c-myc和p53蛋白在宫颈癌组织中的表达及临床意义

目的探讨c myc和p53蛋白在宫颈癌中表达的临床意义。方法采用免疫组化法检测51例正常宫颈、宫颈上皮内瘤样病变(CIN)和宫颈鳞癌中的c myc和p53蛋白的表达,并用TUNEL法检测细胞凋亡数。结果正常宫颈c myc和p53未见表达,宫颈鳞癌c myc和p53表达高于CIN(P<0.05)。宫颈鳞癌和CIN的TUNEL标记率均低于正常宫颈,宫颈鳞癌与CIN及正常组比较相差非常显著(P<0.01)。结论细胞凋亡可能与宫颈癌的形成过程有关,c myc和p53蛋白过度表达在宫颈癌的发生发展中起很重要的作用。     

Prognostic significance of p53 gene mutations and p53 protein expression in synovial sarcomas

Alterations to p53 seem to be of prognostic significance in soft tissue sarcomas, but their significance for synovial sarcomas has not been studied. We analysed 34 synovial sarcomas in 19 patients for p53 alterations (p53 gene mutations + p53 immunopositivity) and examined this factor for its prognostic value in a group of 15 primary tumours. DNA was prepared from paraffin-embedded tumour material by a modified proteinase K/phenol/chloroform extraction. p53 gene mutations of exons 5–8 were analysed by the PCR-SSCP-sequencing method. p53 protein expression was evaluated by immunohistochemistry using the murine monoclonal antibody DO1. We found two missense mutations (5.9%) and ten p53 immunopositive cases (29.4%). Both tumours with p53 mutations showed p53 protein expression. There was no significant correlation between p53 alteration and histological subtype, age, sex, or tumour size. The 5-year survival rate was 24.1%. Overall survival was significantly reduced in patients having synovial sarcomas with p53 alterations (P<0.001). In the multivariate Cox’s analysis, only p53 alterations (P=0.032) and tumour size (P=0.023) emerged as independent prognostic factors. We suggest that p53 alterations may be a useful prognostic indicator in synovial sarcomas, allowing rational clinical treatment and follow-up. Received: 13 April 1999 / Accepted:18 May 1999     

Absence of p53 gene mutations in hepatocarcinomas from a Mediterranean area of Spain

 The incidence of p53 gene abnormalities in human hepatocellular carcinoma (HCC) varies in different geographical areas, being higher in regions where hepatitis virus infection and dietary exposure to aflatoxin B1 are the most common aetiological agents. These mutations are less frequently encountered in Europe, although some studies have reported p53 protein overexpression in up to 45% of cases analysed. We have analysed 129 tumour samples of primary malignant hepatic neoplasms recovered from paraffin blocks processed in two pathology laboratories in a Mediterranean area of Spain (Valencia and Gerona). Among 14 cases in which p53 immunohistochemistry expression proved positive, 5 stained in more than 50% of the cell nuclei. By PCR-SSCP analysis we could detect the complete sequence from exon 5 through 8 in 70 cases and part of this region in the remaining cases, but no mutations were found. We found no relationship with the clinical stage, tumour stage or clinical outcome. We conclude that p53 gene alterations are not a major event in the malignant transformation of hepatic cells in this region of the Mediterranean. The variable incidence of p53 gene alterations in other geographical areas may reflect a different genetic background for the aetiology of HCC. Received: 14 September 1998 / Accepted: 28 January 1999     

IARC p53 mutation database: A relational database to compile and analyze p53 mutations in human tumors and cell lines

The tumor suppressor p53 gene is the most frequently mutated gene in human cancer. To date, more than 10,000 mutations have been described in the literature, and these data are available in various electronic formats on the World Wide Web. Here we describe the structure and format of the different p53 datasets maintained and curated at the International Agency for Research on Cancer (IARC) in Lyon, France. These include p53 somatic mutations (more than 10,000 entries), p53 germline mutations (144 entries), and p53 polymorphisms (13 entries), with the somatic mutations organized into a relational database using AccessTM. The main features of these datasets are (1) controlled entry with standardized format and restricted vocabulary, (2) inclusion of annotations on individual characteristics and exposures, and (3) a classification of pathologies based on the International Classification of Diseases for Oncology (ICD‐O). In addition, several interfaces have been developed to analyze the data in order to produce mutation spectra, codon analyses, or visualization of the mutation with the tertiary structure of the protein. All datasets and tools for analysis are available at http://www.iarc.fr/p53/homepage. Hum Mutat 14:1–8, 1999. © 1999 Wiley‐Liss, Inc.     

p53 Mutation and overexpression in hepatocellular carcinoma and dysplastic nodules in the liver

 In hepatocarcinogenesis, both de novo and multistep pathways have been suggested and in the latter a dysplastic nodule is the proposed precancerous lesion. In this study, we tried to ascertain whether or not the p53 gene is altered in low-grade/high-grade dysplastic nodules (LDN/HDN) and to determine the role of p53 alteration in multistep hepatocarcinogenesis. Eight hepatocellular carcinomas (HCCs), 9 HDNs, 17 LDNs and 25 cirrhotic nodules (LCs) were examined by polymerase chain reaction-single strand conformation polymorphism/direct sequencing and immunohistochemical staining for p53. Four of the 8 HCCs (50%) revealed p53 overexpression and 2 (25%) had missense mutations. Four of the 9 HDNs (44%) showed weak and/or focal p53 overexpression but none had mutation in the exons examined. Neither p53 overexpression nor mutation was found in 17 LDNs and 25 LCs. These results suggest that p53 mutation might be an unusual event in precancerous lesions of multistep hepatocarcinogenesis (DN-HCC sequence) and may play a less crucial part than in colorectal carcinogenesis. Received: 8 April 1997 / Accepted: 2 July 1997     

Genetic status of p53 in stomach cancer: Somatic mutations and polymorphism of codon 72

The incidence of somatic mutagenesis of p53 oncosuppressor protein in malignant tumors of the stomach and genetic polymorphism of p53 were studied in patients with stomach cancer on DNA samples isolated from tumor tissues obtained during surgery. The incidence of Pro/Pro genotype increased in the patients, while the percentage of Arg/Pro heterozygotes was markedly lower compared to long-living persons without cancer. The incidence of p53 somatic mutations in exons 5, 7, 8 was 70.8%; multiple mutations were detected in half of the examined patients. The relationship between the intensity of p53 mutagenesis and histological structure of the tumor was detected. The contribution of p53 genetic status to the risk of stomach cancer can be more effectively evaluated on DNA samples isolated from not only tumor cells, but also from normal tissues. The effects of epigenetic factors determining the intensity of somatic mutagenesis of p53 in tumors should be taken into account. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 2, pp. 205–209, February, 2006     

Absence of p53 gene mutation and infrequent overexpression of p53 protein in hepatoblastoma

Ten cases of hepatoblastoma were studies for overexpression of p53 protein by immunohistochemistry and for possible p53 gene mutation by single strand conformation polymorphism (SSCP) analysis and direct DNA sequencing of the polymerase chain reaction products. Only one case of the macrotrabecular type at stage IV showed overexpression of p53 protein. No DNA mobility shift was found in any of the cases studies by SSCP analysis. DNA sequencing performed on the case showing overexpression of p53 protein revealed no mutation within exons 5 to 8. The associated adrenal cortical carcinoma of the same case also showed overexpression of p53 protein, but no mutation of the p53 gene. These results indicate that mutation of the p53 gene is infrequent in hepatoblastoma. This observation supports the view that mutation of the p53 gene is not as important in the oncogenesis of childhood neoplasms as in adult cancers.     

Higher frequency of p53 gene mutations in diffuse large B-cell lymphoma with MALT component

p53 gene mutation is not a frequent event in the tumorigenesis of lymphomas and the expression of p53 protein is independent of p53 gene mutations. The present study aimed to investigate mutations in the p53 gene in a series of extranodal B-cell lymphomas, and its association with p53 protein expression. A total of 52 cases were graded histologically into Grade 1, Grade 2 and Grade 3 tumors and p53 protein expression was detected using immunohistochemistry. Mutations in the p53 gene were analyzed using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and mobility shifts were confirmed by direct sequencing. The tumors comprised 26 (50%) Grade 1, 9 (17%) Grade 2 and 15 (29%) Grade 3. A high proportion of Grade 2 (25%) tumors expressed p53 protein (P = 0.051) and carried p53 gene mutation (33%) (P = 0.218). However, p53 protein expression was not associated with p53 gene mutations (P = 0.057). Transversion mutations (88%) were more frequently detected than transition mutations (12%). The present study revealed that p53 gene mutations and p53 protein expression occurred in higher frequencies in Grade 2 tumors, which may be of pathogenetic importance. The high frequency of transversion mutations may reflect the influence of an etiological agent in the tumorigenesis of mucosa-associated lymphoid tissue (MALT lymphoma).     

p53 Alterations in thymic epithelial tumours

 The prognosis of thymic epithelial tumours depends on malignant behaviour that cannot always be predicted on histological grounds. This study aimed at identifying a molecular marker that would be useful in overcoming the drawbacks of histopathology. Forty-four thymic epithelial tumours were analysed for alterations of the tumour suppressor gene p53 using immunohistochemistry (antibodies D0-1 and CM-1) and PCR-based single-strand conformation polymorphism and DNA sequencing. Histological and clinical evaluation and also p53 analysis revealed three major tumour groups: non-organotypic thymic carcinomas with frequent p53 alterations (7/9) and occurrence of p53 gene mutations (2/9); malignant thymomas with frequent p53 alterations but without p53 gene mutations (11/18); and benign thymomas with rare p53 alterations and without p53 gene mutations (2/17). In non-organotypic thymic carcinomas p53 was detected with both antibodies. In contrast, thymomas lacked immunoreaction with D0-1 suggesting alteration of the antibody-binding site. Overall immunohistochemical results correlated with clinical stages (P < 0.01), pathohistology (P < 0.01), and survival times (P < 0.05). We consider immunohistochemical p53 detection to be a useful new prognostic factor for the evaluation of thymic epithelial tumours. Received: 5 September 1996 / Accepted: 17 February 1997     

Mutation of p53 with loss of heterozygosity in the osteosarcomatous component of a dedifferentiated chondrosarcoma

We investigated a dedifferentiated chondrosarcoma of a 61-year-old woman with an osteosarcomatous high-grade component for p53 alteration. The low-grade cartilaginous and the high-grade osteosarcomatous components of the tumor were macrodissected and evaluated separately by immunohistochemistry and molecular biology. We used PCR-SSCP analysis and direct sequencing to screen exons 4–8 for p53 mutations. The p53 intron 1-polymorphism was investigated for loss of heterozygosity. A functionally relevant p53 missense mutation in codon 193 of exon 6 (A-to-T transversion) with loss of wild-type allele was detected only in the dedifferentiated component. Using the monoclonal antibody DO-1, immunohistochemistry failed to show p53 overexpression. This evidence of p53 mutation may be regarded as at least a co-factor that ”switched” the preexisting low-grade conventional chondrosarcoma to a highly malignant dedifferentiated tumor. Received: 24 August 1999 / Accepted: 9 November 1999     

Molecular and immunohistochemical analysis of p53 mutations in scrapings and tissue from preinvasive and invasive breast cancer

 Mutations of the p53 gene appear to be one of the most common abnormalities in human cancer. Although many studies have been published about p53 alterations in breast cancer, data on molecular biological detection of p53 mutations in in situ lesions are still rare, and the implications for breast cancerogenesis are unclear. Tissue samples from 83 patients with different stages of breast cancer and from 13 patients with benign breast lesions were screened for p53 gene mutations by polymerase chain reaction (PCR) followed by temperature-gradient gel electrophoresis (TGGE). p53 protein accumulation was analysed by immunohistochemistry (IHC). Samples were gained from fresh-frozen tissue, scrapings, or paraffin embedded tissue. Additionally, 23 pairs of primary tumours and corresponding lymph nodes were examined. p53 gene aberrations were found in 55.7% of the infiltrating carcinomas, in 31.5% of the ductal carcinomas in situ (DCIS) and in one atypical ductal hyperplasia. A positive correlation was seen with high-grade tumours and with comedo. There was no statistically significant relationship with respect to age, menopausal status, tumour size, hormone receptor status or lymphatic invasion. Concordance between TGGE and IHC was seen in only 63% of the cases analysed. However, with regard to p53 mutation screening by TGGE, a high significance (P = 0.0008) was seen between standard tissue extraction and our scrape preparation technique. Among 8 pairs of primary tumours and their corresponding lymph node metastases, only 3 harbored identical p53 mutations in the same exon, while in 5 cases with mutant p53 in the primaries, no mutation was seen in the lymph node. Our data indicate that p53 mutations are frequent in breast tumours associated with unfavorable prognosis, including high-grade or the comedo histotype. There is evidence that p53 gene alterations occur early in breast cancerogenesis, as mutations were detected not only in in situ carcinomas but also in atypical ductal hyperplasia. Received: 14 April 1997 / Accepted 20 May 1997     

Pooled analysis of p53 mutations in hematological malignancies

A computerized database is described that contains information about 507 mutations in the p53 gene of hematologic tumors and corresponding cell lines. Analysis of these mutations indicated the following findings: First, mutational spectrum analysis in these tumors was found to be similar to the pattern found for other solid tumors. However, when the patterns of base substitutions were examined separately according to the types of hematologic malignancies, followed by subgroup analysis, notable differences (in some cases of statistical significance) emerged. Second, mutational pattern analysis indicates that about 48% of base substitutions in hematologic tumors are suspected to be associated with carcinogen exposure. Third, deletions and insertions are localized mainly to exons 5–8 and repeated DNA sequences. However, the unusual profile of variations in frequency within each type of tumor suggests that, in addition to endogenous damage to template DNA, there is the factor of exposure to environmental physical and chemical carcinogens/mutagens. Fourth, p53 protein alterations analysis indicate that most of the changes in the amino acids are “semiconservative,” presumably in order to avoid disrupting the structure of the p53 monomer. Consistent with this notion, structural mutations are more conservative than the binding mutations. Finally, molecular mechanisms that lead to p53 mutations, etiological factors that play a role in their formation, and the pathophysiological significance of consequent p53 protein alterations are discussed. Hum Mutat 12:4–18, 1998. © 1998 Wiley-Liss, Inc.     

p53 Protein expression in laryngeal squamous cell carcinomas bearing wild-type and mutated p53 gene

We performed an immunohistochemical analysis to investigate the expression of p53 protein in a panel of 18 laryngeal squamous cell carcinomas, 15 primary tumours and three in relapse, previously analysed by us for the presence of p53 gene mutations. Dysplastic and/or normal surrounding mucosa was evaluated in 15 different tumours. The results of our study are the following: (1) expression of p53 protein was observed in one out of five tumours positive for p53 gene mutations (20%) and in 10 out of 13 (80%) negative cases; (2), p53 protein over-expression was frequently observed in normal and/or dysplastic mucosa surrounding either wild-type (7/11) or mutated p53 tumours (2/4); (3), p53 immunoreactive cells showed a pattern of distribution in normal and mildly/moderately dysplastic mucosa (basal layers), different from that in severely dysplastic mucosa (whole thickness). These data further support the hypothesis that p53 protein over-expression may be a marker of the earliest phases of multistep tumorigenesis in laryngeal squamous cell carcinoma.     

脂肪组织源性肿瘤中c-myc和p53基因的异常表达

目的：探讨脂肪组织源性肿瘤与ｃ－ｍｙｃ和ｐ５３基因的关系。方法：采用ＬＳＡＢ免疫组化法,检测６２例脂肪组织源性肿瘤及瘤样病变ｃ－ｍｙｃ和ｐ５３蛋白表达。结果ｃ－ｍｙｃ在正常脂肪组织、脂肪组织良性病变中几乎不表达,主要在脂肪肉瘤中表达。ｐ５３只在脂肪肉瘤中表达。分化较高类型脂肪肉瘤ｃ－ｍｙｃ和ｐ５３表达阳性率明显低于分化较低类型脂肪肉瘤,脂肪肉瘤中,ｃ－ｍｙｃ和ｐ５３表达呈正相关。结论：实验结果提示     

Expression of E-cadherin and its relation to the p53 protein status in human breast carcinomas

 In breast carcinomas the TP53 gene is altered in 10–30% of cases. Alteration of the gene may lead to a general genomic instability, detected as deletions and/or amplifications at the gene level, and as altered expression at the mRNA and protein level. We have demonstrated a strong association between down-regulation of E-cadherin protein expression and alterations of the p53 protein, detected as TP53 gene mutation and/or protein accumulation in tumour samples from 210 patients with breast carcinomas (P <0.001). Investigation of allelic imbalance using microsatellite markers located near the E-cadherin locus was also performed. A higher frequency of loss of heterozygosity in the microsatellite marker closest to the E-cadherin locus was observed in samples with down-regulation of E-cadherin protein expression. A higher frequency of down-regulation of the E-cadherin protein expression was found in invasive lobular carcinomas than in invasive ductal carcinomas, although this difference was of borderline significant (P=0.084). Cases in the present series were also immunostained for c-erbB-2 protein overexpression. A significant association between p53 protein accumulation and cerbB-2 protein overexpression was seen (P=0.036). The results of the present study indicate that p53 protein may play a role in regulation of E-cadherin protein expression. Received: 29 May 1997)Accepted: 10 June 1997     

p53 mutations in human bladder cancer

Mutations in the tumor suppressor gene p53 play an important role in carcinogensis and tumor progression. To assess the status of p53 from genomic DNA from bladder cancer samples a two stage polymerase chain reaction was employed. The technique provided material for subsequent detection of mutations by Single Strand Conformation Polymorphism (SSCP) analysis followed by DNA sequence analysis. SSCP analysis of exons 5 to 9 of p53 was performed using fragments from PCR end-labeled with 32P followed by autoradiography using an electrophoresis system with temperature control. This SSCP method improved resolution of mutations in exons 5, 7, and 8 and the sharpness of bands in exons 6 and 9. Bands with altered migration patterns were excised from the dried SSCP gels, reamplified by PCR, and sequenced. Mutations in conserved exons 5, 6, 7, 8, and 9 of the p53 gene were analyzed from bladder tumor biopsies. Our results are consistent with the literature in that mutations in p53 are predominantly found in high grade bladder cancer (Odds Ratio = 4.05, Fisher Exact P = 0.104); however, the results were not statistically significant due to small numbers. Eight of 35 (23%) tumor samples examined showed mutations in p53 (including two double mutations). Six of 13 (46%) grade III and IV tumors had p53 mutations vs. 2 of 17 (12%) grade I and II tumors. Normal individuals carried no p53 mutations. We found no correlation between pack years of smoking and mutation in p53. The spectrum of mutations confirmed a high proportion of G:C C:G transversions as well as the occurrence of double mutations. © 1994 Wiley-Liss, Inc.     

乳腺癌中p53基因丢失与p53 mRNA高表达相关性研究

为探讨乳腺癌组织中ｐ５３基因丢失与ｐ５３ ｍＲＮＡ表达的相关性，应用Ｓｏｕｔｈｅｒｎ杂交及反转录－定量ＰＣＲ技术对４７例乳腺癌组织进行了检测。结果发现：ｐ５３基因杂合性缺失率为３４．０％；在乳腺正常腺体中有中度ｐ５３ＲＮＡ表达，面 肿瘤组织中有４０．０％，患者伴ｐ５３ ｍＲＮＡ高表达。ｐ５３基因与ｐ５３ ｍＲＮＡ高表达之间呈显著性相关。     

Germline p53 mutation at codon 133 in a cancer-prone family

 We identified four families in which we suspected the presence of genetic factors predisposing them to cancer. We examined one family with features suggesting Li-Fraumeni syndrome for the presence of a germline p53 mutation in 13 of its members. To detect germline p53 mutations we performed polymerase chain reaction/nonradioisotopic single-strand conformation polymorphism and DNA sequencing analysis on exons 4–9 of the p53 gene. Mutated polymerase chain reaction–restriction fragment length polymorphism analysis was also performed on exon 5 to confirm the mutation identified by the sequencing analysis. A novel germline p53 mutation was identified at codon 133 (ATG→AGG) in exon 5, resulting in the substitution of arginine for methionine, in all four cancer-affected individuals and in three apparently healthy individuals. We also analyzed tumor specimens for additional p53 mutations in the wild-type alleles using the same methods. However, heterozygosity was retained, and no other additional mutations in the wild-type allele were identified in any of the tumor tissues. It is possible that additional mutations in the wild-type allele are not always necessary for the loss of tumor suppressor functions. This study presents serious clinical and ethical problems about the predictive value of identifying germline p53 mutations in presymptomatic carriers. However, accurate predictive testing will be very useful in identifying unaffected individuals who are at increased risk of developing cancer and in detecting cancer at an early stage. Received: 24 July 1996 / Accepted: 29 October 1996     

p21 Expression in colorectal carcinomas: a study on 103 cases with analysis of p53 gene mutation/expression and clinic-pathological correlations

The WAF1/CIP1 gene product, p21, an inhibitor of cyclin-dependent kinases, is a critical downstream effector in the p53 pathway. The expression of p21 in human neoplasms is heterogeneous, and may be related to p53 functional status. We evaluated p21 immunoreactivity in 103 colorectal carcinomas (CC) in relation to the p53 gene and protein alterations and clinico-pathologic parameters. High p21 expression (more than 10% reactive cells) was seen in 39% of cases. p21 staining was heterogeneous and often detected in clusters of tumour cells; in some tumours p21 staining was more pronounced in superficial areas. No relation was seen between p21 immunoreactivity and site of the tumours (right vs left), TNM stage and grade. p21 expression was related to p53 status as evaluated with IHC or with SSCP analyses, low p21 expression usually being associated with p53 protein overexpression (P=0.048) and p53 gene alteration (P=0.005). The strongest associations were seen when the combined p53/p21 immunophenotype was compared with p53 gene alterations (P=0.0002). These data support the hypothesis that p21 expression in CC is mainly related to p53 functional status, suggesting that p21 expression could be an interesting adjunct in the evaluation of the functional status of the p53 pathway in CC. Received: 22 February 1999 / Accepted: 21 June 1999     

Apoptosis and proliferative activity of non-Hodgkin's lymphomas: Comparison with expression of bcl-2, p53 and c-myc proteins

In order to clarify the role of spontaneous apoptosis of non-Hodgkin's lymphomas In the growth regulation system, apoptdc Indices (Al) assessed by DNA nick end-labeling and proliferative activity, estimated In terms of Ki-67 Iabeling Indices (KI) and mitotic Indices (MI), were compared. in addition, expresslon of bcl-2, p53 and c-myc was also examIned in relation to these Indicators. For thls study, 103 Iymphoma cases were used, comprising 72 of B cell and 31 of T cell origin (42 nodal and 62 extranodal). Al, KI and MI were signiffcantty Increased in llne with bcl-2 negativity and p53 positivify, and there was no relation to the T, B cell classification or expression of c-myc. These Indicators positivety correlated overall. Posltive correlation was stricter in groups belleved to represant a good pragnostic predictive factor, such as B cell origin, bci-2(+), p53(-) and c-myc(-). Significant cross-correlation was noted only between bcl-2 wersus T, B cell classification. However, no inverse correlation between bcl-2 and p53 was evident. These results sug gest, in non-Hodgkin's lymphomas, that apoptosls plays an Important role together with proliferative activity in counterbalancing tumor volume, and is strlctty linked to bcl-2 expression, less 80 to p53 expresaion, but Independent of T, B cell classification and c-myc expression. Apoptotlc indices may be a perdlctive Indicator for prognosis simllar to proliferative activity.