Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatic malignancy accounts for a large number of cancer-related deaths worldwide. Radiologic evaluation of the liver is critically important in the selection of patients for surgical treatment and newer modalities including computed tomographic arterial portography and intraoperative sonography show promise in the detection of small lesions. Advances in our understanding of the segmental anatomy of the liver, studies of intraoperative hepatic ischemia, and improved care of patients following major hepatic resections have extended the limits of surgical treatment of liver lesions, especially in cirrhotic patients with limited functional reserve. Along with hepatitis B, new data suggest that hepatitis C is also important as an agent causing hepatocellular carcinoma. In addition, the tumor suppressor gene p53 is frequently mutated in aflatoxin-induced hepatoma. In endemic regions, mass screening for early hepatocellular carcinoma appears to increase the surgical cure rate. Resectional surgery remains the best treatment for primary liver cancer and, in selected cases, liver transplantation is worthwhile. Liver resection for some patients with metastases of colorectal origin is now considered standard therapy and studies of regional chemotherapy for liver cancer are beginning to show promise. It remains to be seen whether adjuvant chemotherapy after liver resection will increase cure rates.
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PMID:Primary and secondary hepatic malignancies. 758 84

Fifty-one randomly selected primary squamous cell carcinomas of the head and neck, derived from the larynx (n = 18) and pharynx (oropharynx, n = 18, and hypopharynx, n = 15) were analyzed with centromeric probes for chromosomes 1, 7, 9, 11, 17, and 18 to study numerical aberrations, chromosome imbalances, and aneuploidy by fluorescence in situ hybridization. The tumors were grouped into nonmetastasizing (N0) tumors (from patients clinically free of lymph node metastases for at least 18 months after surgery, n = 25) and metastasizing (N1-3) tumors (n = 26). We found a significant association between the tumor ploidy and the nodal status; in the N0 group, diploidy prevailed, and the most common aberration was loss to monosomy for chromosome 9 (44%), whereas in the N1-3 group, aneuploidy predominated (P = 0.002). Specifically, these genomic changes associated with progression to metastasis were: (a) tetrasomic or polysomic chromosomes were detected in 17 of 26 N1-3 tumors but in none of the 25 N0 tumors (P < 0.0001); (b) heterogeneous chromosomal copy numbers (i.e., extensive chromosomal imbalances) were also much more frequent in the N1-3 tumors (69.2% versus 24.0% in the N0 group; P = 0.018); and (c) loss of chromosome 9 (73%) and gains of chromosomes 7 (35%) and 17 (31%) persisted, but in addition, loss of chromosome 18 occurred in 31%. Overexpression of the p53 protein correlated with an increased incidence of chromosomal imbalances and aneuploidy (P < 0.001) and, hence, constituted an additional risk factor. The lower metastatic potential of larynx tumors as compared with tumors from the pharynx was reflected by a lower incidence of these genomic changes. These specific patterns of chromosomal aberrations can characterize and distinguish different stages of tumor progression of squamous cell carcinomas of the head and neck and should be valuable diagnostic and prognostic markers.
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PMID:Distinct nonrandom patterns of chromosomal aberrations in the progression of squamous cell carcinomas of the head and neck. 758 47

Genetic changes found in human osteogenic sarcoma cells, including loss of the p53 and Rb tumor suppressor elements and overexpression of the cyclin G1 (CYCG1) proto-oncogene, suggest the potential of gene transfer as a treatment for metastatic disease. In this study, we examined the effects of antisense cyclin G1, in comparison with antisense cyclin D1 (CYCD1) and enforced expression of the universal cyclin-dependent kinase inhibitor p21WAF1/CIP1 on the proliferation of human MG-63 osteosarcoma cells. Retroviral vectors bearing antisense CYCG1 as well as antisense CYCD1 and WAF1/CIP1 (in sense orientation) driven by the Moloney murine leukemia virus long terminal repeat promoter inhibited the growth and/or survival of transduced MG-63 cells in 2-7 day cultures. This represents the first demonstration that cyclin G1 is essential for the survival and/or growth of human osteosarcoma cells. Cytostatic and cytopathic effects were accompanied by a significant increase in the incidence of apoptosis, as determined by immunocytochemical analysis of DNA fragmentation. Furthermore, transduction of MG-63 cells with a retroviral vector bearing the suicide gene, herpes simplex thymidine kinase (HStk), induced cell death on treatment with ganciclovir, exhibiting pronounced bystander effects. Taken together, the data affirm the feasibility of modulating inducible cell cycle control enzymes as a potential gene therapy approach in the clinical management of osteogenic sarcoma.
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PMID:Retroviral vector-mediated gene transfer of antisense cyclin G1 (CYCG1) inhibits proliferation of human osteogenic sarcoma cells. 758 20

It is often difficult to predict the outcome of melanoma in patients with Clark level III-IV disease. We sought to identify markers of cell proliferation which may be useful in predicting prognosis. Patients with Clark's level III-IV malignant melanoma who had no local recurrences or metastases were matched with patients of comparable level and thickness who did experience recurrences of metastases. Cell proliferation markers p53, proliferating cell nuclear antigen (PCNA), and Ki-67 were assessed by immunohistochemistry. DNA ploidy was determined by flow cytometry. There was no difference in the expression of p53, PCNA, and Ki-67 between patients with metastases and patients without metastases. However, patients with metastases were more likely to have an aneuploid tumor cell population than were patients without metastases (p < 0.03). Expression of cell proliferation markers do not appear to help predict prognosis in advanced level melanoma; however, aneuploidy may be associated with a greater probability of metastasis.
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PMID:Cell proliferation markers in predicting metastases in malignant melanoma. 759 19

Cell cycle delay has long been known to occur in mammalian cells after exposure to DNA-damaging agents. It has been hypothesized that the function of this delay is to provide additional time for repair of DNA before the cell enters critical periods of the cell cycle, such as DNA synthesis in S phase or chromosome condensation in G2 phase. Recent evidence that p53 protein is involved in the delay in G1 in response to ionizing radiation has heightened interest in the importance of cell cycle delay, because mutations in p53 are commonly found in human cancer cells. Because mammalian cells defective in p53 protein show increased genomic instability, it is tempting to speculate that the instability is due to increased chromosome damage resulting from the lack of a G1 delay. Although this appears at first glance to be a highly plausible explanation, a review of the research performed on cell cycle regulation and DNA damage in mammalian cells provides little evidence to support this hypothesis. Studies involving cells treated with caffeine, cells from humans with the genetic disease ataxia telangiectasia, and cells that are deficient in p53 show no correlation between G1 delay and increased cell killing or chromosome damage in response to ionizing radiation. Instead, G1 delay appears to be only one aspect of a complex cellular response to DNA damage that also includes delays in S phase and G2 phase, apoptosis and chromosome repair. The exact mechanism of the genomic instability associated with p53, and its relationship to the failure to repair DNA before progression through the cell cycle, remains to be determined.
Cancer Metastasis Rev 1995 Mar
PMID:Cell cycle regulation in response to DNA damage in mammalian cells: a historical perspective. 760 17

Cells heterozygous for mutations in p53 demonstrate extreme genomic instability and develop mutations detectable at the chromosome level as well as the molecular level. This genomic instability causes initially nontumorigenic ras-expressing immortal LFS cells to progress to a tumorigenic state presumably due to additional mutational events. It is not surprising that LFS families with these p53 mutations develop the additional mutations necessary for cancer to occur at such high frequencies. This observation is consistent with increased cancer rates in these families being due to abrogation of a rate limiting step rather than a rate expected for one less step in a multistep carcinogenic process. Although p53 has been shown to be able to function as a transcription factor, mutations in p53 appear to affect genomic stability in LFS fibroblasts with double minutes and telomeric associations being prominent early events. One possibility is that p53 controls the expression of genes required for fidelity of replication or telomerase activity. Alternatively p53 may itself be a replication factor like the transcription factor CTF. In the future, we plan to investigate whether p53 plays a direct role in replication.
Cancer Metastasis Rev 1995 Mar
PMID:Genomic instability due to germline p53 mutations drives preneoplastic progression toward cancer in human cells. 760 20

Cellular proliferation depends on the rates of both cell division and cell death. Tumors frequently have decreased cell death as a primary mode of increased cell proliferation. Genetic changes resulting in loss of programmed cell death (apoptosis) are likely to be critical components of tumorigenesis. Many of the gene products which appear to control apoptotic tendencies are regulators of cell cycle progression; thus, cell cycle control and cell death appear to be tightly linked processes. P53 protein is an example of a gene product which affects both cell cycle progression and apoptosis. The ability of p53 overexpression to induce apoptosis may be a major reason why tumor cells frequently disable p53 during the transformation process. Unfortunately, the same genetic changes which cause loss of apoptosis during tumor development, may also result in tumor cell resistance to anti-neoplastic therapies which kill tumor cells by apoptosis. Elucidation of the genetic and biochemical controls of these cellular responses may provide insights into ways to induce cell death and thus hopefully suggest new targets for improving therapeutic index in the treatment of malignancies.
Cancer Metastasis Rev 1995 Mar
PMID:P53, cell cycle control and apoptosis: implications for cancer. 760 18

The stability of the mammalian genome depends on the proper function of G1 and G2 cell cycle control mechanisms. Two tumor suppressors, p53 and retinoblastoma (Rb), play key roles in progression from G1 into S-phase. We address the mechanisms by which these proteins mediate a G1 arrest in response to DNA damage and limiting metabolic conditions. Gamma-irradiation induced a prolonged, p53-dependent G1 arrest associated with a long-term increase in the levels of the cdk-inhibitor p21WAFl/Cipl (p21). Microinjection of linear plasmid DNA also caused a G1 arrest. The p53-dependent arrest induced by inhibitors of UMP biosynthesis was reversible and occurred in the absence of detectable DNA damage. Both arrest mechanisms contribute to limiting the formation and propagation of damaged genomes. Cells containing mutant p53 but wild-type Rb do not generate methotrexate (Mtx) resistant variants. However, pre-treatment with DNA damaging agents prior to drug selection resulted in resistant clones containing amplified dihydrofolate reductase (DHFR) genes, suggesting that DNA breakage is a rate limiting step for gene amplification. The Mtx-induced arrest did not occur in cells with non-functional Rb. Rb acts as a negative regulator of the E2F transcription factors, and Rb-deficient primary mouse embryo fibroblasts (MEFs) produced elevated levels of mRNA and protein for key E2F target genes. Failure to prevent entry into S-phase in Rb-/- MEFs exposed to DNA-damaging or nutrient limiting conditions caused apoptosis and correlated with p53 induction. Taken together, these findings indicate a link between p53 and Rb function and suggest that their coordination insures correct entry into S-phase, minimizing the emergence of genetic variants.
Cancer Metastasis Rev 1995 Mar
PMID:Genetic instability as a consequence of inappropriate entry into and progression through S-phase. 760 22

DNA ploidy pattern was determined by flow cytometry and p53 overexpression was investigated immunohistochemically in 145 primary gastric cancers. Aneuploid patterns were found in 78 (65%) and diploid patterns in 67 (46%). Metastasising to lymph nodes was observed more frequently in cases with aneuploid tumors, as compared to those with diploid tumors (p < 0.01). DNA ploidy patterns were related to overexpression of p53. The incidences of overexpression of p53 in aneuploid tumors and diploid ones were 65% and 33%, respectively (p < 0.05). Thus, we suggest that gastric carcinomas with the aneuploid pattern have mutation of tumor suppressor gene p53 and high potential to metastasize to lymph nodes.
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PMID:[DNA ploidy pattern and p53 overexpression in gastric cancer]. 761 72

We report on an in vivo delivery system that attenuates the growth, in nude mice, of a malignant human breast cancer cell line containing a p53 mutation. Nude mice, inoculated with breast carcinoma cells, were injected every 10-12 days with a liposome-p53 complex via the tail vein. A significant reduction of greater than 60% in primary tumor volume was observed as compared to the control groups. Furthermore, when individual growth patterns of the tumors were assessed, we found that primary tumor size regressed in the majority of p53-treated animals (8/15), whereas only one tumor in the control groups (1/22) regressed. The eight tumors that regressed with the liposome-p53 complex showed no evidence of relapse for 1 month after the cessation of treatment. We also determined that the administration of the liposome-p53 complex reduced the incidence of metastases. The MDA-MB-435 tumor cells, transduced with the lacZ gene, facilitated quantitation of beta-galactosidase activity and tumor burden in the lungs. The number of metastatic cells in the lung was significantly lower in the p53-treated group (0.53 +/- 0.43 x 10(6), p < 0.01) than in either the vector-treated (8.1 +/- 3.7 x 10(6)) or untreated control groups (15.8 +/- 5.9 x 10(6)). Thus, systemic administration of the liposome-p53 complex reduced not only the size of the primary tumors but, more importantly, prevented the relapse and metastases of these tumors.
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PMID:Systemic gene therapy with p53 reduces growth and metastases of a malignant human breast cancer in nude mice. 761 97


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