Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatitis B virus (HBV) is clearly a factor in the development of hepatocellular carcinoma, but its mechanism of action remains obscure. One possibility is that the HBV integration event alters the expression of a nearby growth-regulatory cellular gene. A 9-kilobase (kb) DNA fragment containing an HBV insert plus flanking cellular sequences was cloned from a hepatoma specimen from Shanghai, People's Republic of China. Restriction mapping of the insert revealed a large inverted repeat structure consisting of both viral sequences (encompassing all of the core and pre-S regions and portions of the X and S genes) and at least 3 kb of unique cellular sequences. The virus-cell junction mapped 11 nucleotides from the DR1 region, in a position within the HBV X gene and included in the cohesive overlap region. A probe generated from 1.0 kb of the flanking cellular DNA mapped the viral insert to chromosome 17 in the region designated 17p11.2-17p12, which is near the human proto-oncogene p53. Sequence data from a portion of the flanking cellular DNA revealed a stretch of approximately 70 base pairs that showed highly significant homology with a conserved region of a number of functional mammalian DNAs, including the human autonomously replicating sequence 1 (ARS1).
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PMID:Structural analysis of a hepatitis B virus genome integrated into chromosome 17p of a human hepatocellular carcinoma. 284 34

To clarify the clinical significance of the mutation of p53 gene in hepatocellular carcinoma (HCC), 90 resected specimens from Japanese patients were assayed using a polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. p53 mutations were detected in 25 cases (27.8%) at exons 4, 5, 6, 7, and 8, and the most frequent region of the mutation was at exons 5 and 7. No statistically significant correlation was observed between the p53 mutations and the clinical features except for the preoperative alpha-fetoprotein (AFP) level (P < .05). According to the pathological features, prognostic factors, such as size of the tumor, vascular invasion, fibrous capsule infiltration, and intrahepatic metastasis, showed no relationship to the existence of the mutation. However, p53 mutations were significantly associated with the degree of differentiation of HCC; that is, the mutation was found in 19 cases of 53 poorly differentiated HCCs (35.9%) and 2 of 3 cases of anaplastic HCCs (66.7%). The presence of p53 mutations was associated with a shortened cancer-free survival (P < .001, by log rank test) and a shortened survival (P < .05). A multivariate analysis by the Cox regression analysis showed that the p53 mutations were an unfavorable prognostic factor related to recurrence (P < .005), which is especially significant within the first postoperative year. These results suggest that the mutations of p53 gene of HCC might be an independent prognostic predictor to help in the selection of candidates who should undergo more intensive postoperative treatment.
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PMID:The clinical significance of p53 gene mutation in hepatocellular carcinomas from Japan. 748 77

To investigate the expression of mutant p53 protein (mP53) and alpha-fetoprotein (AFP) during hepatocarcinogenesis, we detected immunohistochemically the specimens from 4 cases of normal human liver, 5 of cirrhosis, 5 of adenomatous hyperplasia (AH), and 16 of hepatocellular carcinoma (HCC) (by Edmondson classification. The 4 cases with normal liver showed negative mP53 and AFP. Four of the 5 cirrhosis cases were positive for mP53 and AFP. In 5 AH cases, 4 were positive for mP53 and AFP. In the 4 cases of grade I HCC, 2 were positive for mP53 and AFP. In the 6 cases of grade II HCC, 4 were positive for mP53 and AFP. In the 6 cases of grade III HCC, 1 showed mP53 positive staining but negative AFP, and 2 were negative for mP53 but positive for AFP, while 3 were negative for both mP53 and AFP. The results indicated that the mutation of p53 gene occurred in the early stage of hepatocarcinogenesis, and may be correlated with the initiation of hepatocarcinogenesis, and that mutant p53 protein probably related to the reactivation of AFP gene.
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PMID:[Mutation of p53 gene and expression of alphafetoprotein during hepatocarcinogenesis]. 752 28

Activation of cellular oncogenes and inactivation of anti-oncogenes have been postulated as important mechanisms during hepatocarcinogenesis. This study was conducted to detect abnormal levels of several proto-oncogenes (c-jun, c-fos, c-H-ras) and of the p53 and the alpha-fetoprotein gene in the liver during cirrhosis, a pathological process which predisposes to the development of hepatocarcinoma. Liver tissue from 11 patients with cirrhosis of different etiologies, and seven histologically normal liver fragments taken at the periphery of benign liver tumors of metastases were studied. Transcripts of the various oncogenes and of the alpha-fetoprotein gene were detected by in situ hybridization, and the p53 protein was revealed by immunocytochemistry. No overexpression of any of the mRNA tested or of the p53 protein was found in histologically normal liver in contact with benign or metastatic tumors. In contrast, 10 of the 11 specimens with cirrhosis (90.9%) displayed abnormally high levels of c-H-ras transcripts. Five samples with cirrhosis revealed a moderate increase in the level of c-fos mRNA. Only one case and two cases, respectively, exhibited increased levels of c-jun and alpha-fetoprotein mRNA. No cases were positive for the p53 antigen. Liver-cell proliferation, as assessed by immunocytochemistry with the Ki 67 monoclonal antibody, was low in both the group with cirrhosis and the control groups (0.49% and 0.55% positive cells, respectively). These data demonstrate that activation of c-H-ras mRNA is an almost constant finding in hepatocytes of livers with cirrhosis. This gene overexpression is not linked to hepatocellular proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of ras oncogene in livers with cirrhosis. 753 24

Hepatocellular carcinoma (HCC) is among the 10 most common tumors in the world. However, incidence is not evenly distributed across the world. In many instances, the proximate cause for the tumor can be identified. Chronic hepatitis B infection is probably the most common cause, followed by chronic hepatitis C. Other important causes are alcoholic liver disease, hemochromatosis, alpha 1-antitrypsin deficiency, and other chronic liver diseases. Although proximate causes may be identifiable, pathogenesis remains uncertain. Factors that may be important include the presence of Aflatoxin B1 in food, genetic changes induced by the hepatitis B virus, and repeated rounds of necrosis and regeneration, also induced by hepatitis viruses. The genes involved and the mutations necessary for hepatic carcinogenesis are unknown, with the sole exception of the p53 gene, which is probably a late phenomenon. Screening for HCC is widely practiced despite the lack of evidence of improved survival. The screening tests used include alphafetoprotein levels and ultrasonography. Screening can identify small tumors; however, survival may not be improved, because the presence of cirrhosis may limit the number of patients who can undergo resections; recurrences or second primary tumors are common; and the presence of chronic liver disease means that survival may be limited anyway. There are many different forms of therapy available; unfortunately, most have not been compared in randomized controlled trials. Surgery remains the therapy of choice if feasible. All other therapy is palliative, including chemotherapy, chemoembolization, hepatic artery embolization, various forms of radiotherapy, and various forms of ablative therapy.
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PMID:Hepatocellular carcinoma. 753 16

Thirty-six hepatocellular carcinoma (HCC) tissues obtained from 34 patients were classified according to histological diagnosis into six well-differentiated HCC, 20 moderately differentiated HCC and 10 poorly differentiated HCC. High molecular weight DNA was prepared from each tumour and the corresponding non-tumour tissue. Loss of heterozygosity (LOH) on chromosomes 4q, 5q, 10q, 11p, 16q, 17p, mutation of the p53 gene and polymorphism of intron 25 of the retinoblastoma (RB) gene were simultaneously analysed. The patients were composed of three cases of small HCC (the diameter of which was < 3 cm) and 31 cases of advanced HCC. Twenty-nine of 34 (85.3%) patients analysed had been exposed to hepatitis B virus and/or hepatitis C virus. The frequencies of LOH on seven chromosomes were 57.9% in 17p13.3, 45.1% in 17p, 45.1% in 11p, 41.9% in 5q, 41.9% in 16q24, 29.0% in 4q, 25.8% in 10q in advanced HCC (four of well differentiated, 18 of moderately differentiated and nine of poorly differentiated carcinoma). In contrast, LOH was observed on 4q, 5q, 16q and 17p in 33% (1/3) of the small HCC (two of well differentiated and one of moderately differentiated carcinoma). The mutation of the p53 genes and polymorphism of the RB gene were present in 25.8% (8/31) and 12.9% (4/31) of the advanced tumours, respectively, but the mutation was not found in small HCC. LOH on every chromosome and the p53 mutation were observed more frequently in more advanced tumours, and the genetic changes accumulated with the increase of the histopathological grade.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Loss of heterozygosity and analysis of mutation of p53 in hepatocellular carcinoma. 754 Apr 33

To search for genes related to hepatocarcinogenesis, the differential display technique for eukaryotic mRNA was conducted. We have cloned a gene that encodes the CD24 protein from the cDNA library of human hepatocellular carcinoma (HCC). A single 2.1-kb mRNA was identified in HCC specimens and the HuH-7 HCC cell line but only rarely in small amounts in nontumor livers. In 79 unicentric HCC, CD24 mRNA was overexpressed in 52 cases (66%), found in trace amounts in 11, and not detectable in 16 (20%). In 12 cases of multicentric HCC, CD24 mRNA was overexpressed in 21 (68%) of 31 tumor nodules and was helpful for the determination of tumor clonal origin. There was an increased frequency of CD24 mRNA overexpression in patients younger than 50 years with HCC (86% versus 59%, P < 0.025), in serum hepatitis B surface antigen-positive individuals (74% versus 48%, P < 0.023), in those with an elevated serum alpha-fetoprotein level (82%, versus 56%, P < 0.04), and in HCC with alpha-fetoprotein mRNA expression (82% versus 56%, P < 0.04). There was a strong correlation of CD24 mRNA overexpression with p53 gene mutation in HCC (91% versus 46%, P < 0.0005) and poorly differentiated HCC (82% versus 53%, P < 0.0008). Despite its correlation with p53 mutation and the unfavorable outcome of HCC with p53 mutation, the CD24 mRNA expression did not correlate with tumor size, tumor invasiveness, or patient's prognosis. Thus, the CD24 gene expression appears to be a common event in HCC and may serve as an early but not prognostic biomarker for malignant transformation of hepatocytes.
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PMID:Cloning and expression of CD24 gene in human hepatocellular carcinoma: a potential early tumor marker gene correlates with p53 mutation and tumor differentiation. 755 54

The p53 gene is frequently mutated in human tumors; in hepatocellular carcinomas, there is a high frequency of a specific mutation at codon 249 in regions with significant aflatoxin exposure. To assess the role of this p53 mutation in the development of hepatocellular carcinoma, a mutant murine p53 gene, p53ser246, which corresponds to human codon 249, was transfected into a differentiated, nontransformed hepatocyte cell line AML12. Expression of p53ser246 in this line resulted in a growth advantage when compared with either a control vector (which contains a large p53 deletion) or with a different p53 mutant, val135, not found in hepatocellular carcinoma. Overall, there was a threefold increase in colony formation after transfection with p53ser246 as compared with the control or p53val135 vectors, and the p53ser246 plates developed consistently larger colonies. Whereas clones expressing the control or p53val135 constructs showed no significant morphological changes, clones expressing p53ser246 showed increased heterogeneity (large multinucleated cells and areas of small crowded cells) without focus formation. In addition, the ser246 mutation imparted a growth advantage in serum-free media, suggesting less dependence on specific factors present in serum. None of the mutant p53 or control lines were capable of growth in soft agar or tumor formation in nude mice. Thus in this model, in which endogenous wild-type p53 expression is retained, a high level of mutant p53 expression is not sufficient to transform hepatocytes. Our findings indicate that p53ser246 has effects on hepatocytes that may result in a clonal growth advantage and suggest that additional factors are required for the development of hepatocellular carcinoma.
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PMID:Introduction of a murine p53 mutation corresponding to human codon 249 into a murine hepatocyte cell line results in growth advantage, but not in transformation. 755 82

The ability of p53 species (wild-type and mutant) to modulate the "differentiated" response of human hepatoma cell lines Hep3B and HepG2 to interleukin-6 (IL-6) was investigated. Transient transfection experiments were carried out in Hep3B and HepG2 cell cultures in which IL-6 was used to activate a beta-fibrinogen (beta Fib) enhancer/reporter construct containing two copies of the 36-base pair IL-6-response element (IL-6RE) (p beta FibCAT). Cotransfection with constitutive expression vectors for wild-type (wt) human or murine p53 inhibited the activation of the p beta FibCAT reporter by IL-6 in both Hep3B and HepG2 cells. Several mutant p53 species either did not inhibit the activation of p beta FibCAT or up-regulated the response. Hepatoma cell lines stably expressing the Val-135 temperature-sensitive mutant of murine p53 (wt-like at 32.5 degrees C and mutant-like at 37 degrees C) were derived from Hep3B cells and tested for the temperature-sensitive phenotype of their ability to synthesize and secrete fibrinogen and alpha 1-antichymotrypsin in response to IL-6. In an experimental protocol in which the parental Hep3B cells did not show a significant difference in plasma protein secretion at the two temperatures, hepatoma line 3 (p53Val-135+) had a greater response to IL-6 at 37 degrees C than parental Hep3B cells, while line 3 cells had a reduced response to IL-6 at 32.5 degrees C. Similarly, hepatoma lines 1 and 2 (both p53Val-135+) had reduced IL-6 responsiveness at 32.5 degrees C, whereas line 22 (transfected with pSVneo alone) and the parental Hep3B cells did not. These data indicate that mutations in p53 contained in tumor cells can modulate the "differentiated" response of these cells to cytokines.
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PMID:Modulation of interleukin-6-induced plasma protein secretion in hepatoma cells by p53 species. 755 62

p53 and c-myc are both known to be involved in apoptotic cell death as well as positive or negative regulation of cell proliferation, but it is not well established whether their functions are mechanistically correlated. We found that FAA-HTC1 cells, a rat hepatocellular carcinoma cell line, expressed c-myc independently of cell cycle and no detectable p53. To investigate possible co-operation between p53 and c-myc, the dexamethasone (Dex)-inducible wild type rat p53 was stably transfected into this cell line and c-myc expression was suppressed by treatment with c-myc antisense oligonucleotide (AS). p53 expression in the p53-introduced derivative resulted in apoptotic cell death, but it did not inhibit proliferative growth of the viable cells. On the other hand, when c-myc was suppressed in the p53-expressing cells, both apoptosis and cell growth were inhibited. These results indicate that p53 can act in the same cells either as a growth-inhibitor or apoptosis-inducer depending on the status of c-myc expression.
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PMID:Wild type p53 and c-myc co-operation in generating apoptosis of a rat hepatocellular carcinoma cell line (FAA-HTC1). 756 58


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