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

Mutations of suppressor gene p53 was studied in 36 cases of silica related lung cancer and 6 cases of welding fume related lung cancer with immunohistochemical and PCR-SSCP methods. Cancer tissues were embedded in paraffin and stored for 13.4 years in average. Results revealed that there was abnormal mobility shift of electrophoresis in 18 cases with 20 point mutations of 42 specimens tested, accounted for 42.9%, and 50% (10/20) of the mutations were clustered in exon 8. This finding differed from mutational spectrum of gene in non-occupational lung cancer, in which mutation frequency of exon 8 ranged from 17.5% to 23.5%. Gene mutation frequency in varied pathological categories of pneumoconiosis related lung cancer also differed from that in common lung cancer. In the latter, the highest one was in small cell lung cancer (70%) and the lowest in adenocarcinoma (33%), but in the former, the highest in adenocarcinoma (53.9%) and the lowest in small cell lung cancer (30.8%). Immunohistochemical observations also showed a very high prevalence of p53 gene mutation expression (46.9%). Sequencing, which was determined in two cases of this study, revealed that two point mutations all occurred in non-hotspot codon 144 of p53 gene. Difference in gene mutation spectrum suggests that there exist specific carcinogens and carcinogenesis in silica and welding fume related lung cancer.
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PMID:[A preliminary study on p53 gene in lung cancer tissues of workers exposed to silica and welding fumes]. 981 93

There are few reports on the p53 status of small cell lung cancer (SCLC) and advanced non-SCLC (NSCLC) because surgically resected specimens are generally not available. Therefore, we evaluated p53 immunostaining in 175 transbronchial biopsy (TBB) specimens obtained from patients with all stages of lung cancer and retrospectively evaluated the relationship between p53 status and clinical parameters. All of the specimens were obtained prior to therapy. Formalin-fixed, paraffin-embedded TBB specimens were immunostained using an anti-p53 antibody (DO-1). p53 protein was detected in 55% (61 of 111) of NSCLCs and 58% (37 of 64) of SCLCs. The rate of positivity increased significantly with increasing stage (stages I and II, 45%; stage III, 54%; stage IV, 66%), but not with other clinical parameters. Ninety-five patients were evaluated for their response to chemotherapy. Positive staining for p53 correlated significantly with unresponsiveness to chemotherapy in NSCLC (response rate of 13 versus 60%; P = 0.006), but not in SCLC (80 versus 57%; P = 0.22). p53 positivity was a statistically significant negative prognostic factor for stage III and stage IV NSCLC (P = 0.02), but not for stage I and stage II NSCLC (P = 0.79). There was no survival difference relative to p53 status in SCLC (P = 0.35). These results indicate that p53 overexpression in TBB specimens predicts poor prognosis and chemoresistance in advanced stage NSCLC.
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PMID:The utility of p53 immunostaining of transbronchial biopsy specimens of lung cancer: p53 overexpression predicts poor prognosis and chemoresistance in advanced non-small cell lung cancer. 981 99

We performed genetic analysis on 12 second primary non-small cell lung cancers in patients surviving small cell lung cancer to assess the potential contribution of smoking to the development of these tumors. Mutations of TP53 were found in three (25%) tumors, KRAS2 in three (25%) tumors, and CDKN2 in two (18%) tumors. Four (50%) mutations (one each in TP53 and CDKN2 and two in KRAS2) were G:C to T:A transversions on the coding strand, a mutation accounting for approximately one-third of mutations in smoking-related tumors but uncommonly found in lung cancers not associated with smoking. The genetic changes in these second lung cancers are more representative of smoking-associated malignancies than lung cancers arising in patients occupationally exposed to irradiation and atomic bomb survivors.
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PMID:Genetic analysis of second primary lung cancers in patients surviving small cell lung cancer. 981 74

While resistance to chemotherapy is a major problem in lung cancer treatment, there is no useful predictor of treatment response. We thus designed this study to determine the utility of p53 and P-glycoprotein expression in predicting the response to chemotherapy in patients with primary lung cancer, retrospectively. We evaluated transbronchial biopsy (TBB) specimens from 60 patients with lung cancer, who were previously untreated. Formalin-fixed, paraffin-embedded TBB specimens were immunostained using anti-p53 antibody (DO-1) and anti-P-glycoprotein antibody (JSB-1). The positivity of p53 was 63%, and that of P-glycoprotein was 17%. No correlation was observed between p53 and P-glycoprotein immunostaining. Positivity of p53 correlated significantly (P = 0.004) with a lack of response to chemotherapy in non-small cell lung cancer (NSCLC), but not in small cell lung cancer (SCLC). In contrast, positivity of P-glycoprotein was correlated with chemotherapy resistance in SCLC (P = 0.003), but not in NSCLC. Multiple logistic regression analysis revealed that positive immunostaining for p53 was a significant risk factor for chemotherapy resistance in NSCLC. These results suggest that immunostaining of p53 and P-glycoprotein for TBB specimens may help to predict response to chemotherapy in NSCLC and SCLC, although the results should be confirmed in a larger, more homogeneous series.
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PMID:Immunohistochemically detected p53 and P-glycoprotein predict the response to chemotherapy in lung cancer. 984 16

Prognostic value of p53 gene mutation was determined in 95 radically operated non small cell lung cancer patients (78 males and 17 females, mean age 57.8 years). Study group included 62 cases of squamous cell carcinoma, 30--adenocarcinoma and 3--large cell carcinoma. There were 52 patients in stage I disease, 16--in stage II, 26--in stage IIIa and one--in stage IIIb. Paraffin-embedded samples of resected tumors were assayed for p53 mutations with the use of PCR/SSCP analysis. p53 mutation were present in 22 cases (23%). The median survival in patients with and without p53 mutations were 49 and 75 months (p = 0.46), respectively, and the five-year survival rate 53% and 50%, respectively. In stage I disease the median survival for patients with p53 mutation was 53 months and for those without mutations the median survival could not be determined as more then a half of them were alive. Median survival in stage II patients with and without mutations was 35 months and 44 months (p = 0.62), and in stage IIIA--9.5 months and 17 months, respectively (p = 0.37). The results of this study indicate that p53 gene mutation is not correlated with prognosis in non-small cell lung cancer patients.
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PMID:[Evaluation of the prognostic significance of P53 mutation in patients with non-small cell lung cancer]. 985 49

The accumulation of mutant p53 protein in cancer cells was observed by immunohistochemistry analysis. DNA was extracted from paraffin-embedded tissue. Exons 5, 7 and 8 were amplified and studied by PCR-SSCP and sequencing analysis. Ten cases of asbestos associated cancer tissue were studied, of which five cases had adenocarcinoma, and the other five had mesothelioma, squamous carcinoma, small cell lung cancer, adenosquamous carcinoma and malignant lymphoma respectively. Employing monoclonal antibody PAb1801, five cases were found to be mutant p53 protein positive. Seven cases were found to have mutations by PCR-SSCP. A total of 7 cases (8 mutations) were found to be positive and 4 cases were found to be positive by both of these analyses. Of the 8 mutations found by SSCP analysis, 4(50%, 4/8) were clustered in exon 8. A high mutation frequency was noticed in adenocarcinoma (80%, 4/5). Sequencing analysis on two specimens revealed two hotspot mutations. In codon 234, TAC for tyrosin was mutated to AAC for asparagine by a T to A transversion of the first letter. In codon 273, CGT for arginine was mutated to AGT for serine by a C to A transversion of the first letter. In conclusion, the mutation of p53 gene is common in asbestos associated cancers. However, the mutational spectrum of asbestos associated cancers might be different from that of non-asbestos associated cancers.
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PMID:p53 gene mutations in asbestos associated cancers. 986 81

It has been suggested that a deregulated cell cycle control contributes to the development of human malignancies due to the loss of critical antiproliferative mechanisms. The cell cycle is controlled at two checkpoints, one at the G1-S and another at the G2-M transition. Several genes including the structurally related p21WAF/CIP1 gene, the downstream mediator of the p53 tumor suppressor gene, and the p27Kip1 gene have been identified as inducers of cell cycle arrest at the G1 checkpoint when substantial DNA damage has occurred to avoid further replication of the altered genome. Recently, a heat stable 27 kDa protein, the transcript of the p27Kip1 gene, has been identified and was suggested to substantially participate in cell cycle control at the G1 checkpoint. Previous investigations have correlated decreased expression of the p27Kip1 protein with an increased biological aggressiveness of breast and small cell lung cancer. However, the molecular-genetic analysis of a variety of human malignancies including prostate cancer failed to identify any alteration at the p27Kip1 gene locus, therefore suggesting a loss of p27Kip1 protein expression to result from post-transcriptional/post-translational events or from so far unknown regulatory mechanisms. So far, bladder cancer specimens have neither been investigated for p27Kip1 alterations on the DNA level, nor has the result of molecular genetic analysis been correlated with an immunohistochemically detected expression of the gene product, the p27Kip1 protein. The present study is the first to describe p27Kip1 gene alterations on the DNA level in 3 of 42 muscle invasive bladder cancer specimens. In contrast, loss of p27Kip1 protein expression was observed in 14 of 42 (33%) tumors. According to the previously reported observation in a variety of human malignancies, in bladder cancer loss of p27Kip1 protein expression seems to result from post-transcriptional or post-translational events.
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PMID:Analysis of the cyclin-dependent kinase inhibitor p27Kip1 in muscle invasive bladder cancer. 986 34

Spontaneous apoptosis was assessed in ten small-cell (SCLC) and five non-small cell (NSCLC) lung carcinoma cell lines by the TUNEL assay and chromatin cleavage. TUNEL staining showed significantly higher apoptotic index (AI) in SCLC (2-20%) compared with NSCLC lines (0.2-1%) in untreated exponentially growing cells. Six out of ten SCLC and none of the NSCLC showed DNA fragmentation when analysed by agarose gel electrophoresis. Field inversion pulse gel electrophoresis was used in a subset of cell lines and showed the presence of high molecular weight fragments in untreated SCLC lines U-1285 and U-1906 cells, but not in the NSCLC line U-1810. Important molecular determinants of apoptosis were studied by Western blot. Bcl-2 was detected at highest level in SCLC. There was no correlation between the ratio Bcl-2/Bax and AI in all tested cell lines. Neither p53 nor c-Myc protein status correlated to AI. Pro-caspase-3 was expressed in all cell lines without correlation to AI and no difference between the SCLC and NSCLC groups was found. In conclusion, this study shows a high degree of spontaneous apoptosis in SCLC lines compared to NSCLC lines unrelated to Bcl-2/Bax ratio.
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PMID:Higher spontaneous apoptotic index in small cell compared with non-small cell lung carcinoma cell lines; lack of correlation with Bcl-2/Bax. 986 2

Using different molecular techniques, DNA has been shown to be present in plasma of patients with several types of tumors. Mutations of TP53 are the most common genetic changes in human cancers. We investigated the presence of TP53 gene mutations in plasma DNA of breast and small cell lung cancer patients. Tumor and plasma DNA of 25 patients were studied by PCR-SSCP and direct sequencing, through exons 5, 6, 7, and 8, of TP53. Six cases of mutations in tumor DNA were observed that, in 3 cases (50%), were also identified in plasma of the same patients. Mutations of the TP53 gene are seen in plasma DNA of cancer patients, and may prove to be a useful new tool in the management of these patients.
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PMID:TP53 gene mutations in plasma DNA of cancer patients. 988 84

Small cell lung cancer (SCLC) is common in men and women, has a very poor prognosis, and is therefore a major cause of premature mortality. As such, any prospects for improved therapy are of great significance. The promise of telomerase as a therapeutic target is now close to realization with extremely encouraging preclinical studies aimed at the RNA component (hTR) of telomerase. The rational integration of telomerase therapeutics into clinical trials will therefore require tumours to be well characterized for hTR expression. Despite the large number of cancer types now characterized for telomerase or telomerase component gene expression, only a handful of SCLC samples have been analysed. Given the major clinical problem with treating SCLC, we specifically set out to address the issue of hTR expression in neuroendocrine tumours. Our study covers 91 pulmonary neuroendocrine tumours (62 SCLC and 29 carcinoid tumours). We present data to show that upregulation of the RNA component of telomerase occurs in 98% of human SCLCs. Interestingly, the less aggressive carcinoid tumours of the lung had a significantly lower frequency of hTR expression (P < 0.01). Importantly, we compare hTR expression in this series to the well characterized biological targets p53 and BCL2, and show hTR to be expressed more frequently. Therapies directed at the RNA component of human telomerase are in active development and these data show SCLC to be a prime target for such therapies.
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PMID:Is small cell lung cancer the perfect target for anti-telomerase treatment? 1042 23


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