中国人大肠癌K-ras基因突变的研究

目的：检测K－ras基因在国人散发性大肠癌中的突变情况,探讨K-ras基因突变在中国人大肠癌中的特点以及与临床病理参数的关系。方法：微解剖取正常粘膜组织15例、癌组织35例、PCR扩增、DNA测序、检测K－ras第12、13和61密码子的突变情况。结果：癌组织K－ras突变率为14．3％（5／35）,均发生在第12密码子（GGT→GAT）。第13和61密码子无突变,正常粘组织无K－ras突变。伴有12密码子突变的大肠癌患者年龄较大,大体以隆起型为主,均分布在C和D期,有较强的侵袭性。结论：中国人大肠癌K-ras突变率为14．3％,低于欧美国家且仅发生在第一外显子的12密码子的第二碱基。大肠正常粘膜无K－ras突变。K-ras突变与患者的年龄、肿瘤的大体形态和Dukes分期等临床病理参数有关。     

卵巢癌p53基因第7,8外显子突变的研究

为了解ｐ５３基因与卵巢癌的关系，采用ＰＣＲ产物－直接测序技术，初步分析了１５例卵巢恶性肿瘤ｐ５３基因第７、８外显子的突变。结果有２例第７外显子的２５２位密码子发生改变。１例为缺失第３位碱基Ｃ导致移码突变，另一例为第２位碱基Ｔ→Ａ颠换，导致错义突变。提示２５２位密码子可能在中国人卵巢癌中突变率较高，且易发于浆液性囊腺癌。     

卵巢癌中k-ras 基因点突变及p53蛋白表达

目的 探讨k—ras基因点突变和p53蛋白表达在卵巢癌发生中的作用及致癌机制。方法 采用显微切割技术、半巢式PCR—RFLP技术和免疫组化染色检测55例卵巢癌及其交界性病变中的k—ras基因点突变和p53蛋白表达。结果 k-ras基因点突变率在黏液性腺癌(61．9％)明显高于浆液性腺癌(14．2％),在黏液性交界性腺瘤(61．5％)明显高于浆液性交界性腺瘤(12．5％)。p53蛋白表达率在浆液性腺癌(80％)明显高于黏液性腺癌(52％),并随组织学分级而增高。结论 黏液性腺癌主要通过腺瘤-交界性腺瘤-腺癌途径致癌,k—ms基因点突变是黏液性腺癌的早期事件,黏液性交界性腺瘤是黏液性腺癌的癌前病变。浆液性腺癌主要通过生发上皮直接恶性转化形成,p53蛋白表达在浆液性腺癌的发生中起重要作用,是浆液性腺癌的晚期事件。     

卵巢微乳头浆液性交界瘤4例临床病理分析

1996年Burks[1]报道在卵巢浆液性交界瘤内有一类微乳头状交界瘤,肿瘤虽无明显卵巢间质浸润,但常伴有浸润性腹膜种植,病变多进行性发展为浸润性肿瘤.Burks称其为卵巢微乳头浆液性癌(micropapillary serous carcinoma, MPSC).此后许多学者[2～4]对MPSC进行了研究,并提出了不同的看法.Deavers[5]认为MPSC常伴浸润性种植,复发率高,但其总生存率和浆液性交界瘤相当,因而将它保留在交界的范围内是正确的.我们复查了近10年来诊断为卵巢浆液性交界瘤和卵巢浆液性癌的病例,发现符合MPSC的诊断标准有4例,本文称之为微乳头浆液性交界瘤(micropapillary serous borderline tumors, MSBTs),现将其临床病理学特点报道如下.     

卵巢黏液性交界性肿瘤中K-ras基因突变及p21 ras蛋白的表达

目的：观察卵巢黏液性交界性肿瘤中K-ras基因突变及p21 ras蛋白的表达,探讨卵巢黏液性交界性肿瘤的发病机制及靶基因治疗的可能。方法采用PCR-RFLP法和免疫组化EliVision法分别检测40例卵巢黏液性交界性囊腺瘤、40例卵巢黏液性囊腺癌和20例卵巢黏液性囊腺瘤中K-ras基因突变和p21 ras蛋白的表达。结果 K-ras基因在卵巢黏液性囊腺瘤、黏液性交界性囊腺瘤和黏液性囊腺癌中的突变率分别为0、37.5%、7.5%,交界组突变率明显高于其他两组,差异有统计学意义( P<0.01)。 K-ras基因突变在卵巢黏液性交界性肿瘤年龄分组中突变,差异有统计学意义(P<0.05)。 p21ras蛋白在卵巢黏液性囊腺瘤、黏液性交界性囊腺瘤和黏液性囊腺癌中阳性率分别为5%、45%、10%,交界组阳性率明显高于其他两组,差异有统计学意义(P <0.01)。结论 K-ras基因突变及p21ras蛋白表达可能是卵巢黏液性交界性肿瘤形成的原因之一,有利于卵巢黏液性交界性肿瘤的判断,还可为临床作为靶向治疗药物分析提供病理学基础。     

子宫内膜癌与K-ras基因突变的研究

目的:分析子宫内膜癌组织中K-ras基因突变状况及其与Ras蛋白表达的相关性,从基因水平探讨K-ras基因在子宫内膜癌发病中的作用机制.方法:诊断明确的子宫内膜癌手术切除标本108例及同期因其他病因行刮宫术的正常子宫内膜.应用免疫组织化学染色法检测K-ras的表达,PCR扩增-直接测序法检测K-ras基因第2外显子12、13密码子突变,分析K-ras基因突变对Ras蛋白表达的影响及临床意义.结果:K-ras蛋白阳性表达率在子宫内膜癌明显高于正常子宫内膜;子宫内膜癌中K-ras基因突变率为33.3%;其中第12位密码子突变占75.0%,突变位点均位于K-ras基因第12位密码子第2位碱基上;第13位密码子突变率为25%,突变位点位于K-ras基因第13位密码子第1、2位碱基上.K-ras基因突变与Ras蛋白表达成正相关.结论:K-ras蛋白的阳性表达率可能是预示子宫内膜癌预后的一个因素,K-ras基因12密码子G→T和G→A突变是主要的突变方式.12密码子的突变可能为Ras蛋白增多的原因.     

卵巢浆液性交界瘤近期讨论的诊断问题

卵巢浆液性交界瘤（serous-borderline ovarian tumrs．SBOT）肿瘤分型、腹膜种植以及浆液性癌的诊断一直意见不一。2003年在美国Bethesda成立了卵巢交界瘤工作组,对以往文献中报道的卵巢交界瘤的报道资料进行了分析。Bell认为卵巢浆液性微乳头交界瘤（micripapillary type serons-bordedine ovarian tumors）与典型的S-BOT比较,差异不明显,因而将前者留在交界瘤范围内比较适当。     

卵巢浆液性肿瘤中MCM4与Ki-67的表达及意义

目的 探讨微小染色体维持蛋白4(minichromosome maintenance proteins 4,MCM4)、Ki-67在卵巢浆液性肿瘤中的表达及意义.方法 采用免疫组化EliVision两步法检测MCM4、Ki-67蛋白在10例正常卵巢上皮组织(对照组)、19例卵巢良性浆液性嚢腺瘤、16例交界性浆液性肿瘤和43例浆液性腺癌中的表达.结果 MCM4在对照组、卵巢良性浆液性囊腺瘤、交界性浆液性肿瘤、浆液性腺癌的阳性表达率分别为10.00%、21.05%、43.75%、79.07%,Ki-67在对照组、卵巢浆液性乳头状腺瘤、交界性嚢腺瘤、浆液性腺癌的阳性表达率分别为10.00%、15.79%、25.00%、53.49%,其随着卵巢肿瘤病变的升级呈增高的趋势.MCM4在卵巢浆液性腺癌和交界性浆液性肿瘤中的表达与正常对照组相比差异具有统计学意义(P<0.05).Ki-67在卵巢浆液性癌和交界性浆液性肿瘤中的表达与正常对照组相比差异具有统计学意义(P<0.05).MCM4在卵巢浆液性癌中的表达与临床分期、病理分级及转移[淋巴结转移和(或)器官转移]有明显相关(P<0.05).Ki-67蛋白在卵巢浆液性癌中的表达与病理分级及淋巴结转移有明显相关(P<0.05),MCM4和Ki-67呈正相关.结论 MCM4、Ki-67为卵巢浆液性肿瘤的增殖指标,用于卵巢良、恶性肿瘤的鉴别和诊断,并可初步评估肿瘤预后,指导临床治疗.     

特异引物双扩增即时PCR与传统测序法检测肠癌、肺癌患者K-ras基因突变的比较

目的 以特异引物双扩增即时PCR技术K-ras检测试剂盒(下称ADx-K-ras即时PCR试剂盒)和Sanger DNA测序法同时检测结直肠癌和肺癌患者K-ras基因,以了解K-ras基因突变频率和突变类型,比较ADx-K-ras即时PCR试剂盒和Sanger DNA测序法用于肿瘤K-ras基因体细胞突变检测的临床价值.方法 收集临床肿瘤病理石蜡切片样品827例,其中肠癌样品583例,肺癌样品244例,提取DNA后,对K-ras基因第12和13密码子进行PCR扩增后,使用ADx-K-ras即时PCR试剂盒进行检测,与此同时,将PCR扩增后的产物进行Sanger DNA测序.两种方法对K-ras基因第12和13密码子的检测结果进一步进行各个突变类型的数目和突变率的统计对比.结果 ADx-K-ras即时PCR试剂盒对827例样品检测都得到了明确的结果,检测成功率为100%,Sanger DNA测序成功检测了677例,成功率为81.9%.583例肠癌样品中ADx-K-ras即时PCR试剂盒检测出突变192例,突变检出率为32.9%,Sanger DNA测序成功的样品533例,检出突变160例,突变检出率为30.0%.244例肺癌样品中ADx-K-ras即时PCR试剂盒检出突变26例,突变检出率为10.7%,Sanger DNA测序成功的样品144例,检出突变12例,突变检出率为8.3%.肠癌中第12密码子第2位的GGT→GAT最常见,占全部突变的35.1%(66/188),其次是第13密码子第2位的GGC→GAC,26.6%(50/188),第12密码子第2位的GGT→GTT,18.6%(35/188),第12密码子第1位的GGT→GCT最少见,1.6%(3/188).肺癌中第12密码子第1位的GGT→GTT最常见,占全部突变的40.9%(9/22),同样第12密码子第1位的GGT→GCT最少见,占全部突变的4.5%(1/22).结论 肠癌中K-ras突变率明显高于肺癌.对于甲醛固定石蜡包埋样品而言,ADx-K-ras即时PCR试剂盒对样品的DNA质量的耐受性较好,检测成功率高于Sanger DNA测序,可替代Sanger DNA测序法成为临床上对肿瘤K-ras基因体细胞突变检测的实用方法.     

P16、P53和CyclinD1蛋白在卵巢浆液性肿瘤中的表达及意义

目的 探讨浆液性卵巢上皮性肿瘤中P16、P53和CyclinD1蛋白的表达情况及意义.方法 应用免疫组化法对2010-2011年本院45例浆液性卵巢癌(低级别19例,高级别26例)、25例卵巢交界性浆液性囊腺瘤及21例卵巢浆液性囊腺瘤组织进行P16、P53、CyclinDl蛋白检测,并分析其临床病理意义.结果 P16在良性、交界性与癌组的阳性表达率分别为24％、72％及89％,良性肿瘤组与交界性和癌组之间差异有统计学意义(P＜0.05).P53在良性、交界性与恶癌组的阳性表达率分别为5％、4％及42％,良性和交界性肿瘤组与癌组之间差异有统计学意义(P＜0.05).CyclinD1在良性、交界性与癌组的阳性表达率分别为10％、64％及47％.良性肿瘤组、交界性肿瘤组与癌组之间差异均有统计学意义,P＜0.05.P53、CyclinD1在卵巢浆液性癌高低级间别比较差异均有统计学意义,两者表现为负相关,r=0.211.结论 P16的阳性表达常见于卵巢交界性浆液性囊腺瘤和卵巢浆液性癌中,P53的阳性表达更多见于高级别卵巢浆液性癌中,CyclinD1的阳性表达更多见于卵巢交界性浆液性肿瘤与低级别浆液性癌组织中.卵巢高级别癌与低级别癌的发病机制不同.     

Diverse tumorigenic pathways in ovarian serous carcinoma

This study was undertaken to analyze genetic alterations in 108 sporadic serous ovarian neoplasms to elucidate ovarian serous carcinogenesis. Our results demonstrate that K-ras mutations occur in approximately 50% of serous borderline tumors (SBTs), non-invasive micropapillary serous carcinomas (MPSCs), and invasive micropapillary serous carcinomas, which represent a morphological continuum of tumor progression. Moreover, progressive increase in the degree of allelic imbalance of chromosomes 1p, 5q, 8p, 18q, 22q, and Xp was observed comparing serous borderline tumors to noninvasive and invasive micropapillary serous carcinomas. In contrast, high-grade (conventional serous carcinoma) tumors contained wild-type K-ras in all 23 cases studied and a high frequency of allelic imbalance even in small (early) primary tumors similar to that found in advanced stage tumors. Based on these findings, we propose a dualistic model for ovarian serous carcinogenesis. One pathway involves a stepwise progression from SBT to noninvasive and then invasive MPSC. The other pathway is characterized by rapid progression from the ovarian surface epithelium or inclusion cysts to a conventional (high-grade) serous carcinoma.     

K-ras activation occurs frequently in mucinous adenocarcinomas and rarely in other common epithelial tumors of the human ovary.

To explore the role of mutational activation of members of the ras family of cellular protooncogenes in the development of human ovarian neoplasms, a series of 37 ovarian tumors from Japanese patients was studied. These included 30 common epithelial tumors (1 mucinous tumor of borderline malignancy, 7 mucinous adenocarcinomas, and 22 nonmucinous carcinomas: 10 serous, 3 clear cell, 8 endometrioid, and 1 undifferentiated), 5 tumors of germ cell origin, and 2 sex cord/stromal cell tumors. Polymerase chain reaction was performed from selected areas of deparaffinized sections of formalin-fixed paraffin-embedded tissue, and the presence of activating point mutations in codons 12, 13, and 61 of the H-, N-, and K-ras genes was probed by dot-blot hybridization analysis with mutation specific oligonucleotides. Mutations in K-ras were also looked for by direct genomic sequencing. The overall frequency of ras gene mutations was 10/37 (27%). Mutations were detected only in K-ras, and were found in most of the mucinous tumors, including the one such tumor of borderline malignancy (6/8; 75%). In one mucinous adenocarcinoma, two mutations were detected in paraffin-embedded material that had not previously been found in high molecular weight DNA isolated from frozen tissue from the same case. K-ras mutations occurred significantly more frequently in mucinous tumors (6/8, 75%) than in serous carcinomas (2/10, 20%; P = 0.031) or in all nonmucinous types of epithelial ovarian tumors combined (3/22, 14%; P = 0.0031).     

Incidence of P53 and K-ras alterations in ovarian mucinous and serous tumors

Clarification of the pathogenic relationships existing among ovarian cystadenomas, tumors of low malignant potential (LMP) and various adenocarcinoma types, a series of 29 mucinous and 19 serous ovarian tumors including adenomas, LMP tumors and adenocarcinomas were examined. P53 protein was detected by the streptavidin-biotin method and point mutation of K-ras codon 12 was detected by polymerase chain reaction-restriction fragment length polymorphism analysis. P53 overexpression was observed more frequently in serous adenocarcinomas (5/8, 63%) than in mucinous adenocarcinomas (2/9, 22%) and was correlated with the malignant potential of serous tumors. Furthermore, the proportion of P53-positive cells was significantly higher in serous adenocarcinomas than in mucinous adenocarcinomas. P53 overexpression may therefore be closely related to the early events of carcinogenesis in serous tumors. Although mutation of the K-ras oncogene appears to be an important event in the early tumorigenesis of mucinous tumors, mutation of the K-ras oncogene in serous tumors may be dependent on morphology. Different complex pathways of oncogene and/or tumor suppressor gene abnormalities may be involved in the development of mucinous and serous adenocarcinomas.     

BRAF Mutation Is Rare in Advanced-Stage Low-Grade Ovarian Serous Carcinomas

Low-grade ovarian serous carcinomas are believed to arise via an adenoma-serous borderline tumor-serous carcinoma sequence. In this study, we found that advanced-stage, low-grade ovarian serous carcinomas both with and without adjacent serous borderline tumor shared similar regions of loss of heterozygosity. We then analyzed 91 ovarian tumor samples for mutations in TP53, BRAF, and KRAS. TP53 mutations were not detected in any serous borderline tumors (n = 30) or low-grade serous carcinomas (n = 43) but were found in 73% of high-grade serous carcinomas (n = 18). BRAF (n = 9) or KRAS (n = 5) mutation was detected in 47% of serous borderline tumors, but among the low-grade serous carcinomas (39 stage III, 2 stage II, and 2 stage I), only one (2%) had a BRAF mutation and eight (19%) had a KRAS mutation. The low frequency of BRAF mutations in advanced-stage, low-grade serous carcinomas, which contrasts with previous findings, suggests that aggressive, low-grade serous carcinomas are more likely derived from serous borderline tumors without BRAF mutation. In addition, advanced-stage, low-grade carcinoma patients with BRAF or KRAS mutation have a better apparent clinical outcome. However, further investigation is needed.Serous carcinoma is the most common histological subtype of epithelial ovarian cancer. Recent evidence strongly suggests that a two-tier system stratifying serous carcinoma into low-grade and high-grade categories is biologically and clinically relevant.^1–12 Low-grade serous carcinomas are believed to arise via an adenoma–serous borderline tumor–carcinoma sequence, whereas high-grade serous carcinomas develop from an unknown precursor.^6,7 While previous reports indicate that low-grade serous carcinomas may develop from either recurrence of a serous borderline tumor or de novo, the mechanism associated with the former type of development is not fully understood.^13–15 Almost all serous borderline tumors that recur are associated with noninvasive or invasive peritoneal implants (stages II–IV) at initial diagnosis of the serous borderline tumor.^13–17According to the World Health Organization, the pattern of serous borderline tumors may be classified as either typical or micropapillary.^15,18–21 The micropapillary pattern was initially described in 1996; accounts for 8% to 18% of serous borderline tumors; and is associated with a greater frequency of bilaterality, a greater association with peritoneal implants (particularly invasive implants), and a higher risk of relapse than the typical pattern of serous borderline tumor.^15,18–21 For all serous borderline tumors, regardless of the pattern, the risk of relapsing as low-grade ovarian serous carcinoma increases over time.²²Mutation analysis could provide insight into how low-grade serous carcinoma develops. The initial report on BRAF and KRAS mutations in low-grade serous carcinomas, which were believed to be derived from serous borderline tumors with micropapillary pattern, indicated a rate of BRAF or KRAS mutation of 68%.²³ Similarly, in serous borderline tumors, a rate of BRAF or KRAS mutation of 61% was reported.²³ However, in invasive high-grade serous carcinomas, BRAF and KRAS mutations were not found.^23–25 Conversely, TP53 mutations are quite common in high-grade serous carcinomas but exceedingly rare in serous borderline tumors and low-grade serous carcinomas.²⁶ However, the correlation of BRAF/KRAS with patient outcome in low-grade ovarian serous carcinomas has not been explored. In this study, we investigated the BRAF and KRAS mutation status of advanced-stage low-grade serous carcinomas with and without a background of serous borderline tumor at initial diagnosis.     

Heterogeneous genetic alterations in ovarian mucinous tumors: application and usefulness of laser capture microdissection.

Histologic observation of ovarian mucinous tumors suggests that there is a multistep transition through the accumulation of genetic alterations. We analyzed loss of heterozygosity (LOH) and replication error (RER) on TP53 and D17S855 as well as K-ras point mutations of the heterogeneous histologic areas of the same tumor in 26 cases of ovarian mucinous tumor. The laser capture microdissection (LCM) technique has been applied to the study of K-ras point mutation in 10 cases. As for genetic alterations for LOH or RER on TP53 and D17S855, 2 (1 borderline tumor and 1 carcinoma) of 14 cases and 4 (1 borderline tumor and 3 carcinomas) of 12 cases, respectively, showed genetic heterogeneities in different histologic areas. Six (2 borderline tumors and 4 carcinomas) of 18 cases showed heterogeneity of K-ras point mutation in the different histologic areas of the same tumor, and 5 (1 cystadenoma with Brenner tumor component, 2 borderline tumors, and 2 carcinomas) of 10 cases showed heterogeneous K-ras mutation pattern in the same tumor when the LCM technique was used. Atypical areas tended to show K-ras point mutations frequently. Out of 3 cases of mixed mucinous cystadenoma and Brenner tumor, 1 case showed K-ras point mutation in the Brenner tumor area but not in the area of mucinous cystadenoma. These preliminary results suggest that a subset of ovarian mucinous tumors occur through multistep carcinogenesis and show that LCM is useful for molecular pathologic studies.     

High-degree tumor budding and podia-formation in sporadic colorectal carcinomas with K-ras gene mutations

In vitro ras activation enhances the epithelial-mesenchymal transition of colorectal carcinoma cells. But ras effects are known to be highly dependent on cell types and the tissue context. Therefore, this study was made to test the hypothesis that in clinical colorectal carcinoma specimens, aggressive invasion phenotypes, specifically tumor budding and podia formation, would correlate with K-ras gene mutations. In a series of 95 clinically sporadic primary colorectal carcinomas collected ad hoc, tumor budding and podia formation were counted using pan-cytokeratin immunohistochemistry, and K-ras gene mutations in codons 12 and 13 were determined. Consistent with the hypothesis, tumor budding and podia formation were observed to be significantly higher in the 32 (34.7%) of the tumors with K-ras gene mutations (29 mutations in codon 12, 3 in codon 13), and this correlation was observed independent of the patterns of invasion (expansive versus infiltrative). Microsatellite status, numbers of losses of heterozygosity, adenomatous polyposis coli and p53 gene mutations, and degree of promoter methylations (CIMP status) were not associated with K-ras gene mutations. Besides their effects on the tumor cell cycles, oncogenic K-ras gene mutations in colorectal carcinomas could be important for aggressive tumor invasion. This may be important in metastasizing disease and could provide a rationale for developing drugs that interrupt ras-signaling cascades.     

p73基因在卵巢上皮性肿瘤中的表达及甲基化研究

目的 探讨卵巢上皮性肿瘤中p73蛋白的表达和基因启动子的甲基化情况,并观察其与临床病理学特征的关系.方法 制备包括68例卵巢癌、37例卵巢交界性肿瘤和21例卵巢良性肿瘤的组织芯片,用免疫组织化学EnVision法检测上述组织中p73蛋白表达情况,用亚硫酸氧盐修饰后测序法检测13例新鲜卵巢癌组织及5例新鲜卵巢交界性肿瘤组织的p73基因启动子甲基化情况.结果 92.6％ (63/68)的卵巢癌表达p73,p73蛋白总体表达率均值为32％(p73表达率指p73阳性细胞数所占的百分比),其中浆液性癌( 26/26)的表达率均值为40％,高于其他组织类型的癌(P=0.006).按照卵巢癌发病模式区分,Ⅱ型卵巢癌p73表达率均值(40％)高于Ⅰ型卵巢癌(24％),P=0.010.卵巢癌中p73的表达与临床分期及组织学分级无相关性(均P＞0.05).卵巢交界性肿瘤组(30/37)和良性肿瘤组(12/21)p73的总体表达率均值分别为16％和15％,该两组肿瘤中浆液性肿瘤表达率均值均高于黏液性肿瘤(P-0.003,P=0.026).卵巢癌组的p73阳性表达率均值明显高于交界性肿瘤组和良性肿瘤组(均P ＜0.05),交界性肿瘤组与良性肿瘤组比较差异无统计学意义(P＞0.05).浆液性肿瘤( 49/53)中,卵巢癌组(26/26) p73阳性表达率均值明显高于交界性肿瘤组(12/14)和良性肿瘤组(11/13;P =0.024和P=0.002),而卵巢交界性肿瘤组和良性肿瘤组比较差异无统计学意义(P=0.428).黏液性肿瘤(15/27)中,卵巢癌组(6/7)p73阳性表达率均值高于良性肿瘤组( 1/8;p=0.032),而卵巢癌组与卵巢交界性肿瘤组(8/12)、交界性肿瘤组与良性肿瘤组比较,差异均无统计学意义(P=0.234和P=0.201).p73启动子的甲基化结果显示,13例卵巢癌有8例发生甲基化,但每例样本甲基化频率有所不同,总体甲基化频率均值为8.0％.5例交界性肿瘤有2例发生甲基化,总体甲基化频率均值为9.0％,两组比较差异无统计学意义(P＞0.05).卵巢癌组p73甲基化额率与组织类型、发病模式、组织学分级及临床分期均无相关性(均P＞0.05).结论 卵巢上皮性肿瘤多数表达p73,卵巢癌p73的表达率均值明显高于交界性肿瘤和良性肿瘤,浆液性肿瘤高于其他组织类型;p73蛋白表达率与p73基因甲基化程度不存在简单线性相关关系.     

β-Catenin Expression Pattern in Stage I and II Ovarian Carcinomas : Relationship with β-Catenin Gene Mutations, Clinicopathological Features, and Clinical Outcome

The immunohistochemical expression pattern of beta-catenin has been correlated with beta-catenin gene mutations, clinicopathological features, and disease outcome in 69 stage I and II ovarian carcinomas. beta-Catenin expression was localized in the nuclei, in addition to the cytoplasm and membrane, in 11 tumors (16%): nine endometrioid carcinomas with widespread nuclear expression and two serous carcinomas with focal nuclear expression. The remaining 58 carcinomas (84%) only had membranous beta-catenin expression. All but one of the endometrioid carcinomas with nuclear beta-catenin expression had considerable squamous metaplasia, and five of these cases had large areas of endometrioid tumor of low malignant potential. In addition, beta-catenin nuclear expression was observed in atypical epithelial cells in endometriotic glands adjacent to an endometrioid carcinoma. Sequencing was performed on 25 tumors and corresponding normal tissue: all 13 endometrioid tumors as well as 12 carcinomas of other histological types (four serous, two clear cell, two mucinous, and two mixed). There were oncogenic mutations in the phosphorylation sequence for GSK-3beta in exon 3 of the beta-catenin gene in seven endometrioid carcinomas with beta-catenin nuclear expression. Three mutations affected codon 32 (D32G, D32Y, and D32Y), one affected codon 33 (S33C), two affected codon 37 (S37C and S37F), and one affected codon 41 (T41A). No mutations were observed in the other 18 carcinomas analyzed, comprising two endometrioid and two serous carcinomas with beta-catenin nuclear expression, and 14 carcinomas of different histological types with only membranous expression. In the univariate and multivariate survival analyses, beta-catenin nuclear expression was selected as an indicator of good prognosis, because no patient whose tumor expressed beta-catenin in the nuclei showed relapses or died, in contrast to the 19 relapses and deaths among patients with tumors that only had beta-catenin membranous expression, including three of the four patients with endometrioid carcinomas. Oncogenic beta-catenin mutation is characteristic of a group of endometrioid carcinomas with a good prognosis, most of which originate from previous benign or borderline lesions. Endometrioid carcinomas with exclusively membranous expression of beta-catenin seem to represent a different subgroup of carcinomas that probably have a worse prognosis. In early-stage ovarian cancer, determination of the beta-catenin expression pattern could prove to be a useful marker for selecting low-risk patients.     

ras gene mutations in salivary gland tumors

OBJECTIVE: To assess the prevalence of activating mutations in K-ras and H-ras genes in salivary gland tumors with ductal or acinar differentiation and to evaluate their potential correlation with clinical parameters. DESIGN: Paraffin-embedded tissue samples of salivary gland carcinomas were investigated by the application of a direct sequence analysis procedure with automated DNA sequencing of polymerase chain reaction-amplified ras sequences. SETTING: Tertiary care teaching hospital. PATIENTS: Twenty-four patients with salivary gland carcinoma were surgically treated. Nine had adenocarcinoma, 1 had adenosquamous carcinoma, 11 had mucoepidermoid carcinoma, and 3 had acinic cell carcinoma. RESULTS: Point mutations were detected in 7 (29%) of the 24 carcinomas examined. The K-ras gene was mutated in only 2 samples (8%): a GGC-to-ATC mutation at codon 13 in an adenocarcinoma and a GGC-to-GTC transversion mutation at codon 13 in a mucoepidermoid carcinoma. Five (21%) harbored H-ras mutations: 4 contained a GGC-to-GTC transversion mutation at codon 12 and 1 had 2 distinct mutations, the same G-to-T at codon 12 as was shown in the other cases and a GGT-to-GGA heterozygous mutation at codon 13. All the H-ras mutations were in the group of mucoepidermoid carcinoma lesions (45%; 5/11). CONCLUSION: Our data suggest that K-ras gene alteration is probably not an important factor in the oncogenesis of human salivary gland tumors. However, mutational activation of the H-ras gene appears to play a role in the development and/or progression of salivary gland mucoepidermoid carcinomas.