Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to develop an effective therapeutic intervention for patients with pancreatic cancer, we examined the genetic alternations of pancreatic cancer. Based on these results, we are developing a new gene therapy targeting the genetic character of pancreatic cancer using mutant adenoviruses selectively replication-competent in tumor cells. Loss of heterozygosity (LOH) of 30% or more were observed on chromosome arms 17p (47%), 9p (45%), 18q (43%), 12q (34%), and 6q (30%). LOH of 12q, 17p, and 18q showed the significant association with poor prognosis. These data strongly suggest that mutation of the putative suppressor genes, TP53 and SMAD4 play significant roles in the disease progression. Based on this rationale, we are developing a new gene therapy targeting tumors without normal TP53 function. E1B-55kDa-deleted adenovirus (AxE1AdB) can selectively replicate in TP53-deficient human tumor cells but not cells with functional TP53. We evaluated the therapeutic effect of this AxE1AdB on pancreatic cancer without normal TP53 function. The growth of human pancreatic tumor in SCID mice model was markedly inhibited by the consecutive injection of AxE1AdB. Furthermore, AxE1AdB is not only the strong weapon but also useful carrier of genes possessing anti-tumor activities as a virus vector specific to tumors without normal TP53 function. It was reported that uracil phosphoribosyl transferase (UPRT) overcomes 5FU resistance. UPRT catalyzes the synthesis of 5-fluorouridine monophosphate (FUMP) from Uracil and phosphoribosylpyrophosphate (PRPP). The antitumor effect of 5FU is enhanced by augmenting 5-fluorodeoxyuridine monophosphate (FdUMP) converted from FUMP, which inhibits Thymidylate Synthetase (TS). The therapeutic advantage of restricted replication competent adenovirus that expresses UPRT (AxE1AdB-UPRT) was evaluatedin an intra-peritoneal disseminated tumor model. To study the anti-tumor effect of AxE1AdB-UPRT/5FU, mice with disseminated AsPC-1 tumors were administered the adenovirus, followed by the 5FU treatment. It was shown that the treatment with AxE1AdB-UPRT/5FU caused a dramatic reduction of the disseminated tumor burden without toxicity in normal tissues. These results revealed thatthe AxE1AdB-UPRT/5FU system is a promising tool for intraperitoneal disseminated pancreatic cancer.
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PMID:Gene therapy for pancreatic cancer targeting the genomic alterations of tumor suppressor genes using replication-selective oncolytic adenovirus. 1270 44

This paper overviewed risk factors of pancreatic cancer. Both genetic and environmental factors may be playing significant roles in the development of pancreatic cancer. Cigarette smoking has been established as a major risk factor for pancreatic cancer, based on findings from almost all epidemiological studies. Long-term smoking cessation may reduce the risk. The evidence that alcohol drinking and coffee consumption increase the risk is not sufficient, although an association with higher level of consumption remains a possibility. Diabetes mellitus, long-standing diabetes in particular, may be a risk factor for pancreatic cancer. Individuals with hereditary pancreatitis or non-hereditary chronic pancreatitis are possibly at increased risk of pancreatic cancer. Higher intake of meat and fat may be associated with an increased risk, while consumption of fruits/vegetables appears to have a protective effect. Individuals with mutations or deletion in such genes as K-ras, p16, p53, DPC4, and BRCA2 increased the risk of developing pancreatic cancer. Cigarette smoking may play a role in the development of these mutations.
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PMID:An Epidemiological Overview of Environmental and Genetic Risk Factors of Pancreatic Cancer. 1271 18

A frequent genetic alteration found in premalignant stages of pancreatic adenocarcinoma is K-ras oncogene point mutation. The mechanistic basis for the inability of K-ras mutation to transform pancreatic ductal cells is unclear, although cooperating events with p16 inactivation, p53 mutation, and SMAD 4 mutation are recognized to be necessary. We have generated a novel mouse model in which the cytokeratin 19 promoter, specifically active in pancreatic ductal cells but not other cell types of the pancreas, is fused to mutant K-ras. This is of direct relevance to human pancreatic cancer because premalignant lesions are found specifically in ductal cells. There is dramatic periductal lymphocytic infiltration in the pancreata of transgenic mice, predominantly CD4+ T lymphocytes, which may act as an adaptive immune response to activated ras-mediated signaling. In addition, gene array analysis reveals an induction of N-cadherin in transgenic mice pancreatic ductal cells, the significance of which relates to promotion of cell adhesion and deterrence of cell migration. Apart from these important biological considerations, there is parallel activity of the cytokeratin 19 promoter in the stem cell region of the gastric epithelium, namely in mucous neck cells. Activated K-ras in this context causes mucous neck cell hyperplasia, a precursor to gastric adenocarcinoma. There is concomitant parietal cell decrease, which is a key step toward gastric adenocarcinoma. Taken together, we have defined how mutant K-ras signaling modulates important molecular events in the initiating events of pancreatic and gastric carcinogenesis.
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PMID:The mutant K-ras oncogene causes pancreatic periductal lymphocytic infiltration and gastric mucous neck cell hyperplasia in transgenic mice. 1272 9

Laser microdissection is considered to be the gold standard of tissue sampling, especially if a defined small tissue area consisting of single or few cells within a heterogeneous tissue compartment is of interest. This sophisticated technique offers the opportunity of rapid and contamination-free tissue sampling for RNA- or DNA-based molecular genetic studies. We have applied laser microdissection to a molecular genetic study of pancreatic intraductal lesions (PanINs) in tissues of chronic pancreatitis, where an exact microdissection of small ducts within a dense fibrous tissue is of paramount importance for following analysis. From nine patients suffering from chronic pancreatitis, formalin-fixed, paraffin-embedded tissue specimens were laser microdissected, and a total of 202 normal ducts and PanINs of grade PanIN-1A to grade PanIN-2 were harvested. After whole genome amplification by improved primer extension and preamplification PCR (I-PEP-PCR), microsatellite-PCR based loss of heterozygosity analysis (LOH) of the tumor suppressor gene loci TP53, p16INK4, and DPC4 was performed. One of 85 informative duct lesions (1.2%) had LOH of TP53, 1 of 76 duct lesions (1.3%) had LOH of DPC4, and 2/29 duct lesions (6.9%) showed LOH of p16INK4. Microsatellite instability (MSI) was seen in 2 of 178 duct lesions (1.1%). Immunohistochemical staining of p53 protein and DPC4 protein revealed no aberrant expression. These preliminary data indicate that LOH of tumor suppressor genes, important in pancreatic cancer genesis or MSI, can be found in chronic pancreatitis tissues, but their incidence is low.
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PMID:Laser microdissection of small tissue samples--application to chronic pancreatitis tissues. 1292 36

The genetic basis for invasive and preoneoplastic neoplasms of the exocrine and endocrine pancreas has been the subject of a number of investigations in recent years. The purpose of this paper was to briefly review and summarize the pertinent findings. High frequency changes associated with pancreatic adenocarcinomas include mutations of the k-ras oncogene, and inactivating alterations of the p53, p16, and DPC4 tumor suppressor genes. Hereditary syndromes that have a known predisposition for pancreatic adenocarcinoma development include hereditary pancreatitis, familial atypical multiple mole melanoma (FAMM) syndrome, Peutz-Jeghers syndrome, familial breast cancer (BRCA-2), hereditary nonpolyposis colorectal cancer syndrome (HNPCC), and Li-Fraumeni syndrome. The underlying genetic defects have been identified and are currently being studied. Germline mutations of the men-1 gene are responsible for the MEN-1 syndrome, known to be associated with pancreatic endocrine tumors. It appears that somatic mutations of the gene are present in at least a subset of sporadic tumors. In addition, alterations in the Rb/p16 pathway appear to be commonly associated with pancreatic endocrine tumors. Further characterization of pancreatic tumors will result in a better understanding of the cellular pathways involved in pancreatic tumorigenesis and holds promise to identify targets for novel diagnostic and therapeutic strategies.
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PMID:The genetics of pancreatic cancer. 1294 33

Intraductal papillary neoplasms (IPNs) of the biliary tract are uncommon lesions that may be solitary or may spread extensively along the biliary tree. Some biliary IPNs are histologically and radiologically similar to intraductal papillary mucinous tumors (IPMNs) of the pancreas and present a risk for progression to invasive cholangiocarcinoma. Unlike pancreatic IPMNs, little is known about their molecular pathogenesis. We studied 14 biliary IPNs (including 5 cases with associated invasive cholangiocarcinoma) for genetic alterations in the APC/beta-catenin pathway, K-ras oncogene mutations, p53/chromosome 17p alterations, and Dpc4/18q alterations. Immunohistochemistry was performed for beta-catenin, p53, and Dpc4, and microdissected tissue was analyzed using direct DNA sequencing for exon 1 of K-ras and exon 3 of beta-catenin and allelic loss assays on chromosomes 5q, 17p, and 18q. Activating mutations in codon 12 of the K-ras oncogene were present in 4 of 14 (29%) biliary IPNs. Of these 4 cases, 2 patients had associated invasive cholangiocarcinoma, and identical K-ras mutations were present in both the intraductal and invasive components. Allelic loss on chromosome 18q was present in 4 of 13 informative cases (31%); however, no loss of normal Dpc4 expression was detected by immunohistochemistry. Nuclear accumulation of beta-catenin protein was demonstrated in 3 of 12 cases (25%); however, there were no beta-catenin gene mutations, and allelic loss on 5q was present in only 1 of 10 informative cases (10%). Both immunohistochemistry for p53 and 17p allelic loss assays were negative. Biliary IPNs therefore demonstrate a K-ras gene mutation frequency that is lower than that previously reported for pancreatic IPMNs, but similar to that reported for hepatic cholangiocarcinomas. The presence of K-ras mutations in 2 purely intraductal neoplasms, and identical K-ras mutations in 2 cases with both intraductal and invasive components, suggests that these mutations arise early in tumorigenesis. Finally, the frequency of allelic loss on 18q suggests that a locus on 18q is involved in the molecular pathogenesis of biliary IPNs, but this locus is not DPC4.
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PMID:Molecular and immunohistochemical analysis of intraductal papillary neoplasms of the biliary tract. 1456 86

Colorectal carcinomas develop according to particular genetic pathways, including the chromosomal instability (CIN+), microsatellite instability (MSI+) and MSI- CIN- routes. We have determined the genetic pathway in patients with MYH-associated polyposis (MAP), a syndrome of colorectal adenomas and cancer that results from defective base excision repair (BER). As in previous studies, MAP tumors showed a high frequency of G>T mutations in APC, in accordance with defective BER. We found that K-ras mutations were common in MAP tumors, all of the changes comprising conversion of the first guanine residue of codon 12 to thymidine (G12C, GGT>TGT). We found no BRAF mutations at the codon 599 hotspot or elsewhere in exon 14. Almost all of the MAP cancers were near-diploid (CIN-), and none was MSI+. A few p53 mutations were found, but these were not predominantly G>T changes. p53 overexpression was, however, frequent. No SMAD4 or TGFBIIR mutations were found. MAP tumors appear to follow a distinct genetic pathway, with some features of both the CIN and MSI pathways. BER deficiency is rarely accompanied by CIN or MSI. The spectrum of somatic mutations in MAP tumors reflects both selection and hypermutation to which certain guanine residues are particularly prone.
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PMID:Carcinogenesis in MYH-associated polyposis follows a distinct genetic pathway. 1463 73

Goblet cell carcinoid is a relatively rare neuroendocrine tumor of the vermiform appendix with poorly understood molecular pathogenesis. We studied the clinicopathologic features and genetic alterations, including allelic loss of chromosomes 11q, 16q, and 18q; sequencing of the K-ras, beta-catenin, and DPC4 (SMAD4) genes; and p53 overexpression and loss of DPC4 by immunohistochemistry; in 16 goblet cell carcinoids. We compared the allelic loss in goblet cell carcinoids to those in 18 gastrointestinal carcinoid tumors. For goblet cell carcinoids, appendiceal perforation was the most common (70%, 7/10) clinical presentation. The mean tumor size was 2.0 +/- 1.5 cm (range, 0.4 to 4.5 cm). The tumor invaded to appendiceal serosa in 50% (8/16) of patients, and two patients had metastasis in lymph nodes or adjoining viscera. With mean follow-up of 24 +/- 14 months (median, 23 mo), 1 of 10 patients had died of disease, and 2 others had tumor recurrence. All four patients with metastases, recurrences, and/or death from disease had serosal involvement at presentation (P =.02). Loss of heterozygosity of chromosome 11q was present in 25% of goblet cell carcinoids, 14% of ileal carcinoid tumors, and 9% of nonileal carcinoid tumors; of chromosome 16q in 38%, 29%, and 0 (P =.02); and of chromosome 18q in 56%, 86%, and 9% (P =.002), respectively. No mutations of K-ras, beta-catenin, or DPC4 genes; p53 overexpression; or loss of staining for DPC4 was present in any tumors. These findings suggest that allelic loss of chromosomes 11q, 16q, and 18q in goblet cell carcinoids and ileal carcinoids may have an important role in the pathogenesis of these tumors.
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PMID:Genetic alterations in goblet cell carcinoids of the vermiform appendix and comparison with gastrointestinal carcinoid tumors. 1468 18

Three cases of a distinctive intraductal tubular adenoma, pyloric type, of the main pancreatic duct are reported. The patients, two women and a man, whose ages ranged from 63 to 70 years, complained of abdominal pain attributed to chronic pancreatitis in two patients. The patient with the largest tumor also had symptoms of gastric outlet obstruction. The tumors, two of which arose in the head and one in the tail of the pancreas, led to occlusion and cystic dilatation of the main pancreatic duct. Two adenomas were sessile and one was attached to the wall of the pancreatic duct by a thin fibrous stalk. Microscopically, they were composed of lobules of closely packed tubular glands similar to pyloric glands. In one tumor, nearly all glands were lined by columnar mucin-secreting cells with abundant clear cytoplasm and basally oriented nuclei. In addition to pyloric glands, two adenomas contained glands lined by cells with little or no mucin as well as by pink oncocytic cells. Focal intestinal differentiation was identified in one tumor. Both intracellular and extracellular mucin was detected with the mucicarmine, periodic acid-Schiff, and alcian blue stains. All three adenomas were CK7 positive and CK20 negative. Focal carcinoembryonic antigen linear reactivity along the apical cytoplasm was seen in many cells, but few cells expressed cytoplasmic carcinoembryonic antigen. All three adenomas showed low proliferative activity as measured by the MIB-1 labeling index. The three adenomas were p53 negative and showed loss of DPC4 expression. No endocrine cells were identified in any of the tumors. All patients are alive and symptom free from 4 months to 5 years following surgical treatment.
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PMID:Intraductal tubular adenoma, pyloric type, of the pancreas: additional observations on a new type of pancreatic neoplasm. 1504 13

A large number of data derived from molecular analyses support the hypothesis that human cancer is a genetic disease and a distinct subset of genes have been found to be genetically changed in most tumors. Molecular alterations in pancreatic cancer include: (1) oncogenes such as K-ras, c-myc, c-fos, and c-erbB-2; (2) tumor suppressor genes such as p53, p16, DPC4/SMAD4, and DCC; and (3) growth factors such as EGF, FGF, HGF, PDGF, VEGF, TGF-beta. Genetic alterations of K-ras and p53 are common in human pancreatic cancer, but the occurrence of pancreatic cancer is a multi-step phenomenon in which the accumulation of genetic changes is extremely important.
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PMID:[Recent advances in gene change of pancreatic cancer]. 1505 82


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