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)

Topoisomerase I (topo I) is an important target for the treatment of malignant disease, especially colorectal cancer. Because there is little information on the expression of topo I in colorectal tumors, this study evaluated and characterized topo I protein expression in primary colorectal cancer and lymph node metastases and studied the association between topo I protein expression and clinicopathologic data, p53 status, and proliferating cell nuclear antigen (PCNA) status. Immunohistochemistry assay was performed for topo I protein expression in 249 primary human colorectal cancer and 42 paired lymph node metastasis samples. Topo I expression was described as the percentage of cells staining positive for topo I, along with the intensity and localization of the staining. Clinicopathologic data (sex, age, Dukes' stage, differentiation grade, survival status), p53 status, and PCNA status were statistically analyzed for association with topo I protein expression. Topo I expression in paired primary lymph node metastases were studied for concordance. Topo I protein expression was detected in 127 (51%) samples, including 24.4% with >50% positive tumor cells. The majority had nuclear (70.1%) or nuclear and cytoplasmic staining (17.3%). A higher percentage of cells expressing topo I in primary colorectal cancer was significantly associated with advanced age (P =.040). Patients with rectal cancer had greater topo I expression than those with colon tumors (P =.029). No significant correlation was found between topo I protein expression and sex, Dukes' stage, differentiation grade, survival status, p53 status, and PCNA status. Concordance in topo I staining between primary and lymph node metastases was observed in 33 of 42 cases (P =.029). This suggests that the activity of topo I inhibitors will not differ across various tumor stages, pathology, and patient gender. p53 and PCNA status do not appear to influence topo I expression, and topo I has no apparent association with the acquisition of a metastatic phenotype. Topo I expression now needs to be evaluated in patients undergoing topo I-inhibitor therapy, to better define the role of this protein as a predictive marker.
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PMID:Topoisomerase I protein expression in primary colorectal cancer and lymph node metastases. 1245 16

In recent years, numerous serum and cell/tissue-based markers have been described for colorectal cancer (CRC). The aim of this article was to provide guidelines for the routine clinical use of some of these markers. Lack of sensitivity and specificity preclude the use of any available serum markers such as carcinoembryonic antigen (CEA), CA 19-9, CA 242, CA 72-4, tissue polypeptide antigen (TPA) or tissue polypeptide-specific antigen (TPS) for the early detection of CRC. However, preoperative measurement of CEA is desirable as this may give independent prognostic information, help with surgical management and provide a baseline level for subsequent determinations. For patients with stage 2 (Dukes' B) and 3 (Dukes' C) disease who may be candidates for liver resection, CEA levels should be measured every 2-3 months for at least 3 years after diagnosis. For monitoring treatment of advanced disease, CEA should also be tested every 2-3 months. Insufficient evidence is presently available to recommend the routine use of other serum markers for monitoring purposes. Similarly, the new cell and tissue-based markers (e.g, ras, P53) cannot yet be recommended for routine clinical use.
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PMID:Clinical utility of biochemical markers in colorectal cancer: European Group on Tumour Markers (EGTM) guidelines. 1265 Nov 95

Mutations of the KRAS2 protoncogene and inactivation of the TP53 oncosuppressor gene have been suggested to contribute to chromosomal instability (CIN) and aneuploidy in colorectal cancer (CRC). Previous work has also shown that the degree of DNA ploidy [DNA index (DI)], as obtained by flow cytometry in CRC, is non-randomly distributed and, in particular, that DI near-diploid and near-triploid values are well separated by a low-probability valley region. At present, it is not known whether a relationship exists between DI and the mutational status of KRAS2 and TP53. Multiple samples obtained from 35 human sporadic CRCs have been used to provide nuclei suspensions for flow cytometric analysis and sorting of specific DI subpopulations. Sorted nuclei were then used to analyze the high-microsatellite-instability (MSI-H) phenotype and the mutation spectrum of the KRAS2 and TP53 genes. A single MSI-H case was detected. There were 6 DNA diploid (DI = 1) and 29 aneuploid (DI not equal 1) CRCs, with the DI aneuploid cases non-randomly subdivided in 9 near-diploid (DI not equal 1 and DI </= 1.4), 8 near-triploid (1.4 < DI < 1.6), and 12 high-aneuploid (DI >/= 1.6) cases. Proximal CRCs were more often DNA diploid and near-diploid than distal ones, and Dukes' C cases were more commonly high-aneuploid than Dukes' B. Moreover, the incidence of mutations of the KRAS2 and TP53 genes was lowest among the DNA near-triploid subpopulations and highest among the near-diploid ones. We suggest that DNA near-diploid and near-triploid subpopulations in human sporadic CRC reflect different genetic mechanisms of CIN and have a potentially different clinical behavior.
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PMID:Near-diploid and near-triploid human sporadic colorectal adenocarcinomas differ for KRAS2 and TP53 mutational status. 1269 70

PLK (polo-like kinase), the human counterpart of polo in Drosophila melanogaster and of CDC5 in Saccharomyces cerevisiae, belongs to a family of serine/threonine kinases. It is intimately involved in spindle formation and chromosome segregation during mitosis. The purpose of this study was to determine whether PLK1 is overexpressed in primary colorectal cancer specimens as compared with normal colon mucosa and to assess its relation to other kinases as a potential new tumor marker. In the present study, immunohistochemical analyses were performed of PLK1 expression in 78 primary colorectal cancers as well as 15 normal colorectal specimens. Furthermore, we examined the relationship between other kinases, Aurora-A and Aurora-C, and PLK1 expression. In normal colon mucosa, some crypt cells showed weakly positive staining for PLK1 in 13 out of 15 cases, the remaining cases being negative. Elevated expression of PLK1 was observed in 57 (73.1%) of the colorectal cancers, statistically significant associations being evident with pT (primary tumor invasion) (P=0.0006, Mann-Whitney U test), pN (regional lymph nodes) (P=0.008, chi2 test) and the Dukes' classification (P=0.0005, Mann-Whitney U test). Mean proliferating cell nuclear antigen-labeling index was 52.3%, with a range of 24.1% to 77.3%. Values for lesions with high and low PLK1 expression were 54.7+/-10.3% (mean+/-SD) and 45.9+/-11.9% (P=0.002, Student's t test). PLK1 was significantly associated with Aurora-A, but PLK1 staining was more diffuse and extensive than for Aurora-A or Aurora-C. Interestingly, PLK1 overexpression was significantly associated with p53 accumulation in colorectal cancers. Our results suggest overexpression of PLK1 might be of pathogenic, prognostic and proliferative importance, so that this kinase might have potential as a new tumor marker for colorectal cancers.
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PMID:Polo-like kinase 1 (PLK1) is overexpressed in primary colorectal cancers. 1270 89

The benefit of postoperative adjuvant chemotherapy in patients with Dukes' B colorectal cancer is still uncertain and its routine use is not recommended. Prognostic biomarkers may be useful for identifying high-risk patients with resected, node-negative disease, and this stratification may represent an innovative strategy for designing adjuvant chemotherapy trials. Featured prognostic molecular markers can be divided into the following categories: cell proliferation indices (Ki-67, Mib-1, proliferating cell nuclear antigen); oncogenes/tumor suppressor genes [p53, K-ras, Deleted in Colorectal Cancer (DCC), Bcl-2, c-erbB2]; DNA repair (microsatellite instability); markers of angiogenesis (vascular count, vascular endothelial growth factor); markers of invasion/metastasis (plasminogen-related molecules, matrix metalloproteinases); and biochemical markers (thymidylate synthase). Studies that have investigated their prognostic role in Dukes' B colorectal cancer patients are reviewed here. Current data do not provide sufficient evidence for the incorporation of available prognostic biomarkers into clinical practice. However, a biomarker-based approach could be an effective strategy for improving results of postoperative adjuvant treatments in high-risk Dukes' B colorectal cancer patients. Markers of altered DCC function have shown promising prognostic role and sufficient prevalence in retrospective investigations and they deserve further assessment in prospective studies.
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PMID:Prognostic molecular markers for planning adjuvant chemotherapy trials in Dukes' B colorectal cancer patients: how much evidence is enough? 1285 43

Differential microsatellite instability (MSI) in tumour epithelial and stromal compartments has not been well examined for colorectal cancers. Using laser-captured microdissection, separate specimens of these compartments of 40 sporadic colorectal cancers were sampled and MSI was tested with four markers. To examine the relation between the MSI phenotype in the stroma and other genetic events and histopathological features, p53 and K-ras gene mutations were analysed, and the expression of p53, hMLH1, and hMSH2 protein was determined by immunohistochemistry. Microsatellite instability positive results were obtained for both epithelium (34%) and stromal tissue (41%). While MSI in epithelium correlated with differentiation and Dukes' stage, that in stroma demonstrated an inverse relation, being particularly frequent in well-differentiated adenocarcinomas (54%) and Dukes' A lesions (55%). Further, a significant inverse correlation between p53 protein overexpression in the epithelium and MSI in the stroma was found (P=0.02475). The results suggest an alternative pathway of carcinogenesis involving stromal genetic instability in the development of colorectal cancers.
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PMID:Possible alternative carcinogenesis pathway featuring microsatellite instability in colorectal cancer stroma. 1291 83

The purpose of this study was (1) to disclose data from a non-randomized trial of prophylactic hepatic arterial chemotherapy for liver metastases from Dukes'C colorectal cancer, (2) to examine the influence of the expression of dihydropyrimidine dehydrogenase (DPD), thymidylate synthase (TS), and p53 in the primary lesion on this chemotherapy, and (3) to examine the expression of orotate phosphoribosyl transferase (OPRT) mRNA levels in the cases of recurrence included in this study. Patients who underwent curative resection of Dukes'C colorectal cancer between November 1996 and April 2000 were examined. After curative resection, patients were non-randomly divided into two groups after obtaining their informed consent: Hepatic arterial infusion (HAI) group patients (n = 28) were given 5-FU (500 mg/body for 1 h per week, repeated 50 times) via the hepatic artery and peroral UFT-E after resection of Dukes'C colorectal cancer. Control group patients (n = 21) received UFT-E alone. Liver metastasis-free survival did not differ between the groups. Immunohistochemical examinations revealed that the expression of tumoral DPD or p53 was unlikely to affect the hepatic recurrence, although patients with a low expression of TS tended to have better survival in both groups. However, multivariate analysis by the Cox proportional hazard model revealed that a significant prognostic factor influencing the hepatic recurrence is extensive venous invasion. Expression levels of OPRT mRNA, measured in tumors of patients with recurrence (n = 6 for the HAI group; and n = 4 for the control group) were not significantly different between the groups. These results suggest that (1) intermittent hepatic arterial infusion of 5-FU in addition to oral UFT-E was not more useful than administration of UFT alone, and (2) the expression of DPD, TS, p53, and OPRT in the primary lesion was unlikely to affect the prognosis of patients included in this study.
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PMID:[Results of prophylactic hepatic arterial chemotherapy for liver metastases of Dukes C colorectal cancer--correlation with tumoral expression of dihydropyrimidine dehydrogenase, thymidylate synthase, p53, or orotate phosphoribosyl transferase]. 1461 79

This study evaluates the potential ability of a specific panel of DNA mutations to identify right-sided colorectal carcinomas (CRCs) that would be missed by a flexible sigmoidoscopy (FS) screening program. This panel could then be applied to stool DNA analysis for noninvasive proximal CRC detection. A series of resected right-sided CRCs from 101 patients who had no left-sided advanced colonic neoplasms distal to the splenic flexure were analyzed. Tumor DNA was isolated from microdissected tumor sections. Deletions in the BAT-26 locus, a marker of microsatellite instability, and mutations at 19 loci spread among the p53, K-ras, and Apc genes were detected following PCR amplification. Mutations were identified in 83% of successfully amplified samples and were variably present in each of the target sites: p53 (42%), Apc (37%), K-ras (28%), and BAT-26 (24%). Mutations were identified across all Dukes stages (CIS/A 6/8 [75%], B 41/51[80%], C 30/32 (94%), and D 6/9 [67%]). Our data suggest that this 20-marker mutation panel may be associated with more than 80% of cancers undetectable by FS. The adjunctive use of stool DNA mutation analysis using this marker panel in FS CRC screening programs may significantly increase the detection of proximal CRC.
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PMID:Colon cancer-associated DNA mutations: marker selection for the detection of proximal colon cancer. 1463 4

A case-control study of Filipino patients who underwent surgical resection for colorectal cancer (CRC) during a 1-year period was undertaken. Thirty-five patients under age 40 years were identified. Paraffin blocks of these and 35 randomly selected patients over age 40 underwent histologic and immunohistochemical evaluation. Markers chosen for evaluation included the apoptosis-associated gene products (p53 and bcl-2), a tumor proliferation activity-related factor (Ki-67), and the markers (MLH1 and MSH2) of DNA microsatellite instability (MSI). Results were correlated with age and the stage and location of the tumor. The average age of the early-onset group was 30.7 years compared to the late-onset group at 67.0 years; and the male/female ratio was equivalent. The younger patients had a significantly higher Dukes' stage, the tumors were more poorly differentiated, and they were more frequently of the mucinous and signet ring cell histopathologic type. Expression of p53 was higher in the younger patients ( p < 0.001) and was independent of the degree of differentiation or the stage of the tumor. No differences of expression were noted for the other markers measured. The increased frequency of CRC in Filipino patients less than 40 years of age offers a unique opportunity to gain a better understanding of carcinogenesis, which might be exploited during diagnosis and management. The differences noted between the early- and late-onset CRC are provocative and provide an impetus for increased screening in Filipinos.
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PMID:Clinical and molecular biologic characteristics of early-onset versus late-onset colorectal carcinoma in Filipinos. 1470 47

Early detection of tumor DNA in serum/plasma prior to the development of recurrence or metastases could help improve the outcome of patients with colorectal cancer (CRC) after tumor resection. Recent advances in the detection of tumor DNA in the serum/plasma has opened up numerous new areas for investigation and new possibilities for molecular diagnosis. APC and K- ras mutations are considered to be early-stage developments of CRCs, whereas p53 mutations are thought to be relatively late events in the tumorigenesis of CRCs. The aim of this study was to search for the presence of genetic mutations in the DNA extracted from the serum of CRC patients and healthy subjects. We simultaneously evaluate the significance of APC, K- ras, and p53 gene mutations in cancer tissues and their paired serum samples of 104 CRC patients by polymerase chain reaction-single strand conformation polymorphism analysis (PCR-SSCP) followed by direct sequencing. Additionally, analysis was carried out to detect the serum carcinoembryonic antigen (CEA) levels in CRC patients. Overall, we found at least one of the gene mutations in tumor tissues from 75% (78/104) of the CRC patients. Comparison of the three molecular markers showed that the detection rates in the serum were 30.4%, 34.0%, and 34.2% for APC, K- ras, and p53 genes, respectively. Of these patients, 46.2% (36/78) were identified as having positive serum results, whereas all healthy controls remained negative. The overall positive tumor DNA detection rates in the serum were 0% (0/7) for Dukes' A classification, 22.4% (11/49) for Dukes' B, 48.7% (19/39) for Dukes' C, and 66.7% (6/9) for Dukes' D. The detection rate increased as the tumor stage progressed ( p = 0.012). Concurrently, a significant difference was observed between lymph node metastases and positive serum tumor DNA detection ( p < 0.001). A significantly higher postoperative metastasis/recurrence rate in patients harboring gene mutations with serum tumor DNA than those without serum tumor DNA was also demonstrated ( p < 0.001). However, no significant correlation between the postoperative metastasis/recurrence and serum CEA levels was observed ( p = 0.247). These data suggest that the identification of circulating tumor DNA using the molecular detection of APC, K- ras, and p53 gene mutations is a potential tool for early detection of postoperative recurrence/metastases. Moreover, these genes may be potential molecular markers of poor clinical outcome in CRC patients.
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PMID:Molecular detection of APC, K- ras, and p53 mutations in the serum of colorectal cancer patients as circulating biomarkers. 1518 2


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