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

Overexpression of p53-protein appears to be a common event in primary breast cancer. It has been proposed that the presence of elevated levels of this protein may be an independent prognostic factor and may be important for the ability of a tumor to metastasize. This study was performed to evaluate the influence of immunohistochemically detectable mutant p53-protein on metastasis-free survival of patients with breast cancer. Immunohistochemistry was performed on 117 paraffin-embedded biopsy specimens of consecutive patients with stage T1-T4 breast cancer, using a monoclonal antibody against p53 suppressor gene product. 29 (24.8%) specimens showed positive staining, whereas in 88 (75.2%) a negative staining reaction for p53 was found. Comparing time intervals to diagnosis of metastasis, using Kaplan-Meier curves, Log-Rank test revealed no significant differences in metastasis-free survival between p53 positive and negative patients (P = 0.32), whereas statistically significant differences were noted for tumor stage (P < 0.01), nodal status (P < 0.01), histological grading (P < 0.01) and estrogen receptor status (P = 0.03). Mutant p53-protein, as detected by immunohistochemistry in paraffin embedded tumor tissue, does not appear to influence metastasis-free survival in patients with breast cancer.
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PMID:Immunohistochemical detection of mutant p53-suppressor gene product in patients with breast cancer: influence on metastasis-free survival. 129 80

We examined 100 breast cancers for retinoblastoma (Rb) and p53 protein expression by immunohistochemistry using the PMG3.245 and PAb 1801 antibodies. We assessed percentages of reactive cells and their intensity, as well as staining patterns. The results were correlated with neu protein reactivity and a panel of variables, including age, tumor size and type, nuclear grade, estrogen receptor/progesterone receptor content, and lymph node status. Retinoblastoma protein negativity, either partial or complete, was noted in 47% of cases. Surprisingly, a relatively stronger Rb reaction was seen in some high nuclear grade tumors. p53 positivity was found in 23% of cases and was a significant predictor of Rb loss. p53 also was correlated with poorly differentiated (nuclear grade III) neoplasms and neu expression but not with negative ER status. Tissue distribution profiles for Rb-negative and p53-positive cells were variable in this series, with both uniform and heterogeneous patterns observed. This suggests that Rb and p53 alterations may represent early or late events in transformation. Our findings further implicate Rb and p53 derangements in mammary oncogenesis.
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PMID:Retinoblastoma and p53 gene product expression in breast carcinoma: immunohistochemical analysis and clinicopathologic correlation. 146 76

p53 protein has been frequently detected at high levels in the nuclei of human breast cancer cells. We analyzed immunohistochemically the association between nuclear localization of p53 protein and clinical and histological parameters of breast cancer patients. Surgically resected tissues of 73 primary breast cancers were processed by acetone fixation and paraffin embedding and examined using an anti-p53 monoclonal antibody, PAb1801. p53 immunoreactivity was detected in the nuclei of cancer cells in 17 cases (23%). The nuclear p53 immunoreaction was closely associated with overexpression of c-erbB-2 protein (P less than 0.05), high histologic grade (P less than 0.01), advanced clinical stage (P less than 0.05), and negative estrogen receptor status (P less than 0.01). When 31 cases which had been followed up for more than 50 months were examined, a positive nuclear p53 immunoreaction was found to be significantly associated with shorter overall survival of patients (P less than 0.01). These results suggest that immunohistochemical examination of nuclear p53 protein is clinically useful as an indicator of breast cancer aggressiveness.
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PMID:Nuclear p53 immunoreaction associated with poor prognosis of breast cancer. 167 56

Immunohistochemical evaluation of 200 primary breast cancers with the anti-p53 mouse monoclonal antibody (MAb) PAb421 showed positivity in nuclei of malignant cells in 31 cases (15.5%). PAb421+ cases were significantly more frequently epidermal growth factor receptor (EGF-R)-positive (67.7%; p less than 0.001) and estrogen receptor (ER)-negative (73.3%; p less than 0.001); they displayed surface histocompatibility class-1 (80.6%; p less than 0.01) and 11 (74.2%; p less than 0.05) antigens. Low values for progesterone receptor (mean 67.20 +/- 25.2 fmol/mg; p less than 0.05) and a high number of cells positive for the proliferation-associated antigen Ki-67 (log mean 6.88 +/- 0.33; p less than 0.01) were found in PAb421+ tumors as well as a high number of grade-3 infiltrating duct carcinomas (70%; p = 0.01). Of the 200 cases of mammary carcinoma, 88 were further analyzed using another human specific anti-p53 MAb PAb1801, and 40 (45.5%) were found positive. This MAb stained all the PAb421+ cases and was significantly associated with negative ER status (39.5%; p less than 0.05) and high Ki-67 scores (log mean 6.93 +/- 0.24; p = 0.001). Analysis of PAb1801+/Pab421- cases for HLA antigens, EGF-R and ER showed a phenotype similar to that of the p53-ve/ER+ carcinomas, except for the high Ki-67 score. No differences in age of the patient, number of involved nodes, tumor size, ploidy or labelling index scores were evident between p53+ and carcinomas. We concluded that p53 in mammary carcinomas is associated with ER-negative, growth factor receptor-positive, high-grade tumors, and is a promising new parameter to evaluate the cellular biology and prognosis of breast cancer.
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PMID:P53 expression in breast cancer. 327 32

Different variations of the antigen retrieval technique using different retrieval solutions have been evaluated for their effectiveness in restoring the antigenicity of six intranuclear antigens, each of which is a potentially valuable prognostic indicator in formalin-fixed, paraffin-embedded tissue sections. The results of immunohistochemical staining for estrogen receptor, progesterone receptor, androgen receptor, p53 protein, proliferating cell nuclear antigen, and Ki-67 antigen were compared following the different antigen retrieval approaches. The strongest immunostaining signal with the clearest background was obtained by microwave heating of dewaxed paraffin sections for 10 minutes in 0.05 mol/L glycine HCl (pH 3.5) or in citrate buffer solution (pH 6). Urea solution, distilled water, and lead thiocyanate solution yielded improvements with some antigens, but less consistently and less impressively than glycine HCl buffer or citrate buffer. Following antigen retrieval nuclear staining was sharply defined and could be achieved consistently in a variety of tissues after formalin fixation for as long as 7 days. The duration of fixation, however, was an important variable; generally, the longer the fixation time the more vigorous the retrieval procedure required. This study demonstrates the ability to stain a variety of intranuclear antigens, which are not readily demonstrable otherwise, in formalin-paraffin sections with a high degree of consistency and reproducibility. The availability of methods that are effective in paraffin sections may facilitate studies of the possible value of these markers as prognostic indicators for predicting the response of major tumors to different forms of therapy. This study also provided insight into the basic principles of the antigen retrieval method, which may be helpful in attempts to develop a more uniformly standardized technique applicable to many different antigen systems.
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PMID:Strategies for improving the immunohistochemical staining of various intranuclear prognostic markers in formalin-paraffin sections: androgen receptor, estrogen receptor, progesterone receptor, p53 protein, proliferating cell nuclear antigen, and Ki-67 antigen revealed by antigen retrieval techniques. 792 19

The present study compared two microwave based antigen-retrieval solutions in their ability to unmask antigenic determinants in formalin-fixed and paraffin-embedded tissues for Immunostaining. In this regard, two widely used antigen-retrieval solutions, namely 0.05 M glycine-HCl buffer, pH 3.6, containing 0.01% (w/v) (EDTA) and 0.1 M sodium citrate buffer, pH 6.0, were evaluated for (1) their effectiveness in unmasking a wide range of antigenic determinants (2) their ability to yield reproducible results (3) the lack of deleterious effects in any antibody antigen systems of interest. Both of these antigen-retrieval solutions resulted in greatly improved immunostaining following microwave-heating of dewaxed tissue sections for 2 x 5 min. Glycine-HCl buffer solution resulted in stronger immunostaining with antibodies to nuclear antigens [androgen receptor (AR), estrogen receptor (ER), progesterone receptor (PR), p53, proliferating cell nuclear antigen (PCNA), Ki-67 and MIB-1], cytoplasmic antigens (actin and factor-VIII) and cell-surface antigens [Cu-18, epithelial membrane antigen (EMA) and MT-1 (CD43)], whereas sodium citrate buffer yielded superior immunostaining with antibodies to vimentin, and some cell-surface antigens [common leukocyte antigen (CLA) (CD45) and UCHL-1 (CD45RO)]. The effect of unmasking the epitopes recognized by antibody to PCNA was equally effective with either of the antigen-retrieval solutions. Antibodies to pan-keratin, prostatic acid phosphatase (PAP), B lymphocyte antigen (BLA.36, CD20CY) and L26 (CD20) exhibited no enhancement in the intensity of staining with either of the antigen-retrieval solutions.
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PMID:Comparison of two microwave based antigen-retrieval solutions in unmasking epitopes in formalin-fixed tissue for immunostaining. 754 61

TP53 is a gene that normally regulates cell growth and division. Alterations to it may induce a proliferative advantage and confer an aggressive phenotype. In breast cancer, we observed a poor correlation (rs = 0.17) between P53 expression and proliferative activity evaluated as [3H]-thymidine ([3H]-dT) labeling index and an independent prognostic relevance of the two variables. We used a double-labeling technique to simultaneously evaluate the fraction of P53-positive and [3H]-dT-labeled cells to analyze the degree of association between the two markers on individual cells in order to understand their biological significance. The study was performed on a series of 44 P53-positive (P53+) breast cancers. Histological sections were immunostained for P53 with monoclonal antibody (MAb) PAb1801 and then processed for autoradiography. A weak direct relation between P53 positivity and [3H]-dT incorporation (rs = 0.4) was observed on the overall series of P53+ tumors and was maintained in subgroups defined by several biological and pathological features, except for estrogen receptor-negative tumors. The simultaneous presence of P53 expression and [3H]-dT incorporation was directly and significantly proportional to the fraction of S-phase cells of the tumor (rs = 0.7). Conversely, the fraction of cells expressing only P53 was inversely related to cell proliferation (rs = -0.66). These findings support the hypothesis that P53 has biological functions other than cell cycle regulation.
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PMID:Detection of P53 expression and S-phase cell fraction in paraffin-embedded tissue by a double-labeling technique. 756 Aug 90

P53 immunohistochemical detection using DO7 antibody on 942 cases of previously untreated breast invasive ductal carcinoma (IDC) with a median follow up of 117.9 months (89 to 160) was performed. Three hundred and three (32%) tumors were positive. All positive tumors were taken into account, positivity ranging from 1 to 100% of tumoral cells. The Chi square test showed significant negative correlation between p53 positivity and age (p = 0.01), estrogen receptor status (p < 0.0001), and progesterone receptor status (p = 0.0005), and significant positive correlation with tumor grade according to the Scarff, Bloom and Richardson system (SBR Grade) (p < 0.0001). There was no significant association with tumor size or nodal status. Concerning the univariate analysis, in the whole group and node-positive group (n = 544) p53 positivity was highly significant for overall survival (OS) (p < 0.0001 and p = 0.0003), disease-free interval (DFI) (p = 0.0001 and p = 0.0005), and metastasis-free interval (MFI) (p < 0.0001 and p = 0.0003). In the node-negative group (n = 398), p53 was significant with respect to OS (p = 0.01) and DFI (p = 0.04). P53 positivity came out as an independent prognostic parameter in the multivariate analysis in the whole group and the node-positive group, though of minor significance compared to axillary lymph node status, SBR grade, progesterone receptor status and tumor size.
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PMID:Prognostic value of p53 in breast invasive ductal carcinoma: an immunohistochemical study on 942 cases. 757 9

We evaluated the prognostic value of tumor angiogenesis in node negative breast cancer (NNBC). Paraffin-embedded tissues from 87 patients with NNBC were immunostained for factor VIII-related antigen, using one tissue block representative of the invasive edge of the tumor. Sections were scanned at low power to identify "hotspots" of angiogenesis. Microvessel (MV) counts were performed at x200 magnification, using a grid eyepiece graticule. Within each hot spot, three fields (area of field = 0.22 mm2) were counted and averaged. The highest average for a hot spot and the highest single field value was recorded for each case. Patients were stratified into low and high MV groups and their survival compared. There were no differences in disease-free or overall survival between the two groups whether the highest average or the highest single value was used. Microvessel counts did not correlate with other prognostic features, ie, grade, size, estrogen receptor status, c-erb B-2 or accumulated P53 status. Because of the difficulty in assessing angiogenesis that is heterogenous throughout tumors, MV counting may not be suitable for clinical use as a prognostic factor in NNBC. This problem could be addressed in a prospective study involving more extensive tumor sampling.
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PMID:Prognostic significance of microvessel density in lymph node negative breast carcinoma. 759 Jun 87

The retinoblastoma (RB) tumour suppressor gene has been associated not only with retinoblastoma but also with several other tumours like osteosarcoma, small cell lung carcinoma and prostate and breast cancer. We have studied the incidence of RB gene alterations in 96 primary breast tumours using Southern blotting techniques. The outcome has been related with patient and tumour characteristics, oncogene amplifications, p53 mutations and prognosis. RB gene alterations were found to occur more frequently in estrogen receptor (ER)-positive than in ER-negative tumours and less frequently in tumours with oncogene amplification than in tumours without oncogene amplification of HER2/neu, c-myc or 11q13. RB gene alteration was observed in tumours both with and without a p53 gene mutation. Data on 87 patients (mean age, 59.6 years; median follow-up, 108 months) and RB gene alterations revealed a significant association between the frequency of RB gene alterations and node-negative patients (p < 0.01) or smaller (< 2 cm) tumours (p < 0.01), but no relation with age, differentiation grade or (relapse-free) survival. Patients with and without RB gene alterations showed the same relapse-free and overall survival.
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PMID:Association between RB-1 gene alterations and factors of favourable prognosis in human breast cancer, without effect on survival. 761 56


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