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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

STAT proteins constitute a family of transcription factors whose activation by cytokine and non-cytokine receptors leads to tyrosine phosphorylation, dimerization and translocation from the cytoplasm to the nucleus. In the nucleus they activate the transcription of specific genes by binding to consensus DNA elements. STATs 1 and 3 can be activated by both cytokine and non-cytokine receptors, and bind as homodimers or heterodimers to viral simian sarcoma virus (sis)-inducible elements such as that found in the c-fos promoter. Activation of c-Src and EGF receptor tyrosine kinases is associated with progression of breast cancer. Both these events lead to activation of STAT proteins, Src kinases activate STAT3 dependent transcription in mammary epithelial cells and EGF receptor activation can lead to activation of STATs 1 and 3. STAT3 activation has been demonstrated to have a role in oncogenesis and increasingly, activated STAT proteins are found to be activated in human cancer. In this study we describe detailed immunohistochemical analysis of nuclear and cytoplasmic STATs 1 and 3 expression in primary breast carcinomas and correlate this with EGFR, HER2, p53, ER, PR, p21/waf1, Bcl-XL and Ki-67 expression. We also compared expression between normal and tumor tissue. We report here a highly significant correlation between nuclear STAT3 expression and breast cancers compared to normal tissue. We also report a very strong correlation between nuclear STAT3 and EGFR expression in breast cancers. These data clearly demonstrate a strong association between STAT3 activation and breast tumorigenesis and strengthen the assertion that STAT3 activation may play an important role in the tumorigenic conversion of breast tissue mediated by tyrosine kinase signaling pathways.
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PMID:EGFR dependent expression of STAT3 (but not STAT1) in breast cancer. 1171 84

Thus far, studies investigating the differences in tumour characteristics between breast cancer in BRCA1-carriers and other patients, have focused on highly selected groups of patients, potentially limiting the conclusions that can be drawn. Previously, we had identified 10 patients with BRCA1 germline mutations in a hospital-based series of 642 breast cancer patients not selected for age or family history. The aim of this analysis is to investigate the clinical and pathological features of these BRCA1 associated carcinomas as compared to other breast cancers in this representative sample. Tumours from patients with BRCA1 germline mutations (n = 10) were compared to an age-matched sample of other patients (n = 50) from the same cohort. The following characteristics were considered: axillary nodal status and tumour size, histologic parameters (tumour type, histologic grade, mitotic rate, tubule formation, nuclear grade, CIS and lymphangio invasion) and expression of several proteins (oestrogen and progesterone receptors, cyclin D1, p53, HER2/neu, E-cadherin). In BRCA1 associated tumours receptors for oestrogen and progesterone were expressed less frequently (respectively, P = 0.001 and P = 0.002) than in controls, which is in line with findings from other studies. Other differences were also in accordance with findings from other studies, although not statistically significant. We conclude that the features of BRCA1 associated tumours detected in a hospital-based series of breast cancer patients not selected for family history of age at diagnosis are similar to tumours in cases selected for family history or age at diagnosis.
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PMID:Clinical and pathological features of BRCA1 associated carcinomas in a hospital-based sample of Dutch breast cancer patients. 1172 Apr 73

One of the major challenges of early-stage breast cancer is to select the adjuvant therapy that ensures the most benefits and the least harm for the patient. The definition of accurate predictive factors is therefore of paramount importance. So far the choice of adjuvant therapy has been based on the number of affected lymph nodes and the hormone receptor status of the patient. This paper evaluates the use of other tumor-related markers as predictive factors for adjuvant therapy. These include HER2, p53 and Bcl-2, cathepsin B, p27, proliferating cell nuclear antigen (PCNA), cyclin D, Ki-67, and vascular endothelial growth factor (VEGF).
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PMID:Predictive factor for the response to adjuvant therapy with emphasis in breast cancer. 1173 86

Clinical responses to the HER1 (EGF receptor) inhibitors and HER2/neu/ErbB2 inhibitors correlate with high levels of receptor expression. However, a significant subset of patients with high receptor levels appear to be refractory to treatment. We have observed similar results in the 60 cell lines of the NCI Anti-Cancer Drug Screen using a panel of 11 selective HER1 inhibitors. As expected, low HER1-expressing cell lines were insensitive to HER1 inhibitors. In cell lines with high HER1 expression, low concentrations of HER1 inhibitors potently inhibit both HER1 phosphorylation and the mitogen-activated protein kinase (MAPK) pathway. However, this inhibition did not always correlate with cellular arrest. High HER1-expressing cell lines can be subdivided into two groups based on their sensitivity to HER1 inhibitors. In the sensitive group, receptor and growth inhibition was concordant and occurred at sub-micromolar concentrations of HER1 inhibitors. In the insensitive group, receptor inhibition occurred at a low concentration (< 1 microM) but concentrations that were ten times or higher were required for growth inhibition. Also, neither induction of p21 and cyclin D1 nor p53 status could explain the difference between sensitive and insensitive cells. Although EGF activated the MAPK pathway in all cell lines, only drug-sensitive cell lines responded to EGF (accelerated entry from G1 to S) and to HER1 inhibitors (G1 arrest) by changes in cell cycling. Furthermore, an EGF-dependent immortalized mammary epithelial cell line was extremely sensitive to a panel of HER1 inhibitors. We infer that independence from mitogen-mediated signaling confers insensitivity to HER1 inhibitors in a large subset of cancer cell lines.
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PMID:Differential sensitivity of cancer cells to inhibitors of the epidermal growth factor receptor family. 1179 Nov 82

Cyclooxygenase-2 (Cox-2) expression can induce mammary tumorigenesis in transgenic mice, and selective Cox-2 inhibitors are both chemopreventive and chemotherapeutic in rat models of breast cancer. We analyzed the expression of Cox-2 protein by immunohistochemistry in tissue array specimens of 1576 invasive breast cancers. Moderate to strong (elevated) expression of Cox-2 protein was observed in 37.4% of the tumors, and it was associated with unfavorable distant disease-free survival (P < 0.0001). Elevated Cox-2 expression was associated with a large tumor size, a high histological grade, a negative hormone receptor status, a high proliferation rate (identified by Ki-67), high p53 expression, and the presence of HER-2 oncogene amplification (P < 0.0001 for all comparisons), along with axillary node metastases and a ductal type of histology (P = 0.0001 and P = 0.0017, respectively). Interestingly, association with the unfavorable outcome was especially apparent in the subgroups defined by estrogen receptor positivity, low p53 expression, and no HER-2 amplification (P < 0.0001 for all comparisons). These results indicate that elevated Cox-2 expression is more common in breast cancers with poor prognostic characteristics and is associated with an unfavorable outcome. The present findings support efforts to initiate clinical trials on the efficacy of Cox-2 inhibitors in adjuvant treatment of breast cancer.
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PMID:Prognostic significance of elevated cyclooxygenase-2 expression in breast cancer. 1183 May 10

This study assesses the potential value of the tumor markers p53, HER2, and Bcl-2 in predicting the clinical response to doxorubicin and paclitaxel as single agents in the treatment of metastatic breast cancer. The primary tumors of 114 patients in the European Organization for Research and Treatment of Cancer 10923 trial were assessed by immunohistochemistry using monoclonal antibodies; the results were correlated with clinical response to therapy. HER2 was positive in 24% of patients, p53 was positive in 25% of patients, and Bcl-2 was positive in 49% of patients. There was no correlation between the expression of any of the markers and the clinical response to either agent. Although methodologically limited, this study does not support the use of p53, HER2, or Bcl-2 to assist the selection of anthracycline versus taxane in metastatic breast cancer.
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PMID:A study of the value of p53, HER2, and Bcl-2 in the prediction of response to doxorubicin and paclitaxel as single agents in metastatic breast cancer: a companion study to EORTC 10923. 1189 48

Fine needle aspiration cytology is central to the evaluation of clinically or mammographically detected suspicious lesions of the breast. On the basis of results from studies of >500 breast cancers by comparative genomic hybridization we have developed protocols and designed probe sets that allow one to visualize recurrent chromosomal aneuploidies, amplification of oncogenes, and deletion of tumor suppressor genes directly in cytological preparations using multicolor fluorescence in situ hybridization. The fluorescence in situ hybridization probes are specific for chromosome arm 1q, the c-MYC and HER2 oncogenes, the tumor suppressor gene p53 and, as controls for chromosome ploidy of each cell, the centromeres of chromosomes 8, 10, and 17. Application of these diagnostic mixtures to 20 invasive breast cancers, 7 mastopathias, and 2 fibroadenomas demonstrates that a highly sensitive, specific, and objective diagnosis of breast cancer is now possible on cytological preparations obtained by minimally invasive fine needle aspiration.
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PMID:Detection of chromosomal aneuploidies and gene copy number changes in fine needle aspirates is a specific, sensitive, and objective genetic test for the diagnosis of breast cancer. 1195 98

There is currently great interest in the detection and characterization of putative precursor breast cancer lesions because of the possibility of chemoprevention. Knowledge of the biologic features of premalignant lesions, although limited, is rapidly evolving. Premalignant breast lesions have been examined for the presence of genetic alterations and for the expression of biomarkers such as the estrogen receptor (ER), Ki67, p53, and HER2/neu. Data obtained from genetic studies of precursor breast lesions clearly support the contention that genetic alterations begin quite early in selected subsets of histologically benign lesions. Although the results of biomarker expression profiles have been contradictory, most studies agree that precursor lesions significantly overexpress ER and that progressive alterations in ER expression accompany the transition of normal cells to hyperplastic lesions and carcinoma in situ. So far, the collected evidence indicates that precursor lesions in the breast demonstrate biomarker expression profiles and genetic abnormalities that are distinct from those of terminal ductal lobular units but share some of these features with invasive tumors. Future research in this field is urgently needed to identify specific biomarkers of prognostic and predictive value, which can help not only in the selection of patients for chemopreventive therapy but in monitoring the progression of high-risk lesions.
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PMID:Molecular and biologic markers of premalignant lesions of human breast. 1198 Nov 14

In breast cancer the membrane expression of HER2 receptor protein encoded by the HER2 proto-oncogene seems to have an ever growing clinical significance. In tissue cultures and animal experiments it was shown that the HER2 gene amplification induces malignant transformation and intensifies the aggressiveness of the tumour cells. Correlating with the so called pheno-and genotypic prognostic markers, the overexpression of HER2 in breast cancer predicts also poor prognosis and indicates enhanced potential for metastatisation. In some of the so called precancerous proliferations and "in situ" carcinomas we demonstrated the enhanced membrane staining of the HER2 receptor protein. In these cases we frequently observed DNA aneuploidy,the presence of p53 mutational protein and CD44v6 glycoprotein. The immunohistochemical studies of HER2 protein in invasive carcinomas have revealed, an interrelationship between the grade of differentiation, histological type, aggressiveness and biological behaviour of the "in situ" and invasive carcinomas. In clinical studies trastuzumab, a humanized monoclonal antibody recognizing extracellular domain of HER2 receptor protein, has proved to be effective in HER2 overexpressing metastatic breast cancer either as monotherapy or in combination with chemotherapeutical agents. The DAKO "HercepTest" is a semiquantitative, standardised method for the determination of HER2 overexpression.
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PMID:[Expression of HER2 in breast cancer] 1205 Jul 66

OBJECTIVES: Characterization of breast cancers by various tumour markers which are appropriate for the identification of high risk groups. Markers related to the metastasis cascade and tumour recurrence have been investigated. MATERIALS AND METHODS: RT-PCR was used to determine the expression of cytokeratin 20 in the bone marrow and sentinel lymph node of breast cancer patients (n=45). The expression of HER2, Cadherin E, Cyclin D, Bcl2 and Bax has been evaluated by Western blot (n=744 invasive ductal carcinomas and 117 invasive lobular carcinomas, 124 recurrent breast cancers). Mutations of p53, APC and beta Catenin genes were detected by PCR-SSCP method. RESULTS: Expression of cytokeratin 20 was found in 30% of the bone marrow samples indicating the presence of micrometastasis. The level of Cyclin D, HER2 and Bcl2 is elevated four-fold in the recurrent breast cancers. The metastasis of invasive ductal carcinomas is accompained by high frequency of p53 mutations (24%) and APC mutations (18%). The invasive lobular carcinomas could be characterized with low frequency of p53 mutation (3%), low level of Cadherin E and high level of catenin beta. CONCLUSIONS: Identification of micrometastasis can promote the development of therapeutic strategy. Evaluation of HER2 level and determination of p53 mutations contribute to the identification of high risk patients. Our results suggest that the progression of invasive ductal carcinomas depends on the APC mutations, while metastasis of invasive lobular carcinomas depends on beta catenin mutations.
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PMID:[Prognostic factors of breast cancer] 1205 Jul 67


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