Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatocarcinogenesis in hepatitis B virus transgenic mice was studied by means of a correlative cytomorphological and cytochemical approach at different time points in animals from 1 to 34 mo old. HBsAg-positive ground-glass hepatocytes emerged throughout the liver parenchyma in nearly all transgenic mice during the first 4 mo after birth. The panlobular expression of HBsAg persisted until foci of altered hepatocytes appeared (6 to 9 mo of age). Three different types of foci of altered hepatocytes-namely, glycogen-storage foci, mixed cell foci and glycogen-poor foci-developed. Hepatocellular adenomas and carcinomas appeared after 11 mo. Orcein staining revealed frequent transitions between ground-glass hepatocytes extensively expressing HBsAg and glycogen-storage (predominantly clear-cell) foci containing HBsAg-positive cytoplasmic components. Similar transitions between ground-glass hepatocytes and glycogenotic (clear) cells were often found in diffuse parenchymal glycogenosis at 11 or 12 mo. Remnants of HBsAg-positive material were also detected in mixed cell foci, glycogen-poor diffusely basophilic cell foci, hepatic adenoma and hepatocellular carcinoma. These findings suggest that ground-glass hepatocytes are the direct precursor of foci of altered hepatocytes and their neoplastic descendants. The extensive expression of HBsAg is gradually down-regulated during neoplastic transformation, just as the morphological the biochemical phenotypes of foci of altered hepatocytes, hepatic adenoma and hepatocellular carcinoma in transgenic mice resemble those described in chemical hepatocarcinogenesis. The predominant sequence of cellular changes leading from glycogen-storage (predominantly clear cell) foci to mixed cell foci, hepatic adenoma and hepatocellular carcinoma is characterized by a gradual decrease in the activities of glycogen synthase, phosphorylase, glucose-6-phosphatase and adenylate cyclase, whereas glucose-6-phosphate dehydrogenase and pyruvate kinase activities increase. These alterations indicate a shift from the glycogenotic state toward an increase in the pentose phosphate pathway and glycolysis.
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PMID:Hepatic preneoplasia in hepatitis B virus transgenic mice. 792 48

The hepatitis B virus (HBV)-encoded transcriptional activator HBV-X protein (HBx) was known to be involved in hepatocarcinogenesis. Hepatocarcinogenesis generally included an active angiogenesis that was mainly considered to be due to a local hypoxia in liver tissues. However, the exact mechanisms of HBx-induced hepatocarcinogenesis were poorly understood. In this study, we examined the role of HBx in the increased angiogenesis and the possible regulating mechanisms of HBx by hypoxia. We demonstrated that HBx stimulated the transcription of vascular endothelial growth factor (VEGF), a potent angiogenic factor, in HBx-stable transfectants. HBx-induced angiogenesis was confirmed by in vivo tumor angiogenesis assay, resulting in that the HBx transfectants increased the formation of new blood vessels compared to the control transfectants. Then, we demonstrated that the expression of HBx was enhanced after incubating HBV-infected hepatoma cells under hypoxia. Moreover, the activity of HBV enhancer 1 (Enh1) was increased when hepatoma cells transfected with the reporter plasmid containing HBV Enh1 were exposed to hypoxic conditions. These results strongly suggest that HBx may play a critical role in the hypoxia-induced angiogenesis through transcriptional activation of VEGF during hepatocarcinogenesis.
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PMID:Human hepatitis B virus X protein is a possible mediator of hypoxia-induced angiogenesis in hepatocarcinogenesis. 1067 26

Four cases of brain metastasis from hepatocellular carcinoma (HCC) associated with hepatitis B virus (HBV) are reported in an area not endemic for HBV infection. Two cases are unusual, since cerebral metastases were the only secondary localization. In these cases, no other sites of metastasization were detected either before or immediately following neurosurgical treatment. In all cases the expression of pRB, p53 and p16 tumor suppressor protein was studied with immunohistochemistry, both, in the primary and metastatic lesions. The pRB expression was as follows: in two cases, lack and moderate expression were observed both, in the primary and in the metastases; in the other two, pRB was not detected. In all cases p53 expression was negative both, in the primary and the metastases. P16 expression was moderately expressed in three cases, both in the primary and the metastases. In one case it was absent. Hepatocarcinogenesis is a multistep process, in which several oncogenes and oncosuppressor genes are involved. In four unusual cases of spread to the brain, we evidenced that tumor suppressor protein expression of p16, p53, and particularly pRB (its aberrated expression is usually associated with metastasis) were altered. We also suggest that HBV and its X protein (HBX) might play an important role in such aggressive behavior of the neoplasia.
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PMID:Brain metastasis from hepatocellular carcinoma associated with hepatitis B virus. 1238 72

The major risk factors and etiological agents responsible for development of hepatocellular carcinoma in humans have been identified and characterized. Among these are chronic infection with hepatitis B virus or hepatitis C virus, exposure to aflatoxin B1, and cirrhosis of any etiology (including alcoholic cirrhosis and cirrhosis associated with genetic liver diseases). Both chronic hepatitis and cirrhosis represent major preneoplastic conditions of the liver as the majority of hepatocellular carcinomas arise in these pathological settings. Hepatocarcinogenesis represents a linear and progressive process in which successively more aberrant monoclonal populations of hepatocytes evolve. Regenerative hepatocytes in focal lesions in the inflamed liver (chronic hepatitis or cirrhosis) give rise to hyperplastic hepatocyte nodules, and these progress to dysplastic nodules, which are thought to be the direct precursor of hepatocellular carcinoma. In most cases, the neoplastic transformation of hepatocytes results from accumulation of genetic damage during the repetitive cellular proliferation that occurs in the injured liver in response to paracrine growth factor and cytokine stimulation. Hepatocellular carcinomas exhibit numerous genetic abnormalities (including chromosomal deletions, rearrangements, aneuploidy, gene amplifications, and mutations), as well as epigenetic alterations (including modulation of DNA methylation). These genetic and epigenetic alterations combine to activate positive mediators of cellular proliferation (including cellular proto-oncogenes and their mitogenic signaling pathways) and inactivate negative mediators of cellular proliferation (including tumor suppressor genes), resulting in cells with autonomous growth potential. However, hepatocellular carcinomas exhibit a high degree of genetic heterogeneity, suggesting that multiple molecular pathways may be involved in the genesis of subsets of hepatocellular neoplasms. Continued investigation of the mechanisms of hepatocarcinogenesis will refine our current understanding of the molecular and cellular basis for neoplastic transformation in liver, enabling the development of effective strategies for prevention and/or more effective treatment of hepatocellular carcinoma.
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PMID:Mechanisms of human hepatocarcinogenesis. 1452 88

Hepatocarcinogenesis is a multistep process, but systematic analysis using a genetic or molecular approach to accurately delineate the different stages of hepatocellular carcinoma (HCC) development is scarce. In this study, we used genome-wide allelotyping to systematically evaluate the allelic alterations in the multisteps of hepatitis B virus-associated hepatocarcinogenesis. The overall fractional allelic loss (FAL) indices of cirrhosis, dysplastic nodules (DN), and HCC were significantly different, with a clear stepwise increase (P < 0.001). Loss of heterozygosity (LOH) was uncommon in cirrhotic livers (n = 24; mean FAL index +/- SD, 0.09 +/- 0.09; median, 0.07). In contrast, LOH was common in our 74 HCC nodules, which were predominantly hepatitis B virus-associated (mean FAL index +/- SD, 0.40 +/- 0.23; median, 0.38). The 18 DNs had FAL index (mean +/- SD, 0.27 +/- 0.19; median, 0.20) in between that of cirrhosis and HCC. Importantly, high-grade DNs had FAL index significantly higher than that of low-grade DNs (P = 0.031) and close to that of HCC, indicating that high-grade DNs were genetically closer to HCC. However, there was no significant difference in FAL indices between primary HCCs and their corresponding intrahepatic metastases, but this absence of major allelic losses in this transformation to a metastatic phenotype does not exclude small-scale chromosomal losses or gene deletions. To conclude, hepatitis B virus-associated hepatocarcinogenesis is a multistep process accompanied by stepwise increase in allelic losses from cirrhosis and low- and high-grade DN to HCC. Such allelic losses contribute to promote tumor development and progression.
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PMID:Hepatitis B virus-associated multistep hepatocarcinogenesis: a stepwise increase in allelic alterations. 1863 55

Hepatocarcinogenesis is a process attributed to progressive genomic changes which alter the hepatocellular phenotype producing cellular intermediates evolving into clearly neoplastic cells (hepatocellular carcinoma, HCC). During the preneoplastic phase, the liver is often the site of chronic hepatitis and/or cirrhosis, and this process leads to the production of monoclonal populations of aberrant and dysplastic hepatocytes that develop genetic and chromosomal alterations. At the moment three main molecular pathways of liver carcinogenesis have been described and several attempts of genetic classification of HCC have been proposed. The definition of genomic and molecular changes which occur during the development of HCC should improve the classification and prognostis of liver tumors. The development of sorafenib and other new targeted developing therapies were rendered possible by the discovery and understanding of the molecular and genetic pathogenesis of hepatocellular carcinoma. Besides viruses, such as Hepatitis B virus (HBV) and Hepatitis C virus (HCV), may contribute to cancer development by several ways; however, additional factors, such as host immunity and chronic inflammation and host cellular mutations also play a role in the transformation process. The understanding of these pathways will in the future enable the clinician to focus the treatment patients with HCC and customize single or combination therapy.
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PMID:Pathways and gene expression profiles in hepatocellular carcinoma. 2241 3

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. Hepatocarcinogenesis is a multistep process mainly associated with persistent infection with hepatitis B (HBV) or C (HCV) viruses and always involving the accumulation of genetic alterations over decades of chronic liver disease. Mutations in TP53 and CTNNB1 genes are considered the cancer drivers for HCC development with variable frequencies depending on the etiology. Here we present a comprehensive review evaluating somatic mutations in TP53 and CTNNB1 genes in HBV- and HCV-related HCCs. Moreover, we report the mutational analysis of TP53 (exons 4-9) and CTNNB1 (exon 3) as well as PIK3CA (exon 9) genes in HCC from Southern Italy. The overall mutation frequency of TP53 and CTNNB1 was 33.3%, while hotspot variations in PIK3CA were completely absent. CTNNB1 mutations were significantly associated with young age (P=0.019) and moderately/poorly differentiated HCV-related HCC (P=0.015). The extended analysis of genetic alterations will help to identify molecular markers for liver cancer prevention, diagnosis and treatment of HBV and HCV-associated liver cancer.
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PMID:Mutations in TP53, CTNNB1 and PIK3CA genes in hepatocellular carcinoma associated with hepatitis B and hepatitis C virus infections. 2358 69

Hepatocarcinogenesis is a multistep process that starts from fatty liver and transitions to fibrosis and, finally, into cancer. Many etiological factors, including hepatitis B virus X antigen (HBx) and p53 mutations, have been implicated in hepatocarcinogenesis. However, potential synergistic effects between these two factors and the underlying mechanisms by which they promote hepatocarcinogenesis are still unclear. In this report, we show that the synergistic action of HBx and p53 mutation triggers progressive hepatocellular carcinoma (HCC) formation via src activation in zebrafish. Liver-specific expression of HBx in wild-type zebrafish caused steatosis, fibrosis and glycogen accumulation. However, the induction of tumorigenesis by HBx was only observed in p53 mutant fish and occurred in association with the up-regulation and activation of the src tyrosine kinase pathway. Furthermore, the overexpression of src in p53 mutant zebrafish also caused hyperplasia, HCC, and sarcomatoid HCC, which were accompanied by increased levels of the signaling proteins p-erk, p-akt, myc, jnk1 and vegf. Increased expression levels of lipogenic factors and the genes involved in lipid metabolism and glycogen storage were detected during the early stages of hepatocarcinogenesis in the HBx and src transgenic zebrafish. The up-regulation of genes involved in cell cycle regulation, tumor progression and other molecular hallmarks of human liver cancer were found at later stages in both HBx and src transgenic, p53 mutant zebrafish. Together, our study demonstrates that HBx and src overexpression induced hepatocarcinogenesis in p53 mutant zebrafish. This phenomenon mimics human HCC formation and provides potential in vivo platforms for drug screening for therapies for human liver cancer.
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PMID:Liver-specific expressions of HBx and src in the p53 mutant trigger hepatocarcinogenesis in zebrafish. 2413 Aug 15

Hepatocellular carcinoma (HCC) is the third most common cause of cancer death worldwide. Hepatocarcinogenesis is a complex, multistep process. It is now recognized that HCC is a both genetic and epigenetic disease; genetic and epigenetic components cooperate at all stages of hepatocarcinogenesis. Epigenetic changes involve aberrant DNA methylation, posttranslational histone modifications and aberrant expression of microRNAs all of which can affect the expression of oncogenes, tumor suppressor genes and other tumor-related genes and alter the pathways in cancer development. Several risk factors for HCC, including hepatitis B and C virus infections and exposure to the chemical carcinogen aflatoxin B1 have been found to influence epigenetic changes. Their interactions could play an important role in the initiation and progression of HCC. Discovery and detection of biomarkers for epigenetic changes is a promising area for early diagnosis and risk prediction of HCC.
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PMID:Detection of epigenetic aberrations in the development of hepatocellular carcinoma. 2542 88

Hepatocellular carcinoma (HCC) is one of the most common malignancies leading to high mortality rates in the general population; in cirrhotic patients, it is the primary cause of death. The diagnosis is usually delayed in spite of at-risk population screening recommendations, i.e., patients infected with hepatitis B or C virus. Hepatocarcinogenesis hinges on a great number of genetic and molecular abnormalities that lead to tumor angiogenesis and foster their dissemination potential. The diagnosis is mainly based on imaging studies such as computed tomography and magnetic resonance, in which lesions present a characteristic classical pattern of early arterial enhancement followed by contrast medium "washout" in late venous phase. On occasion, when imaging studies are not conclusive, biopsy of the lesion must be performed to establish the diagnosis. The Barcelona Clinic Liver Cancer staging method is the most frequently used worldwide and recommended by the international guidelines of HCC management. Currently available treatments include tumor resection, liver transplant, sorafenib and loco-regional therapies (alcoholization, radiofrequency ablation, chemoembolization). The prognosis of hepatocarcinoma is determined according to the lesion's stage and in cirrhotic patients, on residual liver function. Curative treatments, such as liver transplant, are sought in patients diagnosed in early stages; patients in more advanced stages, were not greatly benefitted by chemotherapy in terms of survival until the advent of target molecules such as sorafenib.
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PMID:Diagnosis and treatment of hepatocellular carcinoma: An update. 2584 64


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