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)

Endometrial polyps and endometrial neoplasms are a recognized complication of chronic tamoxifen treatment. This study describes an endometrial carcinoma that developed in a woman receiving low-dose tamoxifen treatment for breast cancer. Little is known about steroid receptor status, somatic alterations in oncogenes and tumor suppressor genes, and inherited susceptibility in endometrial carcinomas associated with tamoxifen use. In the present case, the endometrial carcinoma was negative for estrogen receptors and weakly positive for progesterone receptors. In addition, analysis of K-ras, c-erbB2/neu, cyclin D1, and p53 status revealed a codon 12 point mutation in the K-ras oncogene. The patient was determined not to be a carrier of germ-line mutations in cytochrome P-450 1A1 (CYP1A1), an estrogen-metabolizing gene previously associated with enhanced endometrial cancer risk, but she was a carrier of a methylenetetrahydrofolate reductase gene variant related with putative alterations in DNA methylation.
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PMID:Endometrial carcinoma in tamoxifen-treated breast cancer patient: clinicopathological, immunohistochemical, and genetic analysis. 1054 49

The new anticancer agent poly(L-glutamic acid)-paclitaxel (PG-TXL) is a conjugate of paclitaxel and the water-soluble polyglutamate carrier. The observation that PG-TXL appears to possess antitumor activity superior to free paclitaxel in preclinical studies suggests that PG-TXL might possess favorable pharmacokinetic properties and/or have a mechanism of action different from that of paclitaxel. The purpose of this study was to compare the pharmacological action of PG-TXL and free paclitaxel in a panel of breast cancer cell lines with emphasis on their ability to induce apoptosis, their effects on cell cycle progression, and their cellular uptake. Morphological analysis and biochemical characterizations demonstrated that both compounds have similar abilities to induce apoptosis in cells expressing wild-type p53 (MCF-7) or mutant p53 (MDA-MB435 and MDA-MB453). Although MCF-7 cells were less sensitive to each compound than MDA-MB435 and MDA-MB453 cells, transfection experiments demonstrated that p53 did not appear to play a significant role in drug-induced cell death with either agent. Flow cytometry analysis further revealed that both free paclitaxel and PG-TXL induced a characteristic G2/M arrest in the cell cycle, consistent with the disturbance of microtubule polymerization as their mechanism of action. Western blot analysis showed that paclitaxel and PG-TXL downregulated HER2/neu expression in a similar fashion. HPLC analysis revealed that paclitaxel was released from the PG-TXL conjugate in vitro. The released paclitaxel, not the glutamic acid polymer, was subsequently transported into the cells. These results suggest that PG-TXL exerts its anticancer activity by continuous release of free paclitaxel, and that the favorable pharmacokinetics and drug distribution of the PG-TXL conjugate in vivo are likely the main factors contributing to its superior anticancer activity.
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PMID:Comparison of action of paclitaxel and poly(L-glutamic acid)-paclitaxel conjugate in human breast cancer cells. 1060 57

Using immunohistochemistry, expression of p53, transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGFR), c-erbB-2/neu and proliferating cell nuclear antigen (PCNA) was examined in 26 fresh frozen tissue specimens of oropharyngeal squamous cell carcinomas (SCCs). p53 gene mutations were examined by polymerase chain reaction (PCR)/DNA sequencing methods in 22 carcinomas. The findings were examined for correlations with patients' clinicopathological parameters. Expressions of p53 and PCNA were also examined in 21 formalin-fixed corresponding tissues. Of the fresh frozen tissue specimens, 77% (20/26) showed expression and 68% (15/22) showed mutations (substitutions) of the p53, with significant clustering of the mutations in exons 5 (8/22; 36%), 7 (4/22; 18%) and 8 (5/22; 23%). No mutations were found in exon 6. There was a discordance between expression of p53 protein and mutations of the gene. Parallel to expression and mutations of the p53 found in most of the specimens, expression of TGF-alpha, EGFR, c-erbB-2/neu and PCNA was found in 88% (22/25), 92% (23/25), 58% (14/24) and 91% (21/23) of the specimens, respectively. For the formalin-fixed tissue specimens, 62% (13/21) and 90% (19/21) expressed p53 and PCNA, respectively. Examining for correlations with patients' clinicopathological parameters, expression of p53, TGF-alpha, EGFR and c-erB-2/neu seemed to negatively correlate with the increase of the tumour grade. The present work suggests that: (1) lack of negative growth regulation due to inactivation of the p53 gene together with activation of other proto-oncogenes are necessary genetic events in the carcinogenesis of oropharyngeal SCCs; (2) in oropharyngeal SCCs, p53 gene mutations were clustered in exons 5 (codons 130-186), 7 (codons 230-248) and 8 (codons 271-282) which perhaps suggests that tobacco carcinogens probably affect the mutational hot spots of the p53 gene at codons 157, 175, 186, 248, 273 and 282; and (3) fresh frozen and formalin-fixed tissue specimens give similar results when an immunohistochemical method is applied. The importance of p53, TGF-alpha, EGFR, c-erbB-2/neu and PCNA as biomarkers in oropharyngeal SCCs deserves particular attention because it might offer further understanding of the development of these carcinomas.
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PMID:Expression of biomarkers (p53, transforming growth factor alpha, epidermal growth factor receptor, c-erbB-2/neu and the proliferative cell nuclear antigen) in oropharyngeal squamous cell carcinomas. 1062 52

Human solid tumors develop multiple genetic abnormalities that accumulate progressively in individual cells during the course of tumor evolution. We sought to determine whether there are specific sequences of occurrence of these progressive evolutionary changes in human breast cancers by performing correlated cell-by-cell measurements of cell DNA content, p53 protein, Her-2/neu protein, and ras protein by multiparameter flow cytometry in 56 primary tumor samples obtained at surgery. In addition, p53 allelic loss and Her-2/neu gene amplification were determined by fluorescence in situ hybridization in cells from the same samples. We reasoned that if there is a specific order in which genetic changes occur, the same early changes would be found consistently in the cells with the fewest abnormalities. We reasoned further that late-developing abnormalities would not occur alone in individual cells but would almost always be found together with the early changes inherited by the same cells. By these criteria, abnormalities involving p53 generally occurred early in the course of development of invasive breast cancers, whereas ras protein overexpression was found to be a late-occurring phenomenon. Within individual tumors, cellular p53 overexpression was often observed alone in individual cells, whereas ras protein overexpression was rarely observed in the absence of p53 overexpression and/or Her-2/neu overexpression in the same cells. Furthermore, the intracellular level of each abnormally expressed protein was found to increase progressively as new abnormalities were acquired. Infiltrating ductal carcinomas exhibited characteristic phenotypic patterns in which p53 allelic loss and/or p53 protein overexpression, Her-2/neu amplification and/or overexpression, aneuploidy, and ras overexpression accumulated within individual cells. However, this pattern was not a prominent feature of lobular breast cancers. All six lobular breast cancers studied were diploid. p53 allelic loss and/or early p53 overexpression, and late ras cooverexpression in the same cells were less common in lobular breast cancers than in infiltrating ductal carcinomas. Although Her-21neu overexpression was a common finding in lobular breast cancers, Her-2/neu amplification was not observed in these tumors.
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PMID:Correlations among p53, Her-2/neu, and ras overexpression and aneuploidy by multiparameter flow cytometry in human breast cancer: evidence for a common phenotypic evolutionary pattern in infiltrating ductal carcinomas. 1065 39

A number of approaches have been used to identify genes important in breast cancer. In one approach the genes already shown to be involved in other tumors, such as p53 and Her2neu, were examined. A second approach examined genes detected through genetic screening of families with a high incidence of breast cancer, for example, BRCA-1 and BRCA-2. We used a third approach, subtractive hybridization, to identify and clone genes that were preferentially expressed in breast cancer cells compared to normal mammary epithelium. Instead of analyzing breast cancer cell lines, we examined fresh human breast cancer specimens. By subtracting normal mammary epithelial cDNA from breast cancer cDNA, we were able to clone several genes overexpressed in breast cancer. Two of these genes, L19 and MLN70, were previously reported to be overexpressed in breast cancer. Three of these genes, L19, L34, and MLN70, were localized to a region on chromosome 17 where Her2/neu and BRCA-1 are found. In addition, we isolated a gene we call breast cancer associated gene-1 that was expressed almost exclusively in fresh breast cancer tissue and not in normal mammary epithelium or breast cancer cell lines. We were unable to detect expression of breast cancer associated gene-1 in cell lines from melanoma, renal cell carcinoma, lymphoma, or leukemia. The full-length sequence from two separate breast cancer specimens revealed one amino acid difference compared to the sequence from normal breast epithelial tissue. Further studies are necessary to determine whether these genes contribute to breast cancer development or can be used as therapeutic targets.
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PMID:Isolation of genes overexpressed in freshly isolated breast cancer specimens. 1075 78

Selection of surrogate endpoint biomarkers (SEBs) and appropriate study design are two of the main challenges in evaluating potential chemopreventive agents. In a prospective random fine-needle aspiration (FNA) study of women at high risk of development of breast cancer, we previously demonstrated that cytologic evidence of epithelial hyperplasia with or without atypia, as well as abnormalities of several cellular biomarkers (DNA ploidy; immunocytochemical expression of p53, EGFR, ER, and/or Her-2/neu), were more prevalent in high-risk women than in low-risk controls. We also demonstrated that the subsequent development of breast cancer was best predicted by an initial presentation of hyperplasia with atypia, as well as by multiple biomarker abnormalities. These findings indicate that FNA cytology and biomarkers can be used to identify women who are appropriate subjects for chemoprevention trials, and can then be used as surrogate endpoint biomarkers to monitor efficacy of potential agents. An example of this use in an ongoing single-agent phase II trial is provided. Several options for study design of possible multi-agent breast cancer chemoprevention trials are discussed, depending upon the existing preclinical and clinical data, the questions being asked, and the number of eligible subjects available.
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PMID:Breast cancer chemoprevention trials using the fine-needle aspiration model. 1076 8

Cell lines are valuable resources for the study of the malignancy and potential therapy of human breast cancer. A major problem with adapting fresh breast tumor specimens to grow in vitro is contamination by fibroblasts. Previously, we have reported a technique to overcome this problem (Nayak, S. K; Dillman, R. O. Clin. Biotechnol. 3:237-242; 1991). We have recently established two new breast cancer cell lines, HH315 and HH375, that were derived from abdominal and supraclavicular lymph node metastases from two patients. They were characterized by (1) growth kinetics; (2) staining with monoclonal antibodies (MoAbs) to cytokeratin-19, epithelial membrane antigen (EMA), anticarcinoembryonic antigen (CEA), breast cancer antigen 1 (BRST-1), breast cancer antigen 2 (BRST-2), Her2/neu, and p53; (3) expression of domains of urinary plasminogen activator (uPA), neural cell adhesion molecule (NCAM), and haptoglobin (Hp) (Harvey et al., 1997); and (4) karyotypic analysis. Growth kinetic studies showed that doubling times for both lines ranged from 48 to 96 h. These two cell lines were found to have characteristics of the metastatic breast cancer cells. Both lines stained positive with MoAbs to cytokeratin-19 and EMA, thus confirming their epithelial origin. They also strongly reacted with the pan-breast carcinoma MoAbs BRST-1 and BRST-2, and carcinoembryonic CEA MoAb. Both cell lines overexpressed the oncogene proteins Her2/neu and p53. The tumor cells were negative for estrogen and progesterone receptors. HH315 cells were poorly differentiated, whereas the HH375 cells exhibited adenocarcinoma morphology. Both cell lines showed intense cell surface and some cytoplasmic staining for uPA, NCAM, and Hp domains, which is a characteristic of malignant neoplasms (Harvey et al., 1997). The HH375 cell line showed two cell types, of which 60% were hyperdiploids with 60-70 chromosomes and 5-10 marker chromosomes. The remaining cells were polyploid with more than 200 chromosomes. Cell line HH315 consisted of only a polyploid population. These cell lines may be useful in breast cancer research.
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PMID:Characterization of cancer cell lines established from two human metastatic breast cancers. 1077 59

Pancreatic cancer is a lethal disease characterized by local invasion and early dissemination. It is resistant to conventional surgical, radiotherapeutic, and chemotherapeutic modalities. These interventions have had minimal impact on overall survival with very few patients enjoying long term survival. Over the past few years, 2'difluoro-2'deoxycytidine (gemcitabine) has demonstrated modest activity in this disease and investigations are proceeding to expand its role in combination with radiotherapy and other chemotherapeutic agents. In addition, the identification of the molecular defects underlying this disease has suggested molecular targets for the design of rational systemic therapy. These targets include matrix metalloproteinases, K-ras, HER2/neu, p53, and the epidermal growth factor receptor. Current and future clinical trials designed to improve the survival of patients with pancreatic cancer will be discussed.
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PMID:Current approaches and future strategies for pancreatic carcinoma. 1083 Jan 40

Breast cancer is an etiologically heterogeneous disease with marked geographical variations. Joint consideration of the relationship between specific molecular alterations and known or suspected epidemiologic risk factors for this disease should help distinguish subgroups of women that are at elevated risk of developing breast cancer. In this article, we present a comprehensive literature review of the etiologic and prognostic roles of Her-2/neu and P53 among women. In addition, we discuss the advantages and limitations of using biomarkers in epidemiological studies. We conclude that more research is needed to understand the complex relationships between genetic alterations and etiologic risk factors for breast cancer.
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PMID:The epidemiology of Her-2/neu and P53 in breast cancer. 1085 Jan 34

Peptides presented by class I major histocompatibility complex (MHC) molecules and derived from normal self-proteins that are expressed at elevated levels by cells from a variety of human (Hu) malignancies provide, in theory, potential target antigens for a broad-spectrum, cytotoxic T lymphocyte (CTL)-based immunotherapy of cancer and hematologic malignancies. However, as such tumor- and leukemia-associated self-proteins are also expressed at low levels in some types of normal tissues, such as thymus, spleen and lymphohemopoietic cells, these self-MHC-self-peptide complexes may also represent thymic and/or peripheral tolerogens, thereby preventing immune responses. This is particularly true for class I MHC-peptide complexes expressed by bone marrow-derived cells in the thymus, as such expression would cause negative selection of immature thymic T cells with high avidity for self-MHC-self-peptide complexes. This intrathymic deletion of potentially self-reactive T cells could result in a peripheral T cell repertoire purged of CTL precursors with sufficient avidity to recognize natural tumor associated self-epitopes presented by class I MHC molecules on tumor cells. HLA-transgenic (Tg) mice provide the basis of an experimental strategy that exploits species differences between Hu and murine (Mu) protein sequences in order to circumvent self-tolerance and obtain HLA-restricted CTL specific for epitopes derived from tumor- and leukemia-associated Hu self proteins, such as p53, Her-2/neu, hdm2 and CD19.
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PMID:Targeting p53, hdm2, and CD19: vaccination and immunologic strategies. 1093 87


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