Published papers

© 2017, Springer International Publishing AG. Epigenetic alterations, such as alterations of histone modification and DNA methylation, occur in a genome-wide manner under precancerous conditions resulting from hepatitis B virus (HBV) or hepatitis C virus (HCV) infection followed by chronic hepatitis and cirrhosis, or aberrant lipogenesis and abnormal metabolism of reactive oxygen species that characterize the pathophysiology of non-alcoholic steatohepatitis (NASH). Once DNA methylation alterations occur at the precancerous stage, they are stably preserved on DNA double strands through methylation maintenance by DNA methyltransferase 1 (DNMT1). DNA methylation alterations associated with abnormalities of DNA methyltransferase, such as overexpression of DNMT1 and splicing alterations of DNMT3B, participate in multistage hepatocarcinogenesis from the precancerous stage to the malignant progression stage and are correlated with aggressiveness of hepatocellular carcinomas (HCCs) and poorer outcome of affected patients. A number of tumor-related genes, such as ATK3, APC, BMP4, CCL20, CDH1, CDKN2A, CDKN2B, CSPG2, DAB2IP, DCC, DLC1, DPT, DPYSL3, EMILIN2, FZD7, GRASP, GSTP1, HIST1H4F, IGFALS, MGMT, MZB1, NAT2, NEFH, NFATC1, PAX4, PDSS2, PER3, PROZ, PYCARD, RASSF1A, SPDY1, RUNX3, SCGB1D1, SFN, SMPD3, SOCS1, TIMP3, TLX3, TM6SF1, TRIM33, TRIM58, WFDC6, WNK2 and ZFP41, are known to be silenced by DNA hypermethylation in human HCCs. It is believed that DNA methylation alterations could be excellent biomarkers for carcinogenetic risk estimation and prognostication. To facilitate clinical application of DNA methylation diagnosis, a scaled-down device that allows quick and accurate analysis, even in small hospitals and clinics, is now being developed. One therapeutic strategy against HCC proliferation could involve a combination of epigenetic modifiers, such as a DNA methylation inhibitor, a histone deacetylase inhibitor and an S-adenosylhomocysteine hydrolase inhibitor, to sensitize cancer cells to conventional chemotherapies, in addition to eradication of hepatitis viruses for personalized and/or pre-emptive medical care.

Histological tumor extension into the prostate, urethra and urethra was examined in 52 specimens obtained by cystourethrectomy for transitional cell carcinoma of the bladder with one or more risk factors for urethral involvement. In four (21.1%) of 19 patients with diffuse carcinoma in situ in the bladder extending to the internal urethral orifice and prostatic urethra, the anterior urethra was affected by transitional cell carcinoma, including one specimen with invasion into the corpus spongiosum. However, none of 33 patients without these findings had synchronous anterior urethral transitional cell carcinoma involvement. It is recommended that patients with diffuse carcinoma in situ extending into the prostatic urethra undergo careful preoperative assessment of the anterior urethra before cystectomy. In other cases, the anterior urethra can be preserved and used for orthotopic neobladder replacement.

A study was conducted to clarify the contribution of β-catenin accumulation and mutation of the β-catenin gene to hepatocarcinogenesis. β-Catenin accumulation was examined immunohistochemically in 38 paired samples of hepatocellular carcinoma (HCC) and corresponding non-cancerous liver tissue. Gene mutation was analyzed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and direct sequencing using intronic primers encompassing exon 3. Neither accumulation nor mutation was detected in non-cancerous liver tissues that showed no remarkable histological features, chronic hepatitis or liver cirrhosis. Accumulation of β-catenin was seen in the nucleus, cytoplasm or cell membrane in 15 of 38 (39%) HCC samples, and gene mutation was seen in 9 of 38 (24%) HCC samples. Although there was a significant correlation between accumulation and mutation (P < 0.01), six HCCs without mutation also showed accumulation. Samples of early HCC showed neither accumulation nor mutation, and accumulation and mutation were each correlated significantly with portal vein tumor involvement (P < 0.05). The present results indicate that (1) mutation of exon 3 of the β-catenin gene can lead to β-catenin accumulation, although other mechanisms of accumulation may also operate in HCC, and (2) β-catenin accumulation and mutation of the β-catenin gene are not early events in hepatocarcinogenesis, and may be associated with the malignant progression of HCC.

We report a case of synovial sarcoma (SS) showing unusual histology at distant sites. A 47-year-old man was aware of a tumor on the sole of his left foot. After preoperative chemotherapy with a diagnosis of SS, wide excision was performed. During postoperative chemotherapy, multiple tumorous lesions developed in the bone (including the whole spine) and both lungs. The patient died 1 year later. Histologically, the excised tumor of the foot showed a biphasic cellular pattern typical of SS, whereas at autopsy the bone and lung lesions were composed only of undifferentiated small round cells with cytoplasmic fibrillar processes. Homer-Wright rosettes were also observed. Immunohistochemically, 80% of the bone and lung tumor cells expressed MIC2 protein homogeneously. To clarify whether the bone and lung round cell tumors were metastatic lesions or second malignancies, especially primary primitive neuroectodermal tumor (PNET)/Ewing's sarcoma (ES), we performed reverse transcription-polymerase chain reaction (RT-PCR) analysis of tumor type-specific fusion gene transcripts. The SYT/SSX fusion transcript was identified in both the foot and lung lesions, whereas the EWS/FLI1 transcript was not detected in either lesion. Therefore, we concluded that the multiple bone and lung tumors were poorly differentiated metastatic tumors, which arose from the SS of the foot. We also conclude that the identification of chimeric fusion transcripts can be successfully applied to poorly differentiated sarcomas and will help in the differential diagnosis of tumors that cannot be distinguished by conventional morphological examinations. Also, it should be remembered that cytoplasmic staining for MIC2 protein may occur in sarcomas other than PNET/ES. © 1999 Foundation for Promotion of Cancer Research.

Our study was designed to clarify the significance of silencing the E- cadherin gene, which is located on 16q22.1, due to CpG methylation during hepatocarcinogenesis. The CpG methylation status of primary hepatocellular carcinomas (HCCs) and corresponding liver tissues showing chronic hepatitis or cirrhosis, which are widely considered to be precancerous conditions, were assessed by digesting DNA with methylation-sensitive and non-sensitive restriction enzymes. CpG methylation around the promoter region of the E- cadherin gene was detected in 46% of liver tissues showing chronic hepatitis or cirrhosis and 67% of HCCs examined. Immunohistochemical examination revealed reduced E-cadherin expression in 59% of HCCs examined. CpG methylation around the promoter region correlated significantly with reduced E-cadherin expression in HCCs (p < 0.05). CpG methylation around the promoter region, which increases during the progression from a precancerous condition to HCC, may participate in hepatocarcinogenesis through reduction of E- cadherin expression, resulting in loss of intercellular adhesiveness and destruction of tissue morphology.

E-Cadherin, a cell adhesion molecule, which plays a key role in maintaining the epithelial phenotype, is regarded as an invasion-suppressor gene in light of accumulating evidence from in vitro experiments and clinical observations. In an attempt to clarify the mechanism responsible for inactivation of this gene in carcinomas, we investigated the methylation state around the promoter region by digestion of DNA with the methylation- sensitive restriction enzyme Hpa II, as CpG methylation of the promoter has been postulated to be a mechanism of transcriptional inactivation of some genes. We found that E-cadherin expression-negative carcinoma cell lines were accompanied by the hypermethylation state, whereas E-cadherin-positive cell lines were not. Furthermore, treatment of E-cadherin-negative carcinoma cells with the demethylating agent 5-azacytidine resulted in reexpression of the gene and reversion of scattered spindle-shaped cells to cells with epithelial morphology. These results suggest that hypermethylation around the promoter may be a mechanism of E-cadherin inactivation in human carcinomas and that treatment of E-cadherin-inactivated cells with a demethylating agent may cause gene expression reversion leading to epithelial morphogenesis with acquisition of the homophilic cell-cell adhesive property.

Objectives: To demonstrate the helical computed tomographic (CT) features of small polypoid lesions of the gallbladder and to establish a clinical strategy based on CT findings for the treatment of such lesions. Design: Validation cohort study. Setting: Tertiary care public hospital. Patients: Thirty-one patients with polypoid lesions of the gallbladder (≤3 cm) underwent CT followed by resection. Main Outcome Measure: The detectability of the lesions on both unenhanced and enhanced CT and the configuration of the lesions on enhanced CT were prospectively evaluated in comparison with the histopathological findings. Results: Unenhanced CT detected 14 (45%) of the 31 lesions, whereas enhanced CT detected all of the lesions. The detection rates of the neoplastic lesions (adenoma, adenocarcinoma, and metastatic tumor) and cholesterol polyps were 81% (13/16) and 7% (1/15), respectively (P<.001). Among the 20 lesions demonstrated as pedunculated, 6 (30%) were neoplastic, whereas 10 (91%) of the 11 lesions demonstrated as sessile were neoplastic (P<.001). When a lesion was demonstrated on unenhanced CT or its shape was sessile on enhanced CT, the case was diagnosed as a neoplastic lesion. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the CT diagnosis of the neoplastic lesions were 88% (14/16), 87% (13/15), 88% (14/16), 87% (13/15), and 87% (27/31), respectively. Conclusion: Computed tomography can differentiate neoplastic and nonneoplastic small polypoid lesions of the gallbladder and reliably identify the presence of neoplastic lesions that should be resected.

A study was performed to evaluate the significance of aberrations of the newly identified DNA demethylase, MBD2, in human carcinogenesis. Levels of expression of DNA demethylase mRNA were examined by reverse transcription followed by real-time quantitative detection of the PCR products in 32 samples of colorectal cancer tissue, 24 stomach cancers, and the corresponding noncancerous mucosae. DNA demethylase mRNA levels normalized with glyceraldehyde-phosphate dehydrogenase (GAPDH) mRNA were reduced in 31 (97%) of the 32 colorectal cancers and in 22 (92%) of the 24 stomach cancers when compared with the levels in the corresponding noncancerous mucosae. The average levels of DNA demethylase mRNA expression normalized with GAPDH mRNA in each of the colorectal (0.81 ± 0.55) and stomach (2.88 ± 0.23) cancers were significantly lower than in the noncancerous mucosae (1.90 ± 0.16 and 5.11 ± 0.34, respectively, p < 0.0001). There was no significant association between the DNA demethylase mRNA level and malignant potential in both colorectal and stomach cancers. These data suggest that reduced expression of DNA demethylase may play a role at a certain step of multistage carcinogenesis. Reduction of DNA demethylase mRNA expression may be, if anything, one of the early events of carcinogenesis, but may not participate in the malignant progression of tumors.

Conclusion: To differentiate serous cystadenoma from other cystic lesions communicating with the pancreatic duct, careful radiological examination is necessary. Background: Communication between the cystic cavity and the pancreatic duct in an ordinary serous cystadenoma is uncommon, although it is not uncommon in other cystic lesions, such as pseudocyst, mucinous cystadenoma/adenocarcinoma, and intraductal papillary tumor. Methods: A serous cystadenoma of the pancreas communicating with main pancreatic duct in a 76-yr-old male is reported. Results: The communication was preoperatively demonstrated by endoscopic retrograde cholangiopancreatography and confirmed by histopathological examination of the resected specimen.

A 26-year-old woman with systemic lupus erythematosus (SLE) developed dyspnea and hypoxemia on exertion. She died from rapidly progressive respiratory failure. Autopsy revealed right ventricular hypertrophy and occlusion of the pulmonary veins compatible with pulmonary venoocclusive disease (PVOD). Although PVOD has been reported in patients with suspected collagen vascular disease, this appears to be the first reported case of PVOD occurring in a patient with SLE.

This study was designed to determine whether changes in p27(Kip1) expression are involved in human hepatocarcinogenesis. We examined the p27(Kip1) mRNA expression in hepatocellular carcinomas and surrounding non-cancerous liver tissue samples from 21 patients using a reverse-transcriptase polymerase chain reaction assay. The mean p27(Kip1) mRNA expression levels (ratio of p27(Kip1)/β-actin mRNA) were significantly lower in hepatocellular carcinomas than in non-cancerous liver tissues (0.49±0.24 versus 0.57±0.22, P<0.05). p27(Kip1) mRNA expression was reduced in 11 (52%) of the 21 hepatocellular carcinomas when compared with the surrounding non-cancerous liver tissues. These findings suggest that reduced p27(Kip1) expression may be at least partly responsible for human hepatocarcinogenesis. Copyright (C) 1998 Elsevier Science Ireland Ltd.

There has been no English report of a long survivor after hepatectomy for metastasis from peri-ampullary malignancies, who had previously undergone pancreatoduodenectomy (PD) for primary disease. Herein, we report 7 patients of liver metastases who underwent 8 hepatectomies after PD for peri-ampullary malignancies. One patient whose liver metastasis was neuroendocrine tumor, survived 2 years and 6 months without recurrence after hepatectomy. Another patient who had 2 hepatectomies for metastasis from duodenal leiomyosarcoma survived for 3 years and 20 days after the first hepatectomy. Procedure of hepatectomy comprised 4 limited resections (including 1 second hepatectomy) and 4 lobectomies at the first resection. Hepatic inflow clamp was used in 6 out of 8 hepatectomies and 4 out of 8 hepatectomies did not require allogeneic blood transfusion. Bacterial contamination of the drained discharge from the cut surface of the liver, mostly representative of enteric organisms, was identified in all but 2 patients who were not examined. Subphrenic abscesses developed in 2 patients after removal of the drains. Thus, prophylactic use of abdominal drain is indispensable after hepatectomy for the patients with bilioenteric anastomosis.

From 0.5 to 3 days after subcutaneous injection of monocrotaline (MCT) 60 mg/kg, prominent accumulation of platelets in the pulmonary capillaries accompanied with significant elevation of the plasma serotonin level was observed. To clarify the role of serotonin, the in vivo and in vitro effects of the selective 5-HT2 receptor antagonist, DV-7028, on MCT-induced pulmonary hypertension were studied. Oral administration of DV-7028 (10 mg/kg, twice daily) significantly suppressed the MCT-induced elevation of pulmonary arterial pressure, right ventricular hypertrophy and medial thickening of the muscular-type pulmonary arteries which occurred 23 days after MCT administration. The plasma level achieved by oral administration of 10 mg/kg DV-7028 was more than 10(-7) M. The hyperreactivity to serotonin in isolated pulmonary artery segments from MCT-treated rats was significantly reduced by DV-7028 (10(-7) M). The present study suggests that serotonin, released from platelets and accumulated in pulmonary capillaries, contributes to the initiation and/or progression of pulmonary hypertension in MCT-treated rats.

Reduced or heterogeneous expression of E–cadherin has been demonstrated immunohistochemically in poorly differentiated carcinoma, which frequently shows weak intercellular adhesiveness and marked invasiveness. In vitro, not only reduced expression but also structural abnormalities of E–cadherin have been observed in human carcinoma cell lines which grow in a loosely adhering manner. To clarify the participation of structural abnormalities of E–cadherin in cancer invasion in vivo, sequence abnormalities were examined in the cadherin domain (exons 5, 6, 7 and 8) including the region essential for E–cadherin specific binding, using the polymerase chain reaction–single–strand conformation polymorphism method and direct sequencing in invasive lobular carcinoma of the breast, in which cancer cells become detached from each other and invade the stroma in a particularly scattered pattern. In 2 (10%) of the 20 cases examined, an identical sequence abnormality was detected in E–cadherin exon 7, i.e. a point mutation of codon 315 (AAT to AGT) which resulted in a single ainino acid substitution (asparagine to serine). This mutation may abolish the E–cadherin–mediated cell–cell adhesion and be at least partly responsible for the weak intercellular adhesiveness and scattered histological pattern of the tumor. Copyright © 1994, Wiley Blackwell. All rights reserved

Background: Nonfunctioning islet cell tumors (NFICTs) usually reach a large size prior to detection, at which stage patients have some symptoms or signs. Recently, NFICTs have been discovered in asymptomatic patients with increasing frequency owing to advances in diagnostic imaging techniques. This study investigated clinical, imaging and pathological features in recent cases of NFICT. Methods: The medical records, radiographs and pathological specimens of 16 patients with NFICT who were evaluated between April 1991 and March 1996 were reviewed. Results: Tumor sizes ranged from 0.8 to 17 cm (average, 5.2 cm). Five patients (31%) had some symptoms or signs at the time of diagnosis; however, the other 11 (69%) had no symptoms. Of 10 patients with a tumor of size 5 cm or less, nine were asymptomatic and all tumors were histologically benign. In contrast, in six patients with a tumor larger than 5 cm, four had some symptoms and five tumors were malignant. The detection rates of pancreatic tumor mass on ultrasonography and computed tomography were 94% (15/16) each. All 14 patients in whom the tumor was completely resected survived without recurrence; however, the remaining two patients with liver metastases died following recurrence. Conclusions: US and CT are useful in detecting NFICTs even if the tumor is small and the patient is asymptomatic. The detection of NFICTs of small size and their complete removal are essential for a successful cure.