PubMed Health⌕ Search

Biomedical subjects

Eunsil Yu

Publications and source records attributed to Eunsil Yu.

33 records · Page 2Linked to original sources
PubMed2003

p16 Hypermethylation in the early stage of hepatitis B virus-associated hepatocarcinogenesis.

Abnormality of the p16 expression is involved in the pathogenesis of hepatocellular carcinoma (HCC), and hypermethylation of p16 gene is known as a major p16 inactivation mechanism. Cirrhotic nodule (CN) is now regarded as a preneoplastic lesion that is frequently associated with microscopic foci of HCC through dysplastic nodules (DNs). This observation clearly supports a multistep hepatocarcinogenesis from CNs through DNs. We thus examined the methylation status of p16 gene in HCCs surrounded by DNs and CNs to define the significance of p16 hypermethylation in the early stage of hepatocarcinogenesis. We tested 24 hepatitis B virus (HBV)-associated CNs, 37 DNs, and 18 HCCs within DNs that were microdissected from paraffin-embedded tissue sections. Frequency of p16 hypermethylation was significantly high in HCCs within DNs (15/18. 83.3%) and it increased from CNs (15/24. 62.5%) through DNs (26/37, 70.3%). Interestingly, 11 out of 12 (91.7%) HCC associated with methylation-positive DNs revealed hypermethylation of p16, and 18 out of 23 (78.2%) DNs associated with methylation-positive CNs showed p16 hypermethylation. These data suggest that p16 hypermethylation in the early stages, CNs and DNs may predispose to HCC. In addition, p16 methylation status of five cell lines with or without HBV infection was examined to test whether the high frequency of hypermethylation is related to HBV infection. HBV-infected cell lines were exclusively methylation-positive. These data suggest that high frequency of hypermethylation may be associated with hepatitis B virus infection.

DNA Methylation↗
PubMed2003

Expression of promyelocytic leukemia protein increases during the differentiation of human neuroblastoma cells.

The promyelocytic leukemia (PML) protein, whose fusion with retinoic acid receptor alpha is responsible for the tumorigenesis of acute promyelocytic leukemia, acts as a tumor suppressor in various types of human cancers. We analyzed the expression patterns of PML, in both primary neuroblastic tumors ( n=20) and two human neuroblastoma (NB) cell lines, SMS-KCNR (KCNR) and SH-SY5Y (SY5Y). The expression of PML, revealed as speckled or microgranular staining in the nuclei, was positively correlated with the differentiation status of NB cells in vivo, and was upregulated during the differentiation of KCNR and SY5Y cells following retinoic acid treatment. Screening of PML expression in human brain and sympathetic ganglia showed restricted expression of PML in mature neurons and glial cells, a result that was consistent with that in differentiated NB tumors. All these findings strongly suggest that increased PML expression is associated with growth inhibition and differentiation of human NB cells, and that it is of critical significance in the biology of NBs and in human nervous system development.

Adolescent↗
PubMed2003

Expression of DNA methyltransferases in multistep hepatocarcinogenesis.

Hypermethylation of cell cycle regulators and increased DNA methyltransferase 1 (Dnmt1) mRNA level have been reported in hepatocarcinogenesis. However, the expression of Dnmts has not yet been examined in hepatocellular carcinomas (HCCs). We examined 13 cases of HCCs in dysplastic nodules (DNs) and 28 cases of advanced HCCs for Dnmt1 and Dnmt3a, and compared the results with those of 9 cases of low-grade DNs, 24 cases of high-grade DNs, and 59 cases of nonneoplastic liver tissues from 59 cases of surgically resected livers by immunohistochemical staining. Nuclear expression of Dnmt1 was increased significantly in all HCCs in DNs and advanced HCCs compared with those of nonneoplastic livers, low-grade DNs, and high-grade DNs (P <0.05). Nuclear expression of Dnmt3a was not detectable in nonneoplastic liver and low-grade DN, whereas it was observed in high-grade DNs (7 of 24, 29.2%), HCCs in DNs (7 of 13, 53.8%), and advanced HCCs (11 of 28, 39.3%). Different from Dnmt1 immunostaining, cytoplasmic immunoreactivity for Dmnt3a was significantly decreased or absent in 13 of 24 cases of high-grade DNs (54.1%), 12 of 13 cases of HCCs in DNs (92.3%), and 22 of 28 cases of advanced HCCs (78.6%), compared with nonneoplastic livers and low-grade DNs (P <0.05). Our data suggest that Dnmt1 and Dnmt3a play a role in the early stage of hepatocarcinogenesis and that dysregulation of Dnmt3a may be involved in the progression of HCC. Furthermore, the significantly decreased cytoplasmic immunoreactivity for Dnmt3a in high-grade DNs and HCCs can be used as a diagnostic adjunct.

Carcinoma, Hepatocellular↗
PubMed2003

Intramucosal Helicobacter pylori in the human and murine stomach: its relationship to the inflammatory reaction in human Helicobacter pylori gastritis.

Intramucosal Helicobacter pylori (H. pylori) has been described in biopsy tissues and culture systems. However, the association of intramucosal H. pylori with histopathologic features has not been evaluated. The purpose of this study is to investigate the relationship between intramucosal H. pylori and inflammatory reactions in H. pylori infection. In 113 randomly selected human gastric biopsies and 20 murine stomachs, which were inoculated with SSI every day for a week, immunohistochemical analysis for intramucosal H. pylori was done and correlated with histologic parameters. Electron microscopic examination was done on murine stomachs. H. pylori infection was present in 104 gastric biopsies and 17 murine stomachs. Intraepithelial immunopositivity for H. pylori was detected in 27 of 104 (26%) biopsies and in 11 of 17 (65%) murine stomachs. Lamina proprial immunopositivity for H. pylori was present in 51 of 104 (48%) biopsies. Neutrophil-associated immunopositivity for H. pylori was observed in 22 of 90 (24%) biopsies with H. pylori chronic active gastritis. Lamina proprial and neutrophil-associated immunopositivity for H. pylori correlated significantly with the density of H. pylori and the grade of acute inflammatory reaction in H. pylori gastritis. Intramucosal location of H. pylori itself or its antigen is closely associated with acute inflammatory reactions and may play an important role in establishing a persistent infection in chronic H. pylori gastritis. Furthermore, lamina proprial and/or neutrophil-associated H. pylori appears to be more important than intraepithelial H. pylori in acute inflammatory reactions of H. pylori gastritis.

Animals↗
PubMed2003

Hypermethylation of the p16 gene and lack of p16 expression in hepatoblastoma.

Hepatoblastoma is the most frequent pediatric liver tumor that develops mostly in young children. Abnormal regulation of cell cycle regulatory genes including p16 has been described, displaying no p16 mRNA and p16 protein in hepatoblastomas. The inactivation of p16, leading to the disruption of cell cycle control is involved in many types of human malignancies. However, the mechanism of the p16 inactivation in hepatoblastomas has not yet been elucidated. In this present study, we examined the methylation status of the p16 gene promoter by using methylation-specific PCR in 24 cases of hepatoblastomas and in 20 cases of corresponding non-neoplastic liver tissue. Aberrant methylation of 5' CpG islands of p16 was present in 12 of 24 (50.0%) cases of hepatoblastoma. Clinicopathologic parameters were not associated with the methylation status of p16. To correlate the methylation status of p16 with the expression of p16, immunohistochemical staining was done in tumors and non-neoplastic liver tissue. All non-neoplastic liver tissues displayed moderate, but heterogeneous immunoreactivity for p16. Eight of 12 (66.6%) methylation-positive hepatoblastomas showed a complete lack of immunoreactivity for p16. The other 4 methylation-positive hepatoblastomas had heterogeneous immunoreactivity. Nine of 12 (75.0%) unmethylated cases of hepatoblastoma displayed diffuse immunoreactivity, whereas 3 cases of unmethylated hepatoblastoma were not immunostained for p16. Our data indicate that the hypermethylation of p16 is a major mechanism of the transcriptional repression of p16 in hepatoblastomas, and we suggest that the inactivation of p16, leading to the lack of p16, may play an important role in the tumorigenesis of hepatoblastomas.

Adult↗
PubMed2003

Primary extrapulmonary small cell carcinoma involving the stomach or duodenum or both: findings on CT and barium studies.

OBJECTIVE: The purpose of this study was to evaluate the CT and radiographic features of extrapulmonary small cell carcinoma involving the stomach or duodenum or both. CONCLUSION: Although the radiologic findings of extrapulmonary small cell carcinoma involving the stomach or duodenum or both appear to be variable and nonspecific, some distinguishing features are poor contrast enhancement, bulky exophytic mass, and minimal peritumoral infiltration.

Aged↗
PubMed2003

Sarcomatoid carcinoma of the gallbladder with a rhabdoid tumor component.

We report the case of a sarcomatoid carcinoma with a rhabdoid tumor component originating in the gallbladder, along with immunohistochemical and electron microscopic findings. A 61-year-old woman presented with a 5-month history of right upper quadrant pain. Ultrasonography and a computed tomographic scan indicated gallbladder cancer. She underwent a cholecystectomy and a common bile duct resection. A firm mass (4.5 cm in greatest dimension) was present in the neck portion of the gallbladder. The mass was firm, solid, yellowish gray, and granular with areas of necrosis. Microscopically, the tumor was a biphasic sarcomatoid carcinoma and consisted of diffusely arranged pleomorphic cells, focally showing rhabdoid features and neoplastic glands with focal mucin production. Heterologous components such as osteoid, chondroid, and rhabdomyoblastic elements were not identified. By immunohistochemical staining, we demonstrated that the rhabdoid cells coexpressed cytokeratin and vimentin. On electron microscopic examination, the rhabdoid tumor cells showed cytoplasmic whorls of intermediate filaments in the cytoplasm and eccentric nuclei. Two months postoperatively, the follow-up computed tomographic scan showed multiple intrahepatic metastases and omental seedings.

Carcinosarcoma↗
PubMed2002

Heterogeneous expression of Ku70 in human tissues is associated with morphological and functional alterations of the nucleus.

Ku70 is a subunit of DNA-protein kinase complex and involved in diverse intranuclear events including the repair of double-stranded DNA breaks. Ku70 is rich in the interphase nucleus of cultured cells. In human tissues, however, the distribution of Ku70 has not yet been systematically examined. To characterize the difference of Ku70 distribution between cells of human tissues and cultured cells, the expression of Ku70 was examined in various normal and neoplastic human tissues by immunohistochemistry and immunoblot. In addition, the role of Ku70 in the cellular response against ionizing radiation (IR) was analysed in fibroblasts after exposure to 5 Gy IR and apoptotic indices were examined in Ku70-overexpressed fibroblasts from an ataxia telangiectasia patient and in normal fibroblasts, before and after irradiation. In contrast to cultured cells, Ku70 was not detected in some interphase cells of human tissues and was distributed heterogeneously, even in the same nucleus. Ku70 expression was strikingly low in terminally differentiated cells such as neutrophils, eosinophils, glomerular capillary endothelial cells and fibroblasts, and was absent in spermatids. In spermatocytes, Ku70 was tightly integrated with chromosome filaments, unlike other somatic cells under mitosis. After exposure to IR, Ku70 expression was not increased in ataxia telangiectasia fibroblasts, but was significantly increased in normal fibroblasts. Most of the increased Ku70 was of soluble nuclear protein fraction. Furthermore, overexpression of Ku70 increased radiation resistance both in ataxia telangiectasia fibroblasts and normal fibroblasts. The presented data indicate that the distribution of Ku70 in cells of human tissues is closely associated with the cell cycle, cellular differentiation, nuclear shape and the process of repair of DNA damage caused by IR.

Adult↗
PubMed2002

Four cases of hepatitis B virus-related fibrosing cholestatic hepatitis treated with lamivudine.

Fibrosing cholestatic hepatitis (FCH) is a rare and extremely severe form of hepatitis B virus (HBV) infection. This condition was originally described in HBV-infected recipients after a liver transplantation. Recently, FCH has been reported not only in liver transplant recipients, but also in other immunosuppressed patients. It is characterized clinically by cholestatic hepatic dysfunction, and pathologically by severe periportal fibrosis, cholestasis, widespread balloon degeneration of hepatocytes, and only a mild infiltration of inflammatory cells. Without treatment, FCH is universally fatal within a few months of diagnosis. There have been only two isolated case reports of FCH with long-term patient survival, and one case report with treatment failure after lamivudine therapy. Because of the rarity of this clinical entity, the therapeutic efficacy of lamivudine in patients with FCH cannot be evaluated systematically. Here, we present four patients with HBV-related FCH treated with lamivudine. One received antineoplastic therapy for acute lymphoblastic leukemia, and the other three were renal graft recipients. Two patients who developed FCH after a renal transplantation survived with an improvement in liver function and were followed up for 20 and 30 months, respectively, and were found to be in good health. However, the other two patients died of sepsis, possibly as a consequence of the immunosuppression with hepatic failure despite lamivudine treatment. Our experience suggests that lamivudine can alter the grave natural history of FCH.

Adult↗
PubMed2002

Synchronous hepatocellular carcinoma and cholangiocarcinoma arising in two different dysplastic nodules.

We present the first reported case of explant cirrhotic liver that had synchronous cholangiocarcinoma and hepatocellular carcinoma arising in two different high-grade dysplastic nodules. The patient was a 55-year-old woman who had hepatitis B virus-associated liver cirrhosis for 3 years. The moderately differentiated cholangiocarcinoma occurred in high-grade dysplastic nodule with a 1.7-fold cell density compared with that of cirrhotic nodule. The hepatocellular carcinoma arose in a nodule-in-nodule pattern within a peripherally low-grade and centrally high-grade dysplastic nodule and had a 2.7-fold cell density compared with that of cirrhotic nodule. By immunohistochemistry, the tumor cells of the cholangiocarcinoma as well as bile ductular cells in dysplastic nodule were diffusely positive for cytokeratin 7, whereas hepatocellular carcinoma cells and dysplastic hepatocytes were negative for cytokeratin 7. The c-kit-positive hepatic progenitor cells were singly scattered between hepatocytes, and their number was highest in cirrhotic nodule and decreased in dysplastic nodule, whereas they were absent in cholangiocarcinoma and hepatocellular carcinoma arising in dysplastic nodules. Proliferation indices were progressively increased in cirrhotic nodule, dysplastic nodule, and cholangiocarcinoma or hepatocellular carcinoma, sequentially. These observations indicate that cholangiocarcinoma as well as hepatocellular carcinoma can develop in dysplastic nodule and that hepatic progenitor cells might play a role in the early stage of cholangiocarcinogenesis and hepatocarcinogenesis.

Bile Duct Neoplasms↗