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

Bloom syndrome (BS) is a rare autosomal recessive genetic disorder characterized by lupus-like erythematous telangiectasias of the face, sun sensitivity, stunted growth infertility and immunodeficiency. In addition, BS patients are highly predisposed to cancers. Although recently the causative gene of BS (BLM) was identified as a DNA helicase homologue, the function of BLM in DNA replication has not been elucidated. In this study, p53 mutation and microsatellite instability in B-cell lymphomas originating from 2 sibling BS patients were investigated. In the originally developed tumor of both patients, no p53 mutation was detected. In one patient, however, after treatment by ionizing radiation the B-cell lymphoma recurred, showing a 9-bp deletion in exon 7. In lymphoma cells and an EB-virus-transformed cell line from BS lymphocytes of this patient, microsatellite instability was also detected from the reduced length of microsatellite DNA markers, although in the other patient microsatellite instability was not detected. Thus, 2 B-cell lymphomas, despite having the same BLM mutation, showed different phenotypes in terms of p53 mutation and microsatellite instability.
 ...
PMID:Microsatellite instability in B-cell lymphoma originating from Bloom syndrome. 898 Feb 51

The study was aimed to detect differences in nuclear morphology between nuclear populations as well as between tumours with different p53 expression in breast cancers with different clinicopathological features, which also reflect the stage of tumour progression. The p53 immunohistochemistry was performed on paraffin sections from 88 tumour samples. After the cells had been localised by means of an image cytometry workstation and their immunostaining had been categorised visually, the sections were destained and stained by the Feulgen protocol. The nuclei were relocated and measured cytometrically by the workstation. There were significant differences in the nuclear features between tumours as well as between nuclear populations with different p53 expression in the most subgroups. The variability of nuclear shape in tumour groups, classified by the tumour size or the lymph node status, increase with the p53 immunoreactive score, whereas in tumours grouped by the Bloom-Richardson grade features of the chromatin distribution were different between the p53 staining categories. The nuclear subpopulations showed differences in the amount and distribution of chromatin in most subgroups. The results demonstrate the relationship between the nuclear morphology and the p53 expression in different stages of breast cancers. The p53 status is an important factor of the biological behaviour but not the only one.
 ...
PMID:Morphological heterogeneity of p53 positive and p53 negative nuclei in breast cancers stratified by clinicopathological variables. 931 26

Bcl-2 has been demonstrated to inhibit apoptosis in breast cancer cells in vitro, and the ratio between Bcl-2 and its proapoptotic homologue Bax seems to be an important determinant of cellular sensitivity to induction of apoptosis. However, little information is available on the relationship between Bcl-2 and the rate of apoptotic and necrotic cell death in breast tumours. From a series of 441 premenopausal, lymphnode-negative breast cancer patients, a subset of 49 tumours was selected in which immunostaining for the 26-kDa isoform of Bcl-2 was either absent (n = 23) or very high (n = 26). High expression of Bcl-2 was found to be strongly associated with low rates of apoptotic (P < 0.001) and necrotic cell death (P < 0.001). The mean value of the apoptotic index was 2.69%+/-1.40% in Bcl-2-negative tumours and 0.68%+/-1.00% in Bcl-2-positive tumours. Expression of the proapoptotic protein Bax correlated neither with Bcl-2 nor with the frequency of apoptotic cells. Immunostaining for the antiapoptotic Bcl-2 homologue BcI-X(L) correlated with Bcl-2 expression (P < 0.001) but not with apoptosis. High proliferation rate and high tumour grade (Bloom-Richardson) were strongly associated with absence of Bcl-2 expression (P< 0.001). p53 accumulation was associated with absence of Bcl-2 expression and increased apoptotic activity. Loss of Bcl-2 expression was strongly correlated with increased apoptotic and necrotic cell death, high proliferation rate and high tumour grade, supporting a model in which Bcl-2 not only mediates cell death, but also cell division in breast cancer tissue, and in which regulation of cell division and cell death are tightly linked.
 ...
PMID:Loss of Bcl-2 in invasive breast cancer is associated with high rates of cell death, but also with increased proliferative activity. 951 59

Abnormalities precipitated by a targeted truncation in the murine gene Brca2 define its involvement in DNA repair. In culture, cells harboring truncated Brca2 exhibit a proliferative impediment that worsens with successive passages. Arrest in the G1 and G2/M phases is accompanied by elevated p53 and p21 expression. Increased sensitivity to genotoxic agents, particularly ultraviolet light and methylmethanesulfonate, shows that Brca2 function is essential for the ability to survive DNA damage. But checkpoint activation and apoptotic mechanisms are largely unaffected, thereby implicating Brca2 in repair. This is substantiated by the spontaneous accumulation of chromosomal abnormalities, including breaks and aberrant chromatid exchanges. These findings define a function of Brca2 in DNA repair, whose loss precipitates replicative failure, mutagen sensitivity, and genetic instability reminiscent of Bloom syndrome and Fanconi anemia.
 ...
PMID:Involvement of Brca2 in DNA repair. 966 Sep 19

The Bloom's syndrome gene, BLM, encodes a protein which bears homology to the RecQ helicases. It is believed to be involved in DNA replication and has been implicated in the maintenance of genomic stability. To investigate whether BLM was involved in cellular responses to DNA damage Bloom's syndrome fibroblasts were treated with either UV or ionizing radiation and the levels of p53 and two of its down stream effectors, p21waf1/cip1 and hdm2, were determined by western blot analysis. Following 20 J/m2 UVC-radiation we observed that the maximal accumulation of p21waf1/cip1 and hdm2 proteins preceded that of p53 in both a normal diploid fibroblast cell strain (GM0038) and in two Bloom's syndrome cell strains. Furthermore, the Bloom's syndrome cells demonstrated a delayed and prolonged accumulation of all three proteins and a delayed recovery of the protein levels back to pre-damage levels compared with the normal cell strain. Conversely, normal and Bloom's syndrome cell response following 2.5 Gy of ionizing radiation was quite similar for p21waf1/cip1 and hdm2, but differed significantly for p53. Maximum accumulation of p53 occurred within 2 h of damage and preceded that of p21waf1/cip1 and hdm2. These results suggest that the BLM protein may play a role in the detection of certain types of DNA damage and in the cellular response to that damage.
 ...
PMID:Differential expression of p53, p21waf1/cip1 and hdm2 dependent on DNA damage in Bloom's syndrome fibroblasts. 988 65

The classification of histological malignancy by Bloom and Richardson used in ductal invasive breast cancer seems to be not sufficient. In the same group of patients with the same clinical status as well as pathological malignancy the prognosis can be different and unpredictable. The aim of the study was to examine a consecutive series of primary ductal invasive tumours to find out: a) the expression of some biological cellular parameters as proliferating antigens Ki67 and PCNA and the products of the suppressor gene p53; b) the correlation between the levels of expression of those factors and classical prognostic factors, such as tumour diameter, status of axillary lymph nodes, status of steroids receptors, degree of histological differentiation. It seems that the estimation of proliferating antigens together with products of suppressor gene p53 might have greater prognostic value than the estimation of single factors.
 ...
PMID:The expression of the proliferating antigen Ki67, PCNA and products of suppressor gene p53 in primary invasive ductal breast carcinoma. 1008 75

A 17-year-old Turkish boy with Bloom syndrome (BS) developed mucinous carcinoma of the transverse colon. He was followed from 2 to 17 years of age. Increased sister chromatid exchanges (SCE) were observed, and he was diagnosed with BS at the age of 7. Sun-sensitive skin lesions were examined by skin biopsy, and histopathological studies of these lesions were done. During the follow-up period, an intraabdominal mass at the transverse colon was found, and mucinous carcinoma of colon was diagnosed at the age of 16. We examined TP53 protein expression from paraffin-embedded colon tissue of the patient with an immunohistochemical method. Polymerase chain reaction products of exons 4-9 of the TP53 gene were examined by SSCP. No evidence of overexpression of TP53 protein or mutations of the TP53 gene was observed. The patient in this report is the first case with a mucinous carcinoma of colon diagnosed at an early age in the Bloom Syndrome Registry. Based on our results, carcinoma of the colon in BS patient may occur earlier than 35 years of age and the TP53 gene may not be directly related to carcinoma in Bloom syndrome.
 ...
PMID:Mucinous carcinoma of the colon in a 16-year-old Turkish boy with Bloom syndrome: cytogenetic, histopathologic, TP53 gene and protein expression studies. 1032 90

Infiltrating micropapillary carcinoma of the breast is a recently described and poorly recognized aggressive variant of infiltrating ductal carcinoma for which the clinical significance and role of prognostic markers are not fully described. In 14 cases of infiltrating micropapillary carcinoma, we studied histologic characteristics; immunohistochemical expression of c-erbB-2, p53, and MIB-1; hormonal expression of these tumors; and genetic alterations on the p53 locus. We correlated these results with clinical outcome. Patient ages ranged from 37 to 58 years (mean, 50 yr). Nine patients presented with a palpable tumor, one with an axillary mass. Three patients had abnormal mammograms. Five patients (36%) presented with Stage II disease, eight (57%) with Stage III, and one (7%) with Stage IV. The tumors were a modified Bloom-Richardson Grade II in nine cases (64%) and Grade III in 5 (36%). Mitoses ranged from 1 to 12 per 10 high power fields. Necrosis was uniformly absent. Psammoma bodies were present in 9 cases (64%) and lymphatic invasion in 10 (71%). In all of the cases, c-erbB-2 was identified immunohistochemically, and MIB-I was positive, staining 30 to 60% of the tumor cells. The cells were immunoreactive for p53 in six (75%) of eight cases, and, when present, stained 20 to 50% of the tumor cells. Loss of heterozygosity on locus 17p13.1 (p53) was identified in 4 of 5 informative samples. Molecular and immunohistochemical analyses had an 80% concordance. Follow-up was available in 11 patients, of whom 9 had recurrence in the skin and chest wall (average time of recurrence, 24 mo). Recognition of this distinctive and aggressive variant of infiltrating carcinoma is important because of its unfavorable prognosis and specific pattern of local recurrence. Its aggressive nature is supported by its advanced stage at presentation and expression of unfavorable prognostic markers.
 ...
PMID:Infiltrating micropapillary carcinoma of the breast. 1034 88

The WRN DNA helicase is a member of the DExH-containing DNA helicase superfamily that includes XPB, XPD, and BLM. Mutations in WRN are found in patients with the premature aging and cancer susceptibility syndrome known as Werner syndrome (WS). p53 binds to the WRN protein in vivo and in vitro through its carboxyl terminus. WS fibroblasts have an attenuated p53- mediated apoptotic response, and this deficiency can be rescued by expression of wild-type WRN. These data support the hypothesis that p53 can induce apoptosis through the modulation of specific DExH-containing DNA helicases and may have implications for the cancer predisposition observed in WS patients.
 ...
PMID:p53-mediated apoptosis is attenuated in Werner syndrome cells. 1036 53

GM1492 human diploid skin fibroblasts derived from a patient with Bloom's syndrome (BS), lack detectable p53 mRNA and protein as shown by Northern and Western blotting, and express an increased RecA-like activity. Here we demonstrate that the p53 gene is grossly intact in GM1492 cells according to Southern blotting. DNA sequencing did not reveal any mutations in the promoter region of p53. A highly sensitive RT-PCR produced a p53 cDNA fragment that was shorter than expected. DNA sequence analysis of p53 cDNA showed that exon 6 was missing, explaining the shorter PCR product. Furthermore, sequencing of genomic DNA revealed a base substitution at the nucleotide preceding the AG splice acceptor site of intron 5. The omission of exon 6 creates a frameshift at the junction of exons 5 and 7, and a premature stop codon in exon 7. The aberrant transcript is predicted to encode a truncated p53 protein containing 189 amino acid residues. Moreover, Western blotting demonstrated elevated HsRAD51 protein levels in GM1492 cells. The lack of sufficient levels of wild-type p53 and increased levels of HsRad51 protein may contribute to the elevated RecA-like activity in the GM1492 fibroblasts.
 ...
PMID:p53 splice acceptor site mutation and increased HsRAD51 protein expression in Bloom's syndrome GM1492 fibroblasts. 1076 46


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>