitivity of esophageal cancer to NVP-AEW541 is due to the maintained RAS-MAPK activity, which did not arise from RAS mutation. Moreover, the transduction of mutant RAS reduced the sensitivity of TE-1 cells to NVP-AEW541. Stimulation of RAS-MAPK pathway is associated with resistance to NVP-AEW541 in esophageal cancer. Combining NVP-AEW541 with inhibitors/antibodies against RAS-MAPK signaling molecules might be more effective for use against esophageal cancer.
    Anticancer research 07/2012; 32(7):2827-34. · 1.71 Impact Factor
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    ABSTRACT: Peritoneal dissemination is one of the most terrible types of colorectal cancer progression. Focal adhesion kinase (FAK) plays a crucial role in the biological processes of cancer, such as cell attachment, migration, proliferation and survival, all of which are essential for the progression of peritoneal dissemination. Since we and other groups have reported that the inhibition of FAK activity exhibited a potent anticancer effect in several cancer models, we hypothesized that TAE226, a novel ATP-competitive tyrosine kinase inhibitor designed to target FAK, can prevent the occurrence and progression of peritoneal dissemination. In vitro, TAE226 greatly inhibited the proliferation and migration of HCT116 colon cancer cells, while their adhesion on the matrix surface was minimally inhibited when FAK activity and expression was suppressed by TAE226 and siRNA. In vivo, when HCT116 cells were intraperitoneally inoculated in mice, the cells could attach to the peritoneum and begin to grow within 24 h regardless of the pretreatment of cells with TAE226 or FAK-siRNA, suggesting that FAK is not essential, at least for the initial integrin-matrix contact. Interestingly, the treatment of mice before and after inoculation significantly suppressed cell attachment to the peritoneum. Furthermore, oral administration of TAE226 greatly reduced the size of disseminated tumors and prolonged survival in tumor-bearing mice. Taken together, a possible strategy for inhibiting peritoneal dissemination by targeting FAK with TAE226 appears to be applicable through anti-proliferative and anti-invasion/anti-migration mechanisms.
    Biochemical and Biophysical Research Communications 06/2012; 423(4):744-9. · 2.28 Impact Factor
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    ABSTRACT: Evaluating the status of disease progression is critical for planning a therapeutic strategy for esophageal cancer. In this regard, F-18 fluorodeoxyglucose-labeled positron emission tomography (PET) is one of the most useful diagnostic modalities. However, there is room to improve its diagnostic performance, such as distinguishing lymph nodal metastases from false positives. In this study, we examined the diagnostic accuracy of fluorodeoxyglucose PET accompanied by computed tomography imaging (PET/CT) to detect regional lymph nodal metastasis from esophageal squamous cell carcinoma (ESCC). A total of 102 patients diagnosed as ESCC were subjected to this study. These patients had a preoperative PET/CT examination to evaluate the existence of metastasis. The values of maximum standardized uptake value (SUVmax) in primary tumors and in metastasized lymph nodes were measured to analyze their relationship with various clinicopathologic characteristics including the status of tumor cell proliferation, which was assessed by immunohistochemistry for Ki-67. The SUVmax of the primary tumor was positively correlated with tumor size and vessel invasion, and was positively related with the SUVmax of lymph nodal metastasis, especially in cases of poorly differentiated ESCC. The SUVmax of metastasized lymph nodes was higher in larger-sized metastasized lymph nodes, whereas the Ki-labeling index of lymph nodal metastasis was positively related with the SUVmax per unit area (SUVmax/mm). The diagnostic accuracy of PET/CT (87.3%) was higher than that of conventional CT scans (78.4%). The improved diagnostic accuracy of PET/CT can be explained by its ability to detect actively progressive metastasis at an early phase regardless of size.
    Clinical nuclear medicine 10/2011; 36(10):854-9. · 3.92 Impact Factor
  • Nippon rinsho. Japanese journal of clinical medicine 08/2011; 69 Suppl 6:322-8.
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    ABSTRACT: The HSP90 molecular chaperone family is highly conserved and expressed in various organisms ranging from prokaryotes to eukaryotes. HSP90 proteins play essential housekeeping functions, such as controlling the activity, turnover and trafficking of various proteins, promoting cell survival through maintaining the structural and functional integrity of some client proteins which control cell survival, proliferation and apoptosis, and play an important role in the progression of malignant disease. HSP90 proteins are ATP-dependent chaperones and the binding and hydrolysis of ATP are coupled to conformation changes of HSP90, which facilitate client protein folding and maturation. Many natural and synthetic molecular compounds have been proposed as promising cancer therapy via disrupting the formation of complex ATP-HSP90-client proteins.
    Oncology Reports 06/2010; 23(6):1483-92. · 2.30 Impact Factor
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    ABSTRACT: Esophageal cancer is one of the most frequently occurring cancers in the world. Targeting therapy strategy of cancer with specific inhibitors is developing and has showed promising antitumor efficacy. It is known that mTOR is an important controller of cell growth. RAD001 (everolimus) is a specific inhibitor of mTOR that can block the mTOR signaling pathway. The purposes of this study was to explore the inhibitory effects of RAD001 on mTOR signaling and the mechanism of cell growth suppression by RAD001. We examined both the expression of mTOR, p70S6K and S6 in SEG-1 esophageal cancer cells and KOB-13 normal esophageal epithelial cells and the efficacy of RAD001 against SEG-1 esophageal cancer cells. mTOR, p70S6K and S6 were overexpressed in SEG-1 esophageal cancer cells compared with KOB-13 normal esophageal epithelial cells. SEG-1 esophageal cancer cells were sensitive to RAD001. The survival rate of the cells treated with RAD001 over 0.33 microM was significantly different compared with that of control (P<0.01). RAD001 inhibited the phosphorylation of mTOR (Ser2448) and S6 (Ser240/244) in different grades and the expressions of mTOR, p70S6K and S6. As a result, RAD001 induced a dose-dependent decrease in cell proliferation, G1/S arrest and damage of cell shape. Taken together, these data showed that RAD001 can inhibit mTOR signaling and proliferation in SEG-1 esophageal cancer cells in vitro. It offers a therapeutic intervention through inhibition of mTOR as a potential strategy for esophageal cancer.
    Oncology Reports 04/2010; 23(4):1167-72. · 2.30 Impact Factor
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    ABSTRACT: Autophagy is a cellular lysosomal degradation pathway involved in proteins and organelles recycling for promoting cell survival, development and homeostasis. It is a multistep process and genetic studies have identified many proteins that participate in autophagosome formation and fusion with lysosomes, and various signaling factors that associate with the regulation of autophagy. In general, autophagy acts as a cell protector and its dysfunction is correlated with diverse pathologies, such as neurodegeneration, liver, heart and muscle diseases, cancer, inflammation and ageing. However, its role in cell death increases the complexity of the autophagic degradation system. A broad understanding of autophagy, ranging from detailed processes, including induction, formation and degradation, to function in physiology and pathology, revealed by accumulating studies, may be helpful for formulating therapeutic strategies for autophagy-associated human diseases.
    International Journal of Molecular Medicine 04/2010; 25(4):493-503. · 1.96 Impact Factor
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    ABSTRACT: We established a promising new experimental animal model with an orthotopic xenograft of esophageal cancer that successfully represents poor oral intake, a major clinical feature of esophageal cancer. The advantage of this model is that no surgical technique is required, only the injection of a cell suspension by a needle and syringe via the esophageal lumen from the mouth, which provides a high reproducibility of tumor implantation and a rapid progress of outcome. We propose that this model is useful to study cancer-related outcomes and for developing new therapies for esophageal cancer, and we expect it to make a contribution to clinical practice.
    Cancer letters 02/2010; 293(2):207-12. · 5.02 Impact Factor
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    ABSTRACT: The type I insulin-like growth factor receptor (IGF-IR) and its associated signaling system play a significant role in tumorigenesis, tumor survival and progression, and cancer therapeutic resistance, and thus has provoked great interest as a promising target for cancer treatment. In this report we present the role of IGF-IR in gastrointestinal carcinomas whose pathology has been identified as tightly correlated with an abnormal expression and activation of IGF-IR. Reported data from experimental studies suggest the feasibility of targeted IGF-IR therapy in gastrointestinal carcinomas. Many types of inhibitors against IGF-IR have been developed. Inhibitors with anti-IGF-IR monoclonal antibodies and tyrosine kinase inhibitors currently undergoing preclinical and clinical evolution are also reviewed.
    Oncology letters 01/2010; 1(1):195-201. · 0.24 Impact Factor
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    ABSTRACT: Focal adhesion kinase (FAK) is a 125-kDa non-receptor protein tyrosine. Growth factors or the clustering of integrins facilitate the rapid phosphorylation of FAK at Tyr-397 and this in turn recruits Src-family protein tyrosine kinases, resulting in the phosphorylation of Tyr-576 and Tyr-577 in the FAK activation loop and full catalytic FAK activation. FAK plays a critical role in the biological processes of normal and cancer cells including the gastrointestinal tract. FAK also plays an important role in the restitution, cell survival and apoptosis and carcinogenesis of the gastrointestinal tract. FAK is over-expressed in cancer cells and its over-expression and elevated activities are associated with motility and invasion of cancer cells. FAK has been proposed as a potential target in cancer therapy. Small molecule inhibitors effectively inhibit the kinase activity of FAK and show a potent inhibitory effect for the proliferation and migration of tumor cells, indicating a high potential for application in cancer therapy.
    World Journal of Gastroenterology 12/2009; 15(47):5916-23. · 2.55 Impact Factor
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    ABSTRACT: In our institute, we introduced PET-CT examination as the preoperative and postoperative screening for esophageal cancer patients in April 2006. During two years before the introduction of PET-CT examination, we performed an intensive local control therapy (operation, RFA, definitive chemoradiotherapy) to 13 cases with single region recurrence (including 5 cases of cervical lymph nodes recurrence, 5 of local recurrence, 3 of distant metastatic recurrence). On the other hand, we performed an intensive local control therapy to 21 cases (including 4 cases of cervical lymph nodes recurrence, 10 of local recurrence, and 7 of distant metastatic recurrence) during two years after the introduction of PET-CT examination. In any pattern, there was a tendency of improvement in the prognosis of recurrent esophageal cancer patients. These results raised the possibility that PET-CT examination was useful for an early detection of the recurrent lesions in postoperative follow-up for esophageal cancer patients. And there might be a chance of curability in patients with single region recurrence by the early detection.
    Gan to kagaku ryoho. Cancer & chemotherapy 11/2009; 36(12):2465-7.
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    ABSTRACT: Focal adhesion kinase (FAK) is a 125-kDa non-receptor and non-membrane protein tyrosine. FAK can function with integrins and growth factor receptors to promote cell survival dependent kinase activity and nuclear FAK promotes cell proliferation and survival through FERM (FAK, ezrin, radixin, moesin) domain-enhanced p53 degradation independent kinase activity. Many previous studies have indicated that FAK plays a critical role in the biological processes of normal and cancer cells and FAK has been proposed as a potential target in cancer therapy. Small molecule inhibitors (PF-573,228; PF-562,271 and NVP-226) for use as potential cancer therapies have been developed. However, the detailed mechanism of the role for FAK in tumor cell generation and progression remain unclear, so future work is needed to explore these issues. New inhibitors that can be effectively inhibit the function of FAK still need to be explored due to the low specificity, and resistance.
    Oncology Reports 11/2009; 22(5):973-9. · 2.30 Impact Factor
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    ABSTRACT: Gastrointestinal stromal tumors often express gene mutations to c-KIT and platelet-derived growth factor receptor-alpha, both of which result in constitutive activations of their signaling pathways that are quite essential for the proliferation and survival of tumor cells in most clinical gastrointestinal stromal tumors. Targeting these molecules provides a dramatic improvement to therapeutic strategy. To identify a new therapeutic target for gastrointestinal stromal tumor treatment, we focused on focal adhesion kinase, which is reported to be an up-regulated gene in clinical gastrointestinal stromal tumors, because so far no one has examined its expression status at the protein level. In this study, Western blot analysis revealed that all 10 of the examined gastrointestinal stromal tumor tissues strongly expressed focal adhesion kinase protein and that phosphorylated focal adhesion kinase was detected in 9 of them. Next, we assessed the expression status of focal adhesion kinase and phosphorylated focal adhesion kinase in 51 cases of gastrointestinal stromal tumor by immunohistochemistry. Positive stainings for focal adhesion kinase and phosphorylated focal adhesion kinase were confirmed in 44 (86.3%) and in 40 cases (78.4%) of the 51 gastrointestinal stromal tumors, respectively. We further found that the focal adhesion kinase-positive staining rate became higher along with the increased status of malignant behavior. Moreover, when the 51 gastrointestinal stromal tumors were divided into 2 groups based upon their focal adhesion kinase expression status, the 5-year overall survival of patients in the focal adhesion kinase-positive group (66.5%) was significantly poorer than that in the focal adhesion kinase-negative group (100%). These results indicate that the up-regulation of focal adhesion kinase protein may also contribute to the tumor progression of gastrointestinal stromal tumors and that focal adhesion kinase is a potential target for gastrointestinal stromal tumor treatment.
    Human pathology 09/2009; 40(11):1643-9. · 3.03 Impact Factor

Publication Stats

157 Citations
90.18 Total Impact Points

Institutions

  • 2006–2013
    • Okayama University
      • • Department of Gastroenterological Surgery, Transplant, and Surgical Oncology
      • • Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
      Okayama, Okayama, Japan
  • 2009–2010
    • Inner Mongolia University
      Suiyüan, Inner Mongolia, China