p53 expression and DNA ploidy pattern in Egyptian colorectal carcinoma

BACKGROUND/AIMS: p53 gene mutation occurs in about 50-60% of colorectal carcinoma cases. This mostly occurs as a late event in the adenoma-carcinoma sequence. These late stages are associated with more aneuploidy compared to adenomas and early carcinomas. However there is a controversy regarding the relation between p53 overexpression and DNA index. This study was designed to investigate the relationship between p53 status and DNA ploidy pattern. METHODOLOGY: Nuclear DNA content of paraffin-embedded material from 83 colectomy specimens for colorectal carcinoma was measured by flow cytometry. Also, p53 was detected by immunohistochemistry in 73 out of the 83 tumor cases using a monoclonal antibody that detects both wild and mutant p53 proteins (Biogenex 1801). RESULTS: Aneuploidy was identified in 37 cases (46.25%). Tumors with rectal location were significantly more aneuploid in comparison to other sites (P = 0.009), p53 staining showed three patterns: diffuse staining (29 cases), focal (13 cases), and negative (31 cases). Diffuse p53 staining was associated with aneuploidy (P = 0.04). The majority of DNA indices fell within the range 1.1-2.2 (32 out of 37). Twenty-one of these had DNA index = 1.1-1.8 (aneuploidy short of tetraploidy) significantly associated with diffuse p53 staining compared with peritetraploid cases (DNA index 1.8-2.2) (P = 0.034). CONCLUSIONS: p53 immunohistochemistry demonstrates two distinct patterns in colorectal carcinoma. Diffuse p53 staining, which is associated with aneuploidy short of tetraploidy (DNA index 1.1-1.8), a finding which is different from previously published work. Focal p53 staining pattern, in contrast, is related to high G2M and more abnormal tetraploid peaks but less aneuploidy.     

p53 gene mutations in soft-tissue sarcomas-correlations with p53 immunohistochemistry and DNA ploidy

The significance ofp53 mutations in a group of 67 soft-tissue tumors was examined using single-strand conformation polymorphism and direct sequencing analysis. Molecular findings were correlated with immunohistochemical detection of thep53 protein and DNA ploidy status. Mutations of thep53 gene were detected in 13 (19.5%) out of 67 cases of soft-tissue tumors. Only there were localized outside the conservative regions of thep53 gene. Six mutations were described for the first time in these tumors. Most of the mutations were point mutations in exons 5–8 and, in one case, a deletion at the 3-splice site of exon 5 could be demonstrated. There was no significant correlation between the occurrence ofp53 mutations and the histological grade, although a high number of mutations were defined in poorly differentiated tumors (grade 3). Molecular finding of ap53 gene mutation and immunohistochemical detection ofp53 expression did not correlate, which may be due to the high percentage of nonsense mutations in our study (50%). We confirm that only DNA sequencing allows a unique identification and differentiation of mutations in thep53 gene. Other factors may be responsible for the detection ofp53 protein in many cases. Histological grade correlated with aneuploidy. The frequency of mutations observed was in accordance with values quoted in the literature. Generally,p53 mutations andp53 overexpression are more likely to represent a late event in the oncogenesis of soft-tissue tumors.     

DNA ploidy of colorectal carcinoma. Correlation with conventional prognostic variables

The DNA content of tumor cells was determined in 51 cases of colorectal carcinoma and correlated with conventional clinicopathologic features. Normal diploid content of DNA was found in cells from 19 tumors, and aneuploidy was found in cells from 32 tumors. An aneuploid stemline of tumor cells appeared to be associated with advanced disease. However, a statistical analysis using Pearson's chi-square test disclosed no significant correlation between DNA ploidy of tumor cells and conventional clinicopathologic characteristics of colorectal carcinoma, such as differentiation, staging, lymph node status, and depth of invasion.     

大肠癌p53、K-ras基因突变研究

目的：探讨p53,K-ras基因突变与大肠癌发生、发展的关系。方法：应用PCR－SSCP方法研究68例大肠癌和癌旁组织以及20例正常组织p53,K-ras基因突变情况。结果：大肠癌组中p53，K-ras基因突变率分别为47．1％和44．1％，明显高于癌旁组（分别为13．2％和7．4％），20例正常组织中未检出p53、K-ras基因突变，大肠癌伴有淋巴结转移及远处转移，p53、K-ras基因突变率明显高于无淋巴结及远处转移；p53、K-ras基因突变与组织学分型无关。结论：p53、K-ras基因突变与大肠癌发生、发展有密切关系，在细胞癌变中起重要作用，可作为评估大肠癌转移的分子生物学指标。     

p53 immunostaining pattern in Brazilian patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an important type of cancer etiologically related to some viruses, chemical carcinogens and other host or environmental factors associated to chronic liver injury in humans. The tumor suppressor gene p53 is mutated in highly variable levels (0-52%) of HCC in different countries. OBJECTIVE: The objective of the present study was to compare the frequency of aberrant immunohistochemical expression of p53 in HCC occurring in cirrhotic or in non-cirrhotic patients as well as in liver cell dysplasia and in adenomatous hyperplasia. We studied 84 patients with HCC or cirrhosis. RESULTS: We detected p53 altered immuno-expression in 58.3% of patients in Grade III-IV contrasting to 22.2% of patients in Grade I-II (p = 0.02). Nontumorous areas either in the vicinity of HCC or in the 30 purely cirrhotic cases showed no nuclear p53 altered expression, even in foci of dysplasia or adenomatous hyperplasia. No significant difference was found among cases related to HBV, HCV or alcohol. CONCLUSION: The high frequency of p53 immunoexpression in this population is closer to those reported in China and Africa, demanding further studies to explain the differences with European and North American reports.     

胃癌中VEGF及突变型p53基因表达及临床意义研究

目的探讨血管内皮生长因子(VEGF)及突变型p53(mtp53)基因表达水平与胃癌病理生理学特征之间的关系。方法采用免疫组化方法(二步法),检测86例胃癌组织及30例癌旁组织及切缘"正常"组织中的VEGF、mtp53表达水平。结果胃癌组织中VEGF、mtp53基因的表达水平显著高于癌旁组织和切缘"正常"组织(P0.01)。VEGF、mtp53基因表达水平与胃癌患者性别、年龄、组织学类型、细胞分化程度均无明显关系(P0.05),与浸润程度、淋巴结转移、远处转移状态、P-TNM分期均有密切关系(P0.01)。mtp53基因表达水平与VEGF表达水平呈正相关(P0.01)。结论VEGF、mtp53基因可能参与了胃癌的发生、进展进程,可以作为胃癌生物学行为恶化的一项指标。     

Expression of mutant p53 protein in hepatocellular carcinoma.

p53 mutations are a common genetic finding in hepatocellular carcinoma from areas of high aflatoxin exposure. Recent small studies have shown that p53 gene mutations may be less common in areas with a low prevalence of hepatocellular carcinoma such as Great Britain. The protein product of mutant p53 can be detected immunohistochemically because of its longer half life in comparison with native protein. This study used a novel monoclonal antibody DO-7, raised against recombinant p53 and effective in routinely processed biopsy specimen tissue, to detect the mutant protein in a series of 45 cases of hepatocellular carcinoma occurring in white subjects resident in the United Kingdom. Focal nuclear labelling was seen in four cases (9%); surrounding cirrhotic tissue in one of these was negative for p53 expression. This study shows that p53 mutations are a rare event in hepatocarcinogenesis in Great Britain, an area of low aflatoxin exposure, and supports the concept of geographical variations in the cause and pathogenesis of hepatocellular carcinoma.     

Prognostic influence of p53 nuclear overexpression in colorectal carcinoma

PURPOSE: The aim of this study was to test the prognostic influence of p53 nuclear overexpression in colorectal carcinoma. METHODS: We performed an analysis of the prognostic influence of the nuclear overexpression of p53 with immunohistochemistry in 126 cases of colorectal carcinoma operated on in our hospital between 1987 and 1992, with a minimum follow-up time of 60 months (5 years). RESULTS: Our results show a statistically significant prognostic influence of p53 overexpression on disease-free survival time, but not on the overall survival time, in univariate analysis, but this influence is lost in multivariate analysis. CONCLUSIONS: Our results confirm recent reports by other authors that failed to show the independent prognostic value of p53 in colorectal carcinoma.     

Serum p53 antibody assay: evaluation in colorectal cancer

INTRODUCTION: Alterations of the tumor suppressor gene p53 and its protein synthesis is the most commonly observed genetic feature in human cancers. Direct diagnosis of the gene mutation using sequencing is the gold standard method. However, it requires advanced technology and is only performed in specialized research units. CURRENT KNOWLEDGE AND KEY POINTS: Demonstration of intratumoral p53 protein accumulation using immunohistochemistry is a routine diagnostic technique. Serum detection of p53 antibodies using ELISA has been recently developed. It is an easily feasible and reproducible method for the diagnosis of p53 alterations due to self-immunization in some patients in response to intratumoral p53 protein overexpression. This phenomenon is inconstant (about one-third of the patients with a p53 gene mutation produce antibodies) and its mechanism is unclear. p53 Antibodies are found in 25% of the patients with colorectal cancer, independently of traditional tumor markers (carcinoembryonic antigen and carbohydrate antigen 19.9). The presence of these antibodies is not linked to the tumor stage. Since their ratios vary during the treatment, they might constitute a new tumor marker. FUTURE PROSPECTS AND PROJECTS: Early appearance of p53 serum antibodies during tumor development should make them useful for the detection of malignant transformation in patients with preneoplastic disease such as ulcerous colititis. Whether the presence of p53 antibodies in colorectal cancer patients has a prognostic significance requires further assessment.     

p53、K-ras基因对大肠癌血管生成的调控作用

目的　探讨p53、K ras基因对大肠癌血管生成的调控作用。方法　用PCR 单链构像多态性分析 (SSCP)和免疫组织化学的方法研究 68例大肠癌和癌旁组织以及 2 0例正常组织p53、K ras基因突变及血管内皮生长因子 (VEGF)和微血管密度的表达情况。结果　大肠癌组中p53、K ras基因突变率及VEGF的表达明显高于癌旁组 ,2组的阳性率分别为 47 1 % ,44 1 % ,55 9% (32 /68,30 /68,38/68) ;1 3 2 % ,7 4% ,1 1 8% (9/68,5/68,8/68)。 2 0例正常组织中未检出p53、K ras基因突变及VEGF的阳性表达。VEGF的表达与大肠癌的血管生成和转移显著相关 (r =0 82 0 ,P <0 0 1 )。p53、K ras均与VEGF表达显著相关 (P <0 0 1 )。结论　p53、K ras基因可上调VEGF的表达 ,p53、K ras基因在调控大肠癌血管形成方面起重要作用     

survivin基因在大肠癌组织中的表达及其与bcl-2和p53基因的相关性探讨

目的 探讨survivin在大肠癌组织中的表达及其与bcl-2、p53基因表达的相关性。方法 应用免疫组织化学方法检测大肠腺癌组织中survivin及bcl-2、p53的表达,并与其在正常大肠黏膜、增生性息肉及腺瘤组织中的表达进行比较。结果survivin在正常大肠黏膜无表达,大肠腺瘤（62.5%）、大肠癌（70.9%）中survivin表达率显著高于正常大肠黏膜和增生性息肉（16.7%）（P〈0.01）;survivin表达与与肿瘤浸润深度和淋巴结转移明显相关（P均〈0.05）;大肠癌组织中bcl-2、p53基因与survivin基因表达显著相关（P均〈0.05）。结论 survivin参与了大肠癌的发生和发展,可作为判断预后的参考指标;抑癌基因p53的失活和bcl-2的表达上调与survivin基因的表达可能在大肠癌的发生、发展中起协调作用。     

结肠癌合并血吸虫感染患者癌细胞p53基因的表达

目的 研究原发性结肠癌细胞p53基因mRNA的表达水平及合并血吸虫感染后的差异,探讨其与患者临床病理特征的关系。 方法 38例原发性结肠癌患者分为两组,A组（合并血吸虫感染）20例和B组（未合并血吸虫感染）18例。应用实时荧光定量 PCR和相对定量分析法检测患者肿瘤组织中的p53 mRNA。 结果 p53 mRNA在两组中均可检出,A组中的基因表达水平显著高于B组（P＜0.05）。p53基因mRNA表达水平与年龄、性别相关无显著性,与肿瘤大小、有无淋巴结转移相关具有显著性。结论 p53基因mRNA的高水平表达与结肠癌的侵袭和发展具有显著性差异,血吸虫感染可能对结肠癌患者p53基因的突变有一定影响。     

粪便p53基因突变检测在结直肠癌诊断中的应用

目的 探讨粪便p53基因突变检测对结直肠癌的诊断价值,旨在建立一种非侵入性的结直肠癌筛检的方法。方法 应用PCR-单链构象多态性分析-溴乙锭染色方法,检测40例结直肠癌、20例结直肠腺瘤及15例胃癌患者肿瘤组织和粪便标本p53基因突变。结果 40例结直肠癌患者粪便p53相应外显子DNA片段扩增率为90％,20例结直肠腺瘤为85％,15例胃癌为93％。所有标本总的扩增率为89％。40例结直肠癌患者组织标本中29例存在p53突变(72．5％),其中23例粪便测及p53突变,检测敏感性为57．5％,明显高于粪便隐血及血癌胚抗原检测的阳性率(P＜0．05);20例结直肠腺瘤患者组织标本中3例存在p53突变(15．0％),且均测及粪便p53基因突变。15例胃癌患者组织标本中10例存在p53突变(67．7％),粪便均未测及p53突变。结论 粪便p53基因突变检测诊断结直肠癌的敏感性较高,有望成为早期诊断大肠癌的一个相对敏感、特异、有效的指标,尤其在大范围人群筛检时。     

DNA ploidy pattern in rectal carcinoid tumors

The nuclear DNA pattern of 22 rectal carcinoids was determined by cytophotometry of paraffin embedded tissues. The results were compared with clinical as well as histopathologic features of the tumor. Three of the carcinoids with synchronous or metachronous metastasis had aneuploid DNA pattern, whereas 19 tumors with no metastasis showed diploid DNA pattern. No other single clinical or pathologic feature of the tumor could predict more accurately the malignant potential and the subsequent course of the rectal carcinoid. It is concluded that DNA aneuploidy in rectal carcinoid tumors is not so rare as indicated by earlier studies and that it is a factor of significant prognostic value.Dr. George Tsioulias is a recipient of the Monbusho Scholarship (Japanese Ministry of Education).     

Serum carcinoembryonic antigen in relation to survival, DNA ploidy pattern, and recurrent disease in 406 colorectal carcinoma patients.

Serum carcinoembryonic antigen (CEA) levels in relation to survival, flow cytometric DNA ploidy pattern, Dukes stage, and recurrent disease was prospectively evaluated in 406 patients with colorectal carcinoma. In 246 patients (61%) the carcinomas were DNA aneuploid. Increased preoperative CEA levels (> 5 micrograms/l) were found in 151 of 363 evaluable patients (42%). Dukes stage-B patients with preoperative CEA elevation showed significantly poorer prognosis than those with normal CEA values (p = 0.001). A weak but significant correlation was found between preoperative CEA level and Dukes stage (Kendall's tau = 0.25, p < 0.01). Of 50 evaluable patients with clinical recurrence and postoperative normal or normalized CEA levels, 28 (56%) had a rise in CEA before or at the time of clinical recurrence. The sensitivity of the CEA test for primary and for recurrent disease was not significantly different in the DNA aneuploid and the DNA near-diploid groups.     

锤头状核酶对肝癌突变基因p53的抑制作用

目的 探讨p53核酶对肝癌细胞突变型抑癌基因p53的抑制作用。方法 应用计算机设计并合成针对突变型p53(249位密码子AGG→AGT)的锤头状核酶RZ，构建其体外转录和真核表达载体，检测核酶对突变型p53(mtp53)的体外切割作用，并在Lipofect AMINE^TM2000的介导下转染肝癌细胞MHCC97，应用逆转录聚合酶联反应(RT—PCR)检测核酶对肝癌细胞突变型p53的抑制作用。结果 测序证实核酶基因被正确克隆人体外转录载体pBSKU6和真核载体pEGFPC1中。体外切割效率为42％，而野生型p53(wtp53)没有被切割。在Lipofect AMINETM2000的介导下成功转染肝癌细胞MHCC97，RT—PCR检测证实突变型p53的mRNA水平明显下降，细胞内的切割效率为69％。结论 p53核酶可成功抑制肝癌细胞中突变型p53的表达，为肝癌的基因治疗提供了一个新的选择。     

bcl-2与p53在大肠腺瘤和大肠癌中的表达

目的探讨原癌基因ｂｃｌ２与抑癌基因ｐ５３在大肠腺瘤和大肠癌中的表达变化与大肠腺瘤和大肠癌的发生、发展的关系，以及ｂｃｌ２与ｐ５３在大肠癌中的表达变化与大肠癌的临床病理特征间的关系．方法采用免疫组化ＡＢＣ法，分别检测ｂｃｌ２在３３例大肠腺瘤和４７例大肠癌中的表达变化和ｐ５３在４０例大肠腺瘤和６３例大肠癌中的表达变化．结果ｂｃｌ２在大肠腺瘤和大肠癌中的阳性表达分别为７２７％（２４／３３）和３４０％（１６／４７）．ｐ５３在大肠腺瘤和大肠癌中的阳性表达分别为４５０％（１８／４０）和８４１％（５３／６３），ｂｃｌ２和ｐ５３在大肠腺瘤和大肠癌中的表达有显著性差异（Ｐ＜００１），但其表达变化与大肠癌的临床病理特征关系不明显（Ｐ＞００５）．结论ｂｃｌ２表达在腺瘤向癌的演变过程中丢失，而ｐ５３表达则增加（Ｐ＜００１），表明它们参与了肿瘤生长和发展的共同通道，在大肠癌的发生、发展和演变过程中起着重要作用     

Clinical significance of immunohistochemical study of p53 protein in colorectal carcinoma

AIM: To determine the clinical significance of p53 protein expression in colorectal carcinoma. METHODS: The expression of p53 protein was examined in 92 colorectal carcinomas using the monoclonal antibody PAb 1801. Correlation between p53 protein expression and prognosis in colorectal carcinoma was analyzed using the log-rank test. RESULTS: The frequency of p53 protein expression was 57.61%, corresponding with Dukes' stage of bowel cancer. Analysis of survivor data demonstrated that the survival rate of the colorectal carcinoma with positive staining for p53 protein was lower than that of group with negative staining. CONCLUSION: Expression of p53 protein is correlated with poor prognosis in colorectal carcinoma.