乳腺不典型增生组织中H—ras基因突变的检测

目的：探讨H-ras基因在乳腺癌发生早期的作用。方法：用PCR-RFLP和PCR-SSCP方法检测30例乳腺癌、36例单纯性增生、31例不典型增生组织中H-ras基因第12密码子的突变,用免疫组化技术检测乳腺癌和乳腺增生病组织中H-ras蛋白的表达。结果：73.3%的乳腺癌和48.4%的乳腺导管不典型增生组织有H-ras蛋白表达,单纯性增生上皮中无表达,所检测的增生病和乳腺组织中均未见到H-ras基因第12密码子突变。结论：H-ras蛋白过表达出现于乳腺癌发生的早期阶段,但这种过表达与H-ras基因第12密码子突变无关。     

乳腺癌发生过程中p53、BRCA1、BRCA2、PTEN、Rb蛋白异常表达

目的探讨p53、BRCA1、BRCA2、PTEN、Rb基因蛋白异常表达在乳腺癌发生中的作用。方法选取同时存在浸润癌、导管内癌、不典型增生和单纯性增生的乳腺癌档案蜡块,应用免疫组化S-P法检测p53、BRCA1、BRCA2、PTEN、Rb基因蛋白在各例的异常表达。结果(1)在24．3％(17／70)的乳腺癌及其癌旁不典型增生中检测到突变型p53蛋白表达,分别在2．9％(2／69)、6．3％(4／63)、5．1％(3／59)、5．4％(3／56)的乳腺癌及其癌旁不典型增生中分别检测到BRCA1、BRCA2、PTEN、Rb表达缺失。(2)在44．6％的病例同时检测到2种基因蛋白异常表达,在5．4％的病例同时检测到3种基因蛋白异常表达,在3．6％的病例同时检测到4种基因蛋白异常表达。结论(1)p53、BRCA1、BRCA2、PTEN、Rb蛋白异常表达可出现于乳腺癌发生的早期阶段,可能在乳腺癌发生过程中起作用。(2)多种抑癌基因的失活共同参与了乳腺癌的发生。     

p53基因第8外显子在喉癌中的缺失和点突变

目的 探讨抑癌基因p53第8外显子突变在喉鳞癌分子发病机理中所起的作用。方法 应用聚合酶链反应－单链构象多态性（PCR－SSCP）银染技术和DNA直接测序法,检测喉鳞癌新鲜组织中抑癌基因p53基因第8外显子的突变情况。结果 60例喉鳞癌组织中,15例发生迁移率异常的SSCP区带。在SSCP阳性样本中随机抽出4例进行测序分析,发现两个标本在288位密码子缺失一个A,两个标本在292位密码子上缺失一个A。285、287密码子上共发生3次G→T的颠换,286密码子第3位碱基发生A→T的颠换。结论 喉鳞癌p53基因点突变与碱基缺失常常同时并存。p53基因第8外显子突变在喉癌的发生中可能起着重要作用。     

PCR－SSCP技术一EB染色法检测胃癌中 P53基因第5～8外显子突变

PCR－SSCP技术一EB染色法检测胃癌中 P53基因第5～8外显子突变...     

大肠癌K-ras和p53基因序列分析

目的 研究大肠癌变与K－ras和p53基因突变的关系。方法 采用PCR－DNA双链四色荧光单道测序方法对31例大肠癌组织、13例大肠息肉伴不典型增生、11例大肠癌术后并发的腹水标本进行K－ras基因外显子1、2和p53基因外显子5、6、7、8测序分析。结果 31例大肠癌组织中发现K－ras基因突变7例，p53基因突变11例，阳性率分别为22.58%和35．48％;13例大肠息肉伴不典型增生组织中发现p53基因突变2例；11例术后腹水标本中发现K-ras基因突变1例和p53基因突变2例，且突变与患者原包埋组织结果一致。但未发现这两个基因同时突变的病例。结论 大肠组织癌变与这两个基因突变密切相关，K－ras和p53基因突变可能为大肠癌变的早期事件；DNA测序方法是研究癌基因突变的最精确可靠的方法。     

肝细胞癌病人中p53基因突变状况探讨

目的 了解肿瘤抑制基因p53在肝细胞癌中的突变情况,探讨乙型肝炎病毒（HBV）感染与p53基因突变之间的关系。方法 提取50例有乙型肝炎病毒感染史肝癌患者手术样本中的DNA,用聚合酶链式反应（PCR）扩增5－9外显子,作单链构象多态性（SSCP）分析。结果 p53基因突变率超过26％,突变主要分布于5－8外显子,5、6、7、8外显子分别有3、3、4、3例,另仍4个可疑突变。结论 p53基因突变可能是肝细胞癌的病因之一,而乙型肝炎病毒感染在中国肝癌患者p53基因突变中可能起到比较重要的作用。     

人巨细胞病毒感染的霍奇金淋巴瘤中p53基因突变分析

目的：检测人巨细胞病毒（HCMV）感染的霍奇金淋巴瘤（HL）中是否存在p53基因突变热点区的基因突变。方法：从经原位杂交、免疫组化、显微切割等方法证实存在人巨细胞病毒感染的霍奇金淋巴瘤石蜡标本中提取DNA，采用PCR－SSCP和核酸测序方法对p53基因突变热点区的外显子进行基因突变检测。结果：应用p53外显子5、6、7、8的相应引物，对10例HCMV阳性的HL组织中DNA进行PCR扩增，产物经电泳检测，分别扩增出特异的条带，SSCP分析未见异常的迁移带，ex-on-8外显子核酸测序未见有碱基突变。结论：p53基因热点突变区的基因突变在HCMV阳性的HL中可能是不常见的。     

p53基因在内分泌肿瘤形成中的作用:用PCR单链构象多态性检测突变

作者使用PCR-SSCP技术检测了134例原发性内分泌肿瘤和6株人内分泌肿瘤衍生细胞株中p53基因的突变。通过PCR扩增和SSCP技术检测p53基因,发现p53基因突变区域为外显子5到10,它包含了人肿瘤中大多数p53基因的突变区域。在所检的三株细胞株中没有移动的带与对照组类似,表明     

免疫组织化学-激光显微切割-聚合酶链反应技术在胃癌石蜡切片中检测p53突变的应用

目的 探索在石蜡切片中应用免疫组织化学-激光显微切割-聚合酶链反应(PCR)技术,检测进展期胃癌p53蛋白表达阴性或阳性的p53基因外显子5～8的突变情况。方法 对41例进展期胃癌标本进行p53蛋白的免疫组织化学标记,再用激光显微切割(LMD)技术切取p53表达一致的癌组织及远离癌灶的正常胃黏膜腺体。经消化后直接进行p53基因外显子5～8的PCR扩增、单链构象多态性分析及直接测序。结果 41例进展期胃癌标本均扩增出特异的目的条带。其中有11例p53蛋白表达阳性,15例p53基因检测到突变。蛋白表达阳性者中有8例突变(8／11);表达阴性者中有7例突变(7／30,23．3％)。p53蛋白表达和p53基因突变具显著相关(P=0．004)。结论 免疫组织化学-LMD-PCR技术应用于石蜡切片可获得满意的结果,此技术可将细胞特定基因的结构状态和表达水平很好地结合起来检测分析。     

乳腺癌和乳腺增生组织中TIMP-3基因突变谱研究

目的获得乳腺癌发生中TIMP-3基因的突变谱,探讨该基因突变与乳腺癌发生的关系。方法以50例乳腺癌及相应癌旁增生组织和正常乳腺组织、50例乳腺良性增生病变及15例正常人血淋巴细胞为研究对象,采用PCR-SSCP技术和DNA直接测序技术检测TIMP-3基因全部5个外显子的突变情况。结果在40/50例(80%)乳腺癌、36/50例(72%)相应的癌旁增生、40/50例(80%)乳腺良性增生病变,37/50(74%)例正常乳腺组织及13/15(86.67%)例正常人血液淋巴细胞中检测到TIMP-3基因外显子3突变,外显子1、2、4、5均未检测到突变,1～5号外显子的相应剪接点也未检测到基因序列改变。DNA测序证实上述外显子3的突变全部集中在249和261两个位点处,均为同义突变(249TC和261CT,对编码的氨基酸无影响),表明这两处位点的改变可能均为单核苷酸多态性。结论突变不是TIMP-3在乳腺癌中作用失活的主要原因,TIMP-3可能是以基因突变以外的其它方式在乳腺癌的发生发展过程中起作用。     

p53 protein expression and nuclear DNA content in breast intraductal proliferations

Immunohistochemical analysis of the p53 gene protein and cytometric assessment of nuclear DNA were performed in a series of 51 cases of intraductal breast proliferation. The series included 22 cases of intraductal hyperplasia without atypia, 6 cases of intraductal hyperplasia with atypia, and 23 cases of pure intraductal carcinoma. Expression of p53 protein was detected in one case of intraductal hyperplasia without atypia (4·5 per cent), one case of intraductal hyperplasia with atypia (16·6 per cent) and six cases of intraductal carcinoma (26·0 per cent). No significant correlation was observed between p53 expression and histological subtype of intraductal carcinoma. Aneuploidy was demonstrated in two cases of intraductal hyperplasia with atypia (33·3 per cent) and in 18 cases of intraductal carcinoma (78·2 per cent). All cases of intraductal hyperplasia without atypia were euploid. No significant association was observed between p53 protein expression and ploidy in intraductal hyperplasia. The only case of intraductal hyperplasia without atypia positive for p53 was euploid, whereas the only p53-positive case of intraductal hyperplasia with atypia was aneuploid. Among the intraductal carcinomas, only the aneuploid cases showed positivity for p53, regardless of histological subtype. The results suggest that some of the changes observed in invasive breast carcinoma, such as p53 expression and aneuploidy, are already present in breast intraductal proliferation, especially in areas with atypia and in intraductal carcinoma. The expression of p53 in breast intraductal proliferation may reflect the acquisition of p53 gene mutations in cells unable adequately to repair DNA damage, with genomic instability which would lead to clonal expansion and putative evolution to invasive disease.     

p53 mutations and expression in breast carcinoma in situ

The p53 tumor suppressor gene is altered in approximately half of human cancers. Although p53 mutations are common in invasive breast carcinoma, few have been identified in breast carcinoma in situ (intraductal breast carcinomas). Most studies of p53 in breast carcinoma in situ are immunohistochemical studies of p53 staining in paraffin-embedded tissue sections. Few studies have isolated the tumor cells and subjected them to DNA sequence analysis. The current study was undertaken to characterize p53 in a cohort of breast carcinoma in situ cases, both with and without invasive disease. Fifty-eight frozen breast biopsy samples were used for these investigations. Twenty-seven cases had only ductal carcinoma in situ (CIS) and 31 cases had evidence of both invasive and in situ carcinoma. DNA sequence alterations in exons 2 through 11 of p53 were screened by the single-strand conformational polymorphism technique. Exons with altered mobility were sequenced. Among breast CIS cases without invasive disease, 22% had p53 mutations and 7% had DNA sequence alterations of unknown significance. Analysis of breast CIS with concurrent invasive disease demonstrated p53 mutations in 19% of cases and one (3%) DNA alteration of unknown significance. Each carcinoma having a p53 mutation in the breast CIS component had the identical mutation in the invasive component of the same tumor indicating a clonal relationship between the two tumor components. p53 protein overexpression was identified in 22% of pure intraductal breast carcinomas and in 35% of breast CIS with invasive disease. Comparison of immunostaining and DNA sequence alterations showed a significant association between overexpression and mutations (P = 0. 0037) in cases of CIS without invasion, and similarly between overexpression and mutations in cases of CIS with invasion (P = 0. 007). p53 mutations and p53 overexpression were relatively common in intraductal breast carcinomas but were not observed in adjacent normal breast lobules or ducts in 9 cases available for DNA analysis. The frequency of p53 alterations when comparing breast CIS with and without an invasive component indicated that p53 mutations usually occur before invasion during the progression of breast cancer, as is observed for a number of other adult solid tumors.     

Expression of p53 protein in benign epithelial hyperplasia,atypical ductal hyperplasia,non-invasive and invasive mammary carcinoma: an immunohistochemical study

To clarify whether p53 protein expression is involved in multistep carcinogenesis or the progression of mammary ductal carcinoma, we investigated p53 protein expression in 83 invasive ductal carcinomas (IDC), 10 IDC with a predominant intraductal component, 13 non-invasive ductal carcinoma (NIDC), 16 atypical ductal hyperplasia (ADH) and 39 benign epithelial hyperplasia (EH), using immunohistochemistry. Expression of p53 protein was detected in 24 (28.9%) cases of IDC, 5 (50%) cases of IDC with a predominant intraductal component and 1 (7.6%) case of NIDC. No expression was observed in either ADH or EH. In IDC, including cases with a predominant intraductal component, p53 protein expression was associated with a higher histological grade (P<0.0001) or mitotic index (P<0.0005). Although overexpression of c-erbB-2 protein has also shown a similar association with these prognostic indicators, expression of p53 protein correlated regardless of the status of c-erbB-2 overexpression. Completely coordinated expression of p53 protein was seen in both intraductal and invasive components. The intraductal component in IDC including cases with a predominant intraductal component which expresses p53 protein had significantly higher histological grade (P<0.0005) or more comedo-subtypes (P<0.0001). These results suggested that p53 protein expression occurs at a stage of NIDC with high histological grade or in comedo-subtypes. Its expression is maintained throughout invasion.     

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     

p53基因第7外显子点突变与乳腺癌的关系

目的：研究ｐ５３基因点突变与乳腺癌发生发展关系。该当：应用多聚酶链反应－限制性片段长度多态性（ＰＣＲ－ＲＦＬＰ）检测７５例人乳腺癌标本ｐ５３基因第７外显子内２４８，２４９位密码子的点突变，结果：７５例乳腺癌标本ｐ５３基因第７外显子全长序列ＣＲ扩增产物经限制性内切酶ＭｓｐＩ酶切后，发现２例为突变型，用ＨａｅⅡ酶切后未发现有突变，结论：上述结果揭示ｐ５３基因第７外显子内２４８位密码子的突变为乳腺癌ｐ５     

人肺癌组织中p53,Rb基因突变研究

为探讨肺癌发生的分子遗传学机理，采用聚合酶链反应及聚合酶链反应－单链构象多态性技术，对４１例人肺癌组织中ｐ５３基因外显子５～８及Ｒｂ基因外显子１４～１６、２２～２３进行了突变分析。结果显示：ｐ５３基因突变１６例（１６／４１，３９％），分布于外显子５～７；Ｒｂ基因异常４例（４／４１，９．８％），其中外显子１４～１６区域部分缺失和外显子２２～２３区域突变各２例；在９例小细胞肺癌标本中，７例发生ｐ５３及Ｒ５基因的突变，其中１例存在ｐ５３基因两个外显子突变，另１例同时存在ｐ５３及Ｒｂ基因的突变。对部分ｐ５３基因突变标本序列分析，均在１个或３个密码子上存在导致ｐ５３蛋白异常的单碱基置换或插入突变。以上结果表明：肺癌、特别是小细胞肺癌的发生可能与ｐ５３及Ｒｂ基因的突变有关。     

Intraductal carcinoma is the precursor of carcinoma ex pleomorphic adenoma and is often associated with dysfunctional p53

AIMS: Although intraductal carcinoma has been demonstrated in intracapsular carcinoma ex pleomorphic adenoma (CEPA), the morphological and genetic stages of transformation of pleomorphic adenoma (PA) to CEPA are not fully understood. The aim of this study was to investigate the morphology of intracapsular CEPA. METHODS AND RESULTS: The largest series of intracapsular CEPA studied was subject to immunohistochemical double-staining to detect p53 protein and cellular proliferation in different types of cell combined with mutational analysis of the p53 gene in laser-microdissected material. Intraductal carcinoma with high-grade cellular atypia and frequent accumulation of p53 protein was found in 15/19 cases. Purely intraductal carcinoma was found in eight cases. Mutation of p53 was found in 7/19 cases, of which it was found in intraductal carcinoma in 5/15 cases. CONCLUSIONS: The frequent demonstration of intraductal carcinoma indicates that this preinvasive lesion is likely to be a constant feature in the malignant transformation of PA to CEPA. It appears to be a feature of CEPA developing from both primary and recurrent PA. The combined immunohistochemical and genetic data show that 14/19 cases of CEPA and 11/15 cases with intraductal carcinoma showed genetic or morphological evidence of dysfunctional p53, indicating that this is an early event in malignant transformation.     

肺鳞状细胞癌中p53蛋白表达及p53基因突变的检测

目的 通过检测肺鳞状细胞癌及癌旁组织中Ｐ５３蛋白积聚及相同癌组织中Ｐ５３基因的突变，探讨Ｐ５３蛋白积聚及Ｐ５３基因突变在肺鳞癌发病中的意义。方法 采用免疫组化和银染－ＰＣＲ－ＳＳＣＰ方法检测１２０例肺鳞癌及癌旁肺组织中Ｐ５３蛋白的状况及相同鳞癌组织中，Ｐ５３基因５、６、７、８外，显子突变的情况。结果 Ｐ５３蛋白了性率为５２．５％，Ｐ５３基因突变率为５６．７％，突变便数在第５、６、７、８外显子的分布     

K-ras gene mutations and loss of heterozygosity at the p53 gene locus relative to histological characteristics of mucin-producing tumors of the pancreas

Mucin-producing tumors (MPTs) of the pancreas accompanied by carcinomas usually include various grades of dysplasia in the ductal epithelium, and invasive areas are histologically similar to those of common invasive ductal carcinomas, suggesting that MPTs provide a good tool to investigate early stages of pancreatic carcinogenesis. Thus, to clarify genetic alterations in the early stage of pancreatic carcinogenesis, we analyzed K-ras gene mutations and loss of heterozygosity (LOH) at the p53 gene locus using 37 cases of MPTs harboring dysplastic epithelium. Further, we conducted an extended, multifocal microdissection analysis focusing on the histological features of ductal epithelium and the distribution of genetic alterations for 3 cases of MPT positive for LOH of the p53 gene to determine the relation to tumor progression. K-ras gene mutations were detected with high frequency in 50% or more cases of the adenomas (14 of 19), borderline tumors (4 of 7), and carcinomas (8 of 11), whereas LOH of the p53 gene was limited to carcinomas (3 of 5 informative cases, 60%) and always accompanied by K-ras gene mutation. Investigation of a total of 126 microdissection sites from 3 cases showed the presence of K-ras gene mutations in mild dysplasia and all (100%) regions of moderate or more marked dysplasia, whereas LOH of the p53 gene showed more gradual tendency to increase with grade from moderate dysplasia. In addition, the multifocal genetic analysis showed K-ras gene mutations to be widely distributed throughout tumors, whereas LOH of the p53 gene was localized to 1 or a few areas. Further, topographically delimited areas with the same histology in the same tumor did not always show the same genetic alteration. In conclusion, we could confirm that both the K-ras and p53 gene alterations occur in the intraductal stage of MPT, and the latter is superimposed on the former during the course of tumor progression. However, the pattern of association of histological features with genetic alteration differs from tumor to tumor.