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Dive into the research topics where Pavel V. Korita is active.

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Featured researches published by Pavel V. Korita.


Journal of Gastrointestinal Surgery | 2011

Surgical Outcomes for Hepatocellular Carcinoma in Nonalcoholic Fatty Liver Disease

Toshifumi Wakai; Yoshio Shirai; Jun Sakata; Pavel V. Korita; Yoichi Ajioka; Katsuyoshi Hatakeyama

BackgroundThe present study investigated outcomes following surgical resection of hepatocellular carcinoma (HCC) in nonalcoholic fatty liver disease (NAFLD).MethodsPatients (n = 225) undergoing resection for HCC were divided into three groups: hepatitis C viral group (n = 147), hepatitis B viral group (n = 61), and NAFLD group (n = 17). Clinicopathological characteristics and surgical outcomes were analyzed retrospectively.ResultsPatients in the NAFLD group were older (P < 0.001), with a higher body mass index (P < 0.001) and larger tumors (P = 0.002) than patients who were positive for hepatitis viral markers. Eight patients in the NAFLD group were found to have nonalcoholic steatohepatitis (NASH) histologically. Postoperative morbidity and 30-day mortality rates were significantly higher in the NAFLD group (59% and 12%, respectively) than in the hepatitis C viral (31% and 0.7%, respectively) and hepatitis B viral (28% and 3.3%; P = 0.043 and P = 0.016, respectively) groups. All deaths in the NAFLD group were in patients with NASH-related cirrhosis who had undergone right hemihepatectomy. Survival after resection was comparable among the three groups (P = 0.391), but patients with NAFLD showed better disease-free survival on univariate (P = 0.048) and multivariate (P = 0.020) analyses.ConclusionsSurgical resection may provide a survival benefit for patients with NAFLD-related HCC. Patients with NASH-related cirrhosis undergoing major hepatic resection should be treated carefully.


Human Pathology | 2008

Overexpression of osteopontin independently correlates with vascular invasion and poor prognosis in patients with hepatocellular carcinoma.

Pavel V. Korita; Toshifumi Wakai; Yoshio Shirai; Yasunobu Matsuda; Jun Sakata; Xing Cui; Yoichi Ajioka; Katsuyoshi Hatakeyama

This study retrospectively evaluated the immunohistochemical expression of 3 cell adhesion molecules (CAMs), E-cadherin, beta-catenin, and osteopontin, according to tumor grade in 125 surgically resected specimens of hepatocellular carcinoma (HCC). The aims of this study were to identify factors associated with vascular invasion and to elucidate the prognostic value of CAMs. The median follow-up time was 110 months. The levels of E-cadherin, beta-catenin, and osteopontin immunoreactivity were significantly associated with Edmondson-Steiner grade but not with tumor size. There was increased loss of E-cadherin, nonnuclear overexpression of beta-catenin, and overexpression of osteopontin in tumors of higher histologic grade. Vascular invasion was found in 44 (35%) of 125 resected specimens. Logistic regression analysis identified 3 tumor-related factors that were independently associated with vascular invasion-tumor size more than 3 cm, Edmondson-Steiner grades III to IV, and overexpression of osteopontin. Among the tested CAMs, osteopontin (P = .0110) and E-cadherin (P = .0287) were significant prognostic factors by univariate analysis. The Cox proportional hazard regression analysis revealed that Edmondson-Steiner grades III to IV (relative risk [RR], 3.028; P < .001), the presence of vascular invasion (RR, 1.964; P = .011), overexpression of osteopontin (RR, 1.755; P = .034), serum alpha-fetoprotein level more than 20 ng/mL (RR, 1.834; P = .037), and Child-Pugh classification B to C (RR, 1.880; P = .040) were found to be independently significant factors associated with survival after hepatectomy. These results suggest that overexpression of osteopontin independently correlates with vascular invasion and thus predicts poor survival for patients with HCC, whereas aberrant expression of E-cadherin or beta-catenin does not.


International Journal of Oncology | 2011

Alteration of p53-binding protein 1 expression as a risk factor for local recurrence in patients undergoing resection for extrahepatic cholangiocarcinoma

Toshifumi Wakai; Yoshio Shirai; Jun Sakata; Pavel V. Korita; Yasunobu Matsuda; Masaaki Takamura; Riuko Ohashi; Masayuki Nagahashi; Yoichi Ajioka; Katsuyoshi Hatakeyama

P53-binding protein 1 (53BP1) is an early DNA damage response-protein that is rapidly recruited to sites of DNA double-strand breaks. The presence of 53BP1 nuclear foci can be considered as a cytologic marker for endogenous double-strand breaks reflecting genomic instability. This study aimed to clarify the early DNA damage response mediated by 53BP1 in tumor specimens of ductal resection margins and to elucidate its predictive value for clinically evident local recurrence at ductal stumps in 110 patients undergoing resection for extrahepatic cholangiocarcinoma. The ductal resection margin status was classified as negative (85 patients), positive with carcinoma in situ (14 patients), or positive with invasive carcinoma (11 patients). The nuclear staining pattern of 53BP1 was evaluated by immunofluorescence. TUNEL analysis was used to calculate apoptotic index. Ductal margin status was the only independent risk factor for local recurrence (P=0.001). The cumulative probability of local recurrence at 5 years was 10%, 40% and 100% in patients with negative ductal margins, positive with carcinoma in situ and positive with invasive carcinoma, respectively (P<0.001). Of the 14 tumor specimens of carcinoma in situ, 10 showed diffuse localization of 53BP1 in nuclei (53BP1 inactivation) and 4 showed discrete nuclear foci of 53BP1 (53BP1 activation). All 11 tumor specimens of invasive carcinoma showed 53BP1 inactivation. Apoptotic index was markedly decreased in tumor specimens with 53BP1 inactivation compared to those with 53BP1 activation (median index, 0% vs. 22%; P<0.001). Among 14 patients with residual carcinoma in situ, the cumulative probability of local recurrence was significantly higher in patients with 53BP1 inactivation than in patients with 53BP1 activation (60% vs. 0% at 5 years; P=0.020). In conclusion, after resection for extrahepatic cholangiocarcinoma, clinically evident local recurrence at ductal stumps is closely associated with 53BP1 inactivation and decreased apoptosis.


Journal of Gastroenterology and Hepatology | 2010

Histological evaluation of intracapsular venous invasion for discrimination between portal and hepatic venous invasion in hepatocellular carcinoma

Masanori Ohashi; Toshifumi Wakai; Pavel V. Korita; Yoichi Ajioka; Yoshio Shirai; Katsuyoshi Hatakeyama

Background and Aim:  Histological criteria for intracapsular venous invasion (IVI) that would allow its discrimination between portal and hepatic venous invasion in hepatocellular carcinoma (HCC) have not been established.


Human Pathology | 2013

Alteration of the DNA damage response in colorectal tumor progression

Hiroaki Takabayashi; Toshifumi Wakai; Yoichi Ajioka; Pavel V. Korita; Naoyuki Yamaguchi

Recent studies have demonstrated increased levels of DNA double-strand breaks (DSBs) and activation of the DNA damage response (DDR) in precancerous lesions during cancer development. Those observations have not been fully elucidated using paraffin-embedded tissues of colorectal tumors. The aims of this study were to analyze the presence of DSBs and DDR activation mediated by p53-binding protein 1 (53BP1), which is a conserved checkpoint and DNA repair protein, and to clarify their association with colorectal tumor progression. We used immunohistochemical staining to investigate the expression of γH2AX, a sensitive marker for DSBs, in 152 colorectal tumors (46 low-grade adenomas, 25 high-grade adenomas, 25 intramucosal carcinomas, and 56 invasive carcinomas). The colocalization of γH2AX and 53BP1, which is strongly associated with the DSB repair process, was analyzed using double-label immunofluorescence. Elevated γH2AX expression was identified in 16 (16.7%) of 96 intramucosal neoplasias and in 19 (33.9%) of 56 invasive carcinomas. Double-label immunofluorescence occasionally revealed cells, particularly in invasive carcinoma, with γH2AX foci that did not colocalize with 53BP1. The percentage of tumor cells with γH2AX foci that colocalized with 53BP1 was significantly lower in invasive carcinoma than in intramucosal neoplasia (median percentage, 54.8% and 88.5%, respectively; P = .001). In conclusion, the number of cells with DSBs increases in intramucosal neoplasia and invasive carcinoma. The decreasing number of cells with colocalization of γH2AX and 53BP1 during the progression from intramucosal neoplasia to invasive carcinoma suggests that DDR, at least mediated by 53BP1, is inefficient during the process of cancer invasion.


Hepato-gastroenterology | 2011

Ribonucleotide reductase M1 expression in intrahepatic cholangiocarcinoma.

Toshifumi Wakai; Yoshio Shirai; Jun Sakata; Masaaki Takamura; Yasunobu Matsuda; Pavel V. Korita; Katsuki Muneoka; Masataka Sasaki; Yoichi Ajioka; Katsuyoshi Hatakeyama

BACKGROUND/AIMS Ribonucleotide reductase M1 (RRM1) is a key molecule for gemcitabine resistance. This study evaluated the immunohistochemical expression of RRM1 in resected specimens of intrahepatic cholangiocarcinoma (ICC) and investigated the efficacy of gemcitabine-based neoadjuvant chemotherapy in relation to RRM1 expression in tumors. METHODOLOGY A retrospective analysis was conducted on 34 consecutive Japanese patients who underwent resection of ICC. Of the 34 patients, 2 were treated with neoadjuvant chemotherapy consisting of gemcitabine 800mg/m2 every 2 weeks to address extrahepatic tumor extension. Expression of RRM1 in tumor specimens was assessed using immunohistochemistry and was classified as either positive or negative. RESULTS RRM1-positive expression was detected in 19/34 (56%) tumor specimens. Two patients were treated with gemcitabine-based neoadjuvant chemotherapy; one had a tumor specimen showing RRM1-positive expression and showed a 14% tumor reduction rate (stable disease); another patient had a tumor showing RRM1-negative expression and showed a 68% tumor reduction rate (partial response). Surgical procedures planned before administration of neoadjuvant chemotherapy were performed in both patients. CONCLUSIONS Neoadjuvant chemotherapy with gemcitabine for locally advanced ICC was well tolerated and did not impair planned surgical resections. Tumor expression of RRM1 may determine the efficacy of gemcitabine-based chemotherapy for patients with ICC.


Journal of Pediatric Surgery | 2009

Loss of carcinoembryonic antigen-related cell adhesion molecule 1 expression predicts metachronous pulmonary metastasis and poor survival in patients with hepatoblastoma

Mami Tsukada; Toshifumi Wakai; Yasunobu Matsuda; Pavel V. Korita; Yoshio Shirai; Yoichi Ajioka; Katsuyoshi Hatakeyama; Masayuki Kubota

PURPOSE Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a member of the carcinoembryonic antigen family of immunoglobulin-like adhesion molecules. The aim of this study was to test the hypothesis that loss of CEACAM1 expression in hepatoblastoma cells may promote hematogeneous metastasis and function as an adverse prognostic factor. METHODS Immunohistochemical expression of CEACAM1 in surgically resected specimens from 19 patients with hepatoblastoma was examined retrospectively. The CEACAM1 expression in the epithelial area of the tumor was classified into 2 categories as follows: diffuse expression, characterized by positive staining throughout the tumor specimen, or loss of expression, in which there were distinct areas of negative staining within the tumor specimen. RESULTS Of the 19 patients, 12 were classified as having tumors with diffuse expression, and 7 had loss-of-expression tumors. Survival after treatment was significantly worse in patients with tumors with loss of CEACAM1 expression (cumulative 5-year survival rate, 29%) than in patients with diffuse CEACAM1 expression (cumulative 5-year survival rate, 92%; P = .0062). Loss of CEACAM1 expression was a significant risk factor for metachronous pulmonary metastases (P = .0105). CONCLUSIONS Loss of CEACAM1 expression may reflect a high metastatic potential and thus indicate a poor prognosis for patients with hepatoblastoma.


Hepato-gastroenterology | 2011

Liver-intestine cadherin in intraepithelial neoplasia of intrahepatic cholangiocarcinoma.

Makoto Inoue; Yoichi Ajioka; Toshifumi Wakai; Masaaki Takamura; Pavel V. Korita; Yoshio Shirai; Katsuyoshi Hatakeyama

BACKGROUND/AIMS Liver-intestine cadherin (LI-cadherin) is a member of the cadherin superfamily and aberrant expression of LI-cadherin is associated with intestinal metaplasia. The aim of this study was to identify factors associated with LI-cadherin expression in biliary intraepithelial lesions of intrahepatic cholangiocarcinoma (ICC). METHODOLOGY We evaluated the immunoreactivity of LI-cadherin, MUC2, CDX2, MUC5AC and HGM, according to the grade of biliary intraepithelial lesion in 16 resected specimens of ICC without hepatolithiasis. RESULTS A total of 168 biliary intraepithelial lesions were classified into four grades: reactive change (42 lesions), biliary intraepithelial neoplasia (BilIN)-1 (10 lesions), BilIN-2 (40 lesions) and BilIN-3 (76 lesions). Biliary intraepithelial lesions were classified into three mucin phenotypes: null (46 lesions), gastric (97 lesions) and gastrointestinal phenotype (25 lesions). LI-cadherin expression was found in 45 (27%) of 168 biliary intraepithelial lesions. BilIN-2/3 (p<0.001), gastrointestinal phenotype (p=0.006) and CDX2 expression (p=0.002) were significantly associated with LI-cadherin expression. Logistic regression analysis revealed that BilIN-2/3 (p=0.002) was the only independently significant factor associated with LI-cadherin expression. CONCLUSIONS The grade of BilIN independently correlates with LI-cadherin expression in biliary intraepithelial lesions of ICC without hepatolithiasis, whereas the mucin phenotype or CDX2 expression does not.


Annals of Surgical Oncology | 2008

Appraisal of 1 cm Hepatectomy Margins for Intrahepatic Micrometastases in Patients with Colorectal Carcinoma Liver Metastasis

Toshifumi Wakai; Yoshio Shirai; Jun Sakata; Vladimir Valera; Pavel V. Korita; Kouhei Akazawa; Yoichi Ajioka; Katsuyoshi Hatakeyama


Oncology Reports | 2010

Multidrug resistance-associated protein 2 determines the efficacy of cisplatin in patients with hepatocellular carcinoma.

Pavel V. Korita; Toshifumi Wakai; Yoshio Shirai; Yasunobu Matsuda; Jun Sakata; Masaaki Takamura; Masahiko Yano; Ayumi Sanpei; Yutaka Aoyagi; Katsuyoshi Hatakeyama; Yoichi Ajioka

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