p53 protein accumulation and p53 gene mutation in colorectal cancer

Comparison of immunohistochemical methods for detection of protein p53 accumulation and molecular techniques for analysis p53 gene mutation in colorectal cancer is presented. Thirty eight patients were included: all underwent surgery without preoperative treatment. Sex of patients, tumor localisation, macro and microscopic type of cancer and staging according to Astler-Coller and Jass classifications were evaluated. Protein p53 accumulation was detected by the streptavidin-biotin method using DO-7 (Dako) antibody. The number of cells stained were classified semiquanititatively according to a scoring system: (-)no positive cells, (+) : 10-30% positive cells, (++) : 40-70% positive cells, (+++) : >70% positive cells. For all cancer samples, exons 5 to 9 of p53 gene were amplified from isolated genomic DNA. PCR products were subjected to single standed conformational polymorphism analysis. All product were also directly sequenced on ABI PRISM 377 apparatus using fluorescent dideoxyterminators chemistry. The protein p53 accumulation was detected in 53% (20/38), whereas p53 gene mutation was seen in 55% (21/38). Among them, 15 patients (39%) with overexpression showed mutation in exon 5-8 gene p53. Discrepancies between results were noted in 29%. In conclusion, the necessity of both methods immunohistochemical and molecular is indicated for the objective evaluation of functional and structural status of p53 gene and protein.     

Alterations of the p53 gene in human primary cervical carcinoma with and without human papillomavirus infection.

A previous report using cervical carcinoma cell lines suggests that the inactivation of two tumor suppressor gene products, p53 and pRB, either by complex formation with the E6 and E7 proteins of oncogenic human papillomaviruses (HPVs) or by mutation, may be an important step in cervical carcinogenesis (M. Scheffner et al., Proc. Natl. Acad. Sci. USA, 88: 5523-5527, 1991). The present study was designed to clarify the association between p53 inactivation and infection with oncogenic HPVs in primary carcinomas of human uterine cervix. We examined 36 primary cervical carcinomas for the presence of HPV DNAs by Southern blot analysis with probes specific for HPV-16, -18, -31, -33, -52, -56, and -58. HPV DNA sequences were detected in 19 of 36 tumors: 10 cases with HPV-16; 3 cases with -18; 3 cases with -58; 2 cases with -56; and one case with -52. The presence of HPV-16 and -18 in cervical carcinomas was further reexamined using polymerase chain reaction. HPV DNA sequences were detected in an additional 10 cases: 9 cases with -16 and one case with -18. The inactivation of the p53 gene by allelic loss or by point mutation was also examined. No allelic loss at the polymorphic site in codon 72 of the p53 gene was detected in any of 10 informative cases. Missense point mutations in the highly conserved regions of the p53 gene were demonstrable as single-stranded conformational polymorphisms of polymerase chain reaction-amplified DNA fragments and subsequently identified by direct DNA sequencing. Point mutations were detected in only two cases: one with an ATG----CTG transversion in codon 133 of exon 5, resulting in a Met----Leu substitution, and another with a CGG----TGG transition in codon 248 of exon 7, resulting in an Arg----Trp substitution. Both tumors with point mutations in p53 genes were among 10 tumors which contained a small copy number of HPV-16 DNA sequences (1 copy of HPV/10(1) to 10(5) cells) detectable by polymerase chain reaction amplification but not by Southern blot analysis of genomic DNAs derived from the tumors. None of 19 tumors with a large copy number of HPV DNA sequences detectable by Southern blot analysis (more than 1 copy of HPV/2 to 10 cells) nor any of 7 tumors with undetectable HPV DNA sequences contained p53 gene mutations in the regions examined.(ABSTRACT TRUNCATED AT 400 WORDS)     

p53 protein accumulation and p53 gene alterations (RFLP, VNTR and p53 gene mutations) in non-invasive versus invasive human transitional bladder cancer

Eleven non-invasive and 24 invasive transitional cell bladder cancers were analysed for molecular alterations to the p53 gene and nuclear accumulation of the p53 protein. 9% (1/11) of non-invasive rumours and 21% (5/24) of invasive tumours revealed nuclear accumulation in more than 50% of the tumour cells. PCR analysis of D17S30 showed loss of heterozygosity (LOH) in invasive tumours (3/24; 12%). Two invasive tumours harboured point mutations in exon 6 and exon 7, respectively (8%). Our results indicate that p53 protein overexpression correlates with tumour progression, p53 gene mutations and LOH detected by PCR.     

软组织肉瘤中p53基因的突变和蛋白的表达研究

目的检测软组织肉瘤中p53基因的突变和蛋白的表达情况。方法应用PCR-SSCP和DNA测序的方法检测p53基因的突变,免疫组织化学技术Envision二步法检测p53蛋白的表达。结果 63例软组织肉瘤中检测到p53基因突变18例（28.6%）,突变位点主要在第6外显子和第7外显子,突变和组织学分级间无明显相关性;63例p53蛋白的表达44例,蛋白的表达与组织学分级间无明显相关性;且p53基因的突变与p53蛋白的表达无明显相关性。结论 p53基因的突变和p53蛋白的表达可能作为软组织肉瘤发生的一个重要因素。     

人乳腺癌组织p53基因突变及过度表达的临床意义

应用聚合酶链反应－单链构象多态（ＰＣＲ－ＳＳＣＰ）分析和流式细胞术（ＦＣＭ），研究３０例患者乳膛癌组织Ｐ５３基因５￣８外显子的突变情况、Ｐ５３蛋白免疫组化检出情况、ＤＮＡ倍体及雌激素受体（ＥＲ）含量；并与各生物学参数进行了相关研究，以探讨Ｐ５３基因与乳腺癌发生、发展的关系。结果提示：１．全组１４例（４６．７％）发现Ｐ５３基因突变，其中１例为原位导管癌。２．Ｐ５３蛋白检出阳性率为５３．３％（１６／３     

p53、人半翼基因在宫颈癌前病变及宫颈癌中的表达及相关性分析

目的 探讨p53、人半翼基因(hWAPL)在宫颈癌前病变及宫颈癌中的表达及相关性.方法 选取67例低级别宫颈上皮内瘤变(CIN)患者(CINⅠ)、58例高级别CIN患者(CINⅡ～Ⅲ)、42例宫颈癌患者和39例宫颈炎患者,取相应的CIN组织、宫颈癌组织和正常宫颈组织,免疫组化法检测HPV16/18型E6、p53、hWAPL蛋白的表达情况.根据人乳头瘤病毒(HPV)感染情况,206例患者中合并HPV感染117例,未合并HPV感染89例,比较合并与未合并HPV感染宫颈癌患者p53、hWAPL蛋白表达情况,探讨HPV感染与p53、hWAPL蛋白阳性表达的相关性.结果 HPV16/18型E6、p53、hWAPL蛋白在正常宫颈组织、CINⅠ组织、CINⅡ～Ⅲ组织和宫颈癌组织中阳性表达率和阳性表达强度逐渐升高,正常宫颈组织﹤CINⅠ组织﹤CINⅡ～Ⅲ组织﹤宫颈癌组织(P﹤0.01).合并HPV感染患者p53、hWAPL蛋白的阳性表达率均明显高于未合并HPV感染患者(P﹤0.05).Spearmen相关性分析结果显示,宫颈组织中HPV16/18型E6蛋白的阳性表达与p53、hWAPL蛋白的阳性表达均呈正相关(r=0.635、0.701,P﹤0.01),宫颈组织中p53蛋白的阳性表达与hWAPL蛋白的阳性表达呈正相关(r=0.763,P=0.000).结论 合并HPV感染的宫颈癌患者宫颈癌组织中p53?hWAPL的阳性表达率和表达强度均较高,HPV16/18型E6蛋白的阳性表达与p53?hWAPL蛋白的阳性表达均呈正相关.     

Tetraploid arrest with overexpressed non-mutated p53 in germ cell cancers

Immunocytochemical study of 40 germ cell cancers, 31 bladder cancers and 27 squamous head and neck cancers using monoclonal antibodies (Mab) specific for p53, Bcl-2 and HSP70 was carried out. The results showed that 89% of germ cell cancer compared to 7% of bladder and 2% of squamous head and neck cancers were positive for p53 using Mab 240. In contrast only 60% of germ cell cancers (20% strong) but 100% of bladder (80% strong) and head and neck (75% strong) were positive for Bcl-2. There was a higher p53 positivity for the more chemoradiosensitive seminoma (82%, n=17) compared to non-seminoma (33%, n=6) and the inverse for Bcl-2 (53% vs. 83%). Taken together with emerging data that the putative stem cell for all germ cell cancers, the tetraploid pachytene primary spermatocyte normally expresses p53, these results support the view that near tetraploid overexpression of functional p53 in germ cell cancer may be a factor in why germ cell cancers are more chemosensitive than the common adult cancers. They also highlight the need for better understanding of the cell cycle check points during meiosis as possible molecular targets that would increase the chemosensitivity of non-germ cell cancers.     

Mutations in the TP53 gene and protein expression of p53, MDM 2 and p21/WAF-1 in primary cervical carcinomas with no or low human papillomavirus load.

Several studies have focused on the role of p53 inactivation in cervical cancer, either by inactivating mutations in the TP53 gene or by degradation of the p53 protein by human papillomavirus (HPV). In this study, primary cervical carcinomas from 365 patients were analysed for presence of HPV using both consensus primer-sets and type-specific primer-sets. Nineteen samples were determined to have no or low virus load, and were selected for further analyses: mutation screening of the TP53 gene using constant denaturant gel electrophoresis (CDGE) followed by sequencing, and protein expression of p53, MDM2 and p21 using immunohistochemistry (IHC). Mutations in the TP53 gene were found in eight samples (42%). Elevated p53 protein expression was significantly associated with presence of a mutation (P < 0.007). P21 protein expression was detected in 16 of the 19 carcinomas. No p21 expression was seen in normal cervical tissue. Two samples, both with wild-type p53, had elevated MDM2 expression. Compared with a previous study from our group, of mainly HPV-positive cervical carcinomas, in which only one sample was found to contain a TP53 mutation, a significantly higher mutation frequency (P < 0.001) was found among the carcinomas with no or low virus load. Although p53 inactivation pathways are not detected in every tumour, our study supports the hypothesis that p53 inactivation, either by binding to cellular or viral proteins or by mutation, is essential in the development of cervical carcinomas.     

The p53 tumor-suppressor gene is overexpressed but not mutated in human atherosclerotic tissue

Excessive proliferation of smooth muscle cells (SMC) in the arterial intima is thought to be a major contributing factor to the development of atherosclerosis. One of the theories put forward to explain the aberrant growth is that genetic alterations similar to those observed in cancers also occur in the SMC. Since mutations in the p53 tumour suppressor gene and the c-Ki-ras oncogene are the most common genetic alterations observed in a wide variety of tumour types, we searched for evidence of mutation in human atherosclerotic tissue. DNA was extracted from atherosclerotic plaques and screened for p53 and c-Ki-ras gene mutations using polymerase chain reaction-single strand conformation polymorphism analysis. Tissue sections were also examined for overexpression of p53 protein using an immunohistochemical technique. The molecular analysis showed that wild-type p53 and c-Ki-ms gene sequences were present in all 54 specimens examined. Overexpression of p53 protein was found in 61% of samples. Our results do not support the view that genetic alterations similar to those occurring in cancer contribute to the abnormal proliferation of SMC, although we caution that only two cancer-related genes were studied. Epigenetic changes to the gene products could play a role however, as evidenced by overexpression of p53 protein in many of the atherosclerotic specimens.     

Association among p53 gene mutation,nuclear accumulation of the p53 protein and aggressive phenotypes in breast cancer

In order to reveal whether differences in the type and site of p53 gene mutations influence the function of the gene and tumor phenotype, we examined nuclear accumulation of the p53 protein immunohistochemically, loss of the other p53 allele by restriction-fragment-length polymorphism analysis, and histological grade of atypia in 52 breast-cancer tissue specimens in which the position and pattern of the mutation were identified. When mis-sense point mutations ordeletionsof3nbases(n = 1, 2,…), which did not cause a frame shift downstream, occurred within codons 110-180 or 234-285, containing highly conserved regions, the p53 protein was almost always (92%) accumulated in nuclei in a majority of the cancer cells. When these mutations occurred outside these regions, only 46% of the cases showed nuclear accumulation of the protein in a majority of cancer cells. In tumors with non-sense point mutations or deletion of 3n+1 or 3n + 2 bases (n = 0, 1, 2,…), which caused a downstream frameshift, nuclear accumulation of the p53 protein was absent in 93% of cases. Irrespective of the mutation site or pattern, a majority of cases showing p53 mutation revealed loss of hetero-zygosity on 17p13 (83%), which suggested they do not carry wild-type p53 allele, and the highest histological grade of atypia (90%). Regardless of differences in their protein-expression pattern, a majority of the p53 gene mutations were suggested to function in a recessive mode and to be involved in the development of histologically aggressive breast cancer. © 1994 Wiley-Liss, Inc.     

p73 protein expression correlates with radiation-induced apoptosis in the lack of p53 response to radiation therapy for cervical cancer

PURPOSE: p73 belongs to the p53 tumor suppressor family of genes and can inhibit cell growth in a p53-like manner by inducing apoptosis or cell cycle arrest. Here, we investigated whether p73 could compensate for impaired p53 function in apoptosis induced by radiation therapy (RT) for cervical cancer. METHODS AND MATERIALS: Sixty-eight patients with squamous cell carcinoma of the cervix who received definitive RT combined with (n=37) or without (n=31) cisplatin were investigated. Biopsy specimens were excised from the cervical tumor before RT and after 9 Gy. RESULTS: Mean apoptosis index (AI) was 0.93% before RT and 1.97% after 9 Gy with a significant increase (p<0.001). For all patients, there was a significant correlation between p73 expression positivity after 9 Gy and AI ratio (AI after 9 Gy/AI before RT) (p=0.021). Forty-one patients were regarded as the p53-responding group according to the expression of p53 after 9 Gy, whereas the remaining 27 patients were regarded as the p53-nonresponding group. A significant correlation between p73 expression after 9 Gy and AI ratio was observed in the p53-non-responding group (p<0.001) but not in the p53-responding group (p=0.940). CONCLUSION: Our results suggest that p73 plays an important role in compensating for the lack of p53 function in radiation-induced apoptosis of cervical cancer.     

Expression of the p53 and Maspin protein in primary prostate cancer: correlation with clinical features

The serine protease inhibitor Maspin has been reported to inhibit the invasiveness and motility of prostate cancer tumor cells. Additionally, a p53-dependent regulatory pathway of Maspin in prostate cancer cell lines has been indicated. The first aim of our study was to determine the prognostic value of Maspin protein expression for the recurrence-free survival of patients undergoing radical prostatectomy for the treatment of clinically localized prostate cancer. Secondly, Maspin expression was correlated to p53 protein expression in order to gain additional information on a possible and previously suggested regulatory influence of the wild-type p53 protein on the Maspin protein expression. Tumor specimens obtained from 84 patients undergoing radical prostatectomy for localized prostate cancer were investigated for the expression of the Maspin and p53 protein by an immunohistochemic approach. Maspin protein expression was correlated with further patients' and tumor characteristics such as tumor stage, histologic grading, regional lymph node status, p53 protein expression and recurrence-free survival of the patients following radical prostatectomy. After a median follow-up of 64 months (24-197 months), 23 of 40 patients (58%) with a negative or decreased Maspin expression (group 1) developed local recurrence or systemic tumor progression in contrast to 8 of 44 patients (18%) with a retained expression of the Maspin protein (group 2) (p = 0.02; log-rank test). The median recurrence-free survival following radical prostatectomy was 26 months (12-37 months) for group 1 patients and 41 months (5-134 months) for patients from group 2 (p = 0.04). A positive immunohistochemic staining reaction for the p53 protein was significantly correlated with a decreased expression of the Maspin protein (p = 0.015; Spearman correlation coefficient). Additionally, loss of Maspin protein expression was correlated to higher tumor stages (p = 0.002) and an increasing histologic dedifferentiation (p = 0.03). This is the first study to indicate that Maspin protein possibly functions as a clinically relevant inhibitor of tumor progression, preventing the local invasiveness and further systemic progression of prostate cancer. Our investigation delivers first hints for a p53-dependent regulatory pathway of the Maspin protein in human prostate cancer.     

p53 Mutations and protein overexpression in primary colorectal cancer and its liver metastasis

Although there have already been many studiesreported about p53 statIJs on primary colorectal cancerand / or hepatic metastases,t'. 2] we have not found anyrepoft that compares p53 status between primary andmetastatic lesions in each patient on an individual level.34 patieflts with colorectal cancer and liver metastaseswere chosen for this study. P53 status in Primary and livermetastatic tllmor lesions of every individual wereinvestigated, in order to understand that p53 gene statusduring tumo…     

大肠癌原发灶和肝转移灶p53变异及蛋白表达

目的 了解Ｐ５３及其蛋白在大肠癌发生、转移过程中的动态变化。方法Ｐ５３基因外显子５－９以ＤＧＧＥ及自动ＤＮＡ序列分析来检测,Ｐ５３蛋白表达以免疫组化方法检测。结果 ３４例中２１例呈Ｐ５３变异,占６１．８％,其中５例仅在肝转移灶发现Ｐ５３变异,其余均为原发灶、转移灶生的变异。另有２例原发灶即有Ｐ５３变异者,在转移灶出现了新增加的变异。在３７处变异中,２７和为错义突变占７３．０％;６处为无义突变占１６     

Adenovirus-mediated p53 gene therapy in nasopharyngeal cancer

EBV-associated nasopharyngeal cancer (NPC) occurs with high frequency in China and is a major cause of morbidity and mortality. To explore the potential use of adenovirus-mediated tumor suppressor p53 gene therapy In NPC, we first examined the in vitro effects of p53 introduced into the NPC cell lines RPMI 2650, Fadu and Detroit 562. p21(WAF1/CIP1) induction by chemotherapy was used as a functional assay which revealed that RPMI 2650 expresses wild-type p53 whereas Fadu and Detroit 562 encode mutant p53. Infection with p53-expressing adenovirus (Ad-p53) induced apoptosis and inhibited cell growth in all three NPC cell lines, regardless of the endogenous p53 status. Adenovirus infectivity was greatest in RPMI 2650 cells, with 100% of the cells expressing beta-galactosidase following Ad-LacZ infection using an MOI of 100, as compared to 20-30% infectivity with the other NPC lines. Using RPMI 2650 cells injected into nude mice, we developed an animal model for nasopharyngeal cancer. Established tumors (0.6-0.8 cm) were injected with 5x10(9) PFU Ad-LacZ, Ad-p53 or PBS in a 100 mu l volume. We found evidence for in vivo expression of beta-galactosidase or p53 and p21 up to two weeks following Ad-LacZ or Ad-p53 virus injection respectively. Objective regression of tumor size was observed at two weeks in 4/6 Ad-p53-treated tumors, but not in Ad-LacZ or PBS-treated tumors. The results provide an animal model for human nasopharyngeal cancer, and indicate a potential use of p53 in its therapy in vivo.     

p53蛋白在非小细胞肺癌中的表达及意义

目的 :探讨非小细胞肺癌中p5 3蛋白的表达及意义。方法 :应用SP免疫组化法检测 5 2例肺癌组织中p5 3蛋白的表达。结果 :非小细胞肺癌中p5 3蛋白阳性表达率为 78 8% ,其中鳞癌与腺癌分别为 75 0 %和 82 1% ,p5 3蛋白阳性病人的预后较阴性者差。结论 :p5 3蛋白在非小细胞肺癌中有较高的表达 ,有可能作为评估预后、指导治疗的指标。     

原发性肝癌组织p53和ASPP2基因突变检测及临床意义

目的:检测原发性肝癌组织中p53与ASPP2基因突变,并探讨其临床意义.方法:收集24例肝癌标本,分别提取DNA及RNA,PCR扩增p53基因,逆转录PCR扩增ASPP2基因并进行半定量分析,基因测序后进行突变分析.结果:24例肝癌患者中,p53基因在肝癌组织中的突变率是75.0%,在癌旁组织中的突变率为20.8%,P<0.01;肝癌组织中ASPP2与GAPDH的灰度比值平均为0.81,癌旁组织中为0.85,P>0.05,但是癌组织和癌旁组织均未检测到ASPP2基因突变.结论:在原发性肝癌发生过程中,p53基因突变比ASPP2基因突变可能起到更重要的作用.