p53 protein overexpression and K-rascodon 12 mutation in pancreatic ductal carcinoma: Correlation with histologic factors

The correlation of p53 protein overexpression and the K-ras codon 12 mutatlon wlth histologlc type, grade of cytologic atypla, depth of lnvasion and other histologlc prognostic factors was studied In paraffin sectlons from 43 ductectatic-and 70 solid-type pancreatic ductal carcinomas. Overexpression of p53 was found in 23.3% (10143) of ductectatic carcinomas (17.2% of intraductal and 35.7% of lnvaslve carclnomas) and in 61.4% (43/70) of solid carcinomas. In ductectatic cancers, p53 overexpression was detected In 14.8% (4/27) of carcinomas wlth lowgrade atypla (CAL), 50.0% (5110) of carcinomas wlth high-grade atypla (CAH) and in 16.7% (In) of mixed low- and hlgh-grade cancers. In the last group, expression was restricted to an area of CAH. In solld cancers, p53 overexpression did not dlffer by histologic type or grade. Overexpresslon of p53 and K-ras mutatlons did not correlate with histologlc prognostic factors (lymphatic, venous and perineural Invasion, and lymph node metastasls) in ductectatlc and solld cancers or depth of invasion of solld carclnomas. Our data suggest that p53 alteratlon occurs at an early intraductal stage of solld carcinoma, irrespectlve of cellular atypla, but Is low in ductectatic CAL and becomes hlgher In ductectatlc CAH. K-ras mutatlon, present In a high percentage of tumors of all groups and not correlating with the factors above, showed no changes In frequency with tumor progression.     

直肠癌K—ras基因突变和细胞动力学异常

采用扩增片段限制性长度多态性分析（Amp－RFLP）和流式细胞分析技术（FCM）对直肠癌切除标本、癌旁远端肉眼观察“正常”的肠组织及正常肠粘膜，结合病理资料，比较其细胞DNA倍体性、S期百分比和增殖指数，检测K－ras基因12位密码子点突变，结果表明：直肠癌是进展迅速的恶性肿瘤，细胞增殖活性异常升高；K－ras基因突变是伴随直肠癌的一种基因异常表现，癌旁组织出现基因水平的异常发生在组织形态学和细胞动力学改变之前，是癌变发生的早期行为。     

Genetic Alterations of Mixed Hyperplastic Adenomatous Polyps in the Colon and Rectum

Some mixed hyperplastic adenomatous polyps (MHAPs) contain dysplastic lesions or even carcinomas. These polyps are considered to be different from ordinary hyperplastic polyps and may have a preneoplastic potential. We investigated APC and K- ras mutations in MHAPs of the colon and rectum, and also in colorectal adenomas and hyperplastic polyps to identify molecular differences between MHAPs, adenomas and hyperplastic polyps, using direct sequencing of mutation cluster regions (MCR) in APC and K- ras . No APC mutations were identified in 12 MHAPs and 8 hyperplastic polyps, whereas 10 of 27 (37.0%) adenomas showed somatic mutations. K- ras mutations were identified in one of 12 (8.3%) MHAPs, one of 8 (12.5%) hyperplastic polyps, and 10 of 27 (37.0%) adenomas. p53 mutation was found in a carcinoma arising in an MHAP. Mutations other than APC mutations may play a role in the development of MHAPs.     

K-ras基因突变对Ⅲ期大肠癌术后辅助化疗疗效的预测意义

目的 探讨K-ras基因突变与接受术后辅助化疗的Ⅲ期大肠癌患者预后的关系.方法 收集2005年1月-2010年12月在我院接受手术治疗及术后辅助化疗的Ⅲ期大肠癌病例40例,采用PCR扩增和DNA测序技术检测K-ras第12、13位密码子的突变情况,分析患者临床病理特征、分子特征与生存规律的关系.结果 K-ras基因突变率为15％(6/40),性别、年龄、病灶部位、病理分级、病理类型、T分期、N分期与K-ras基因突变无相关性.截至2010年12月31日,34例(85％)出现复发转移,9例(22.5％)死亡,中位总生存期(overall survival,OS)48.460个月,中位无疾病生存期(disease-free survival,DFS) 11.992个月,1年、3年、5年生存率分别为97％、73％、51％.单因素分析显示K-ras野生组较突变组DFS显著延长(P＜0.001),而其余病理特征对DFS无明显影响;年龄(P=0.037)、病理分级(P=0.015)及1年内是否复发转移(P=0.010)是影响OS的预后因素,而其余病理特征及K-ras基因状态对OS无影响.COX多因素分析显示K-ras基因状态(P＜0.001)是DFS的独立预后因素;年龄(P=0.010)和1年内是否复发转移(P=0.006)是OS的独立预后因素.结论 对于接受手术治疗及以氟尿嘧啶为基础的术后辅助化疗Ⅲ期大肠癌患者,K-ras野生型患者的DFS优于突变型患者,提示K-ras基因可能是预测Ⅲ期大肠癌患者术后辅助化疗疗效的指标.     

结直肠癌 K-ras 基因突变检测及其意义

目的：研究结直肠癌中K-ras基因突变率及突变类型,探讨结直肠癌K-ras基因野生型及突变型与患者临床参数的关系;通过基因测序,指导临床靶向药物用药。方法随机选取哈尔滨医科大学附属第三医院结直肠外科2008年9月至2010年3月收治的100例结直肠癌患者组织标本通过手术室取材、组织标本DNA提取、逆转录PCR、凝胶电泳、胶回收、直接测序等技术筛选K-ras基因突变标本进行统计分析,从中得出突变率及突变类型。结果共筛选出了34例（34％）K-ras基因突变标本,其基因突变均发生在第一外显子的第12及第13密码子。结果表明：第一外显子的第12密码子GGT突变为GAT或GTT;第一外显子第13密码子由GGC突变为GGT。其中并未发现第二外显子第59及第61位发生突变,及第一外显子12位13位同时突变。结论 K-ras基因结直肠癌中约有34％发生突变。在K-ras基因突变类型与患者的病期、病理类型、肿瘤的浸润深度、发病部位等因素无关。     

应用锁核酸探针技术检测肿瘤样本中K—ras基因突变

目的应用锁核酸探针技术检测肿瘤样本中K—ras基因突变,探讨其诊断价值。方法结合锁核酸TaqMan探针与实时荧光PCR技术建立K一ras基因突变快速检测法,与传统聚合酶链反应一单链构象多态性分析法（PCR—SSCP）及测序结果进行比较,评价新方法的诊断价值。结果锁核酸探针PCR法可对肿瘤样本中K—ras基因突变进行有效检测,操作简便;可在104倍的野生型K—rag基因背景下检测出突变,灵敏度为0．1％,可检测突变基因最低限为10拷贝/mL,相对应传统方法,本方法可同时进行较大规模的样品检测,更快捷和灵敏。结论锁核酸探针实时荧光PCR法较PCR—SSCP法有明显优势,适用于大规模临床样本的K—ras基因突变检测,可作为肿瘤筛查和预后判断有效手段。     

大肠癌K-ras基因突变状况与VEGF-c、Ang-2相关性分析

目的:探讨大肠癌K-ras基因突变状况与VEGF-c,Ang-2在大肠癌中的表达及相关性。方法:采用基因测序法,S-P免疫组化法对80例大肠癌组织及15例正常组织进行K-ras基因测序及免疫组化染色。结果:大肠癌组织中K-ras基因突变发生率为27.5%,VEGF-c,Ang-2,表达率分别为48.75%和35.00%。统计学显示K-ras基因突变与VEGF-c表达呈正相关(r=0.624,P<0.05),与Ang-2表达无相关性。结论:肿瘤新生血管的形成是一种多因素多途径的相互协同过程,对K-ras基因突变患者寻找新的靶点以便控制肿瘤微血管形成,切断肿瘤转移途径具有重要意义。     

K-ras基因突变型晚期大肠癌患者一线化疗及靶向治疗疗效分析

目的 探讨K-ras基因突变型晚期大肠癌患者一线化疗及联合靶向治疗方案的疗效.方法 回顾性分析2008年1月-2013年12月本院收治的经病理确诊的55例K-ras基因突变型晚期大肠癌患者的临床及病理特征,并行疗效观察及生存分析.结果 随访至2013年12月31日,55例中45例（81.8％）死亡,中位总生存期为14.4个月,中位无进展生存期为5.7个月,1年生存率为66％.在客观缓解率方面,奥沙利铂组客观缓解率（objective response rate,ORR）（32％）较伊立替康组ORR（23.1％）高,伊立替康＋BEV组ORR（37.5％）较伊立替康组ORR（23.1％）高,但差异均无统计学意义;在疾病控制率方面,伊立替康＋BEV组治疗疾病控制率（disease control rate,DCR）（100％）较伊立替康组DCR（84.6％）高,但亦无统计学差异.结论 K-ras突变型患者使用以奥沙利铂为主的化疗方案更有利于客观缓解率的提高;化疗联合贝伐珠单抗对于K-ras突变型患者生存期的延长显示出一定作用.     

直接测序法检测结肠癌患者K-ras基因的灵敏度及其临床价值分析

目的 探讨结肠癌患者应用直接测序法测定K-ras 基因的灵敏度及其临床价值。方法 选取我院2016 年2 月~2017 年4 月收治的结肠癌患者80 例，随机分为研究组和对照组两组，研究组患者通过直接测序法、对照组患者通过sanger 测序法检测患者体内的K-ras 基因突变情况，分析K-ras 基因突变率与患者肿瘤大小、肿瘤部位、患者年龄等一般资料之间的相关性。结果 研究组患者测定K-ras 基因突变的灵敏度明显高于对照组（P<0.05），肿瘤直径在5 cm 以上患者的K-ras 基因突变率明显低于直径在5 cm 以下的患者（P<0.05）研究组检出率与患者肿瘤部位及分化程度、患者年龄等存在相关性。结论 应用直接测序法检测结肠癌患者K-ras 基因的突变情况具有较高的灵敏度，直接测序法的检出率与患者的肿瘤大小、肿瘤分化程度以及患者的年龄等存在较强的相关性，对于临床上结肠癌等恶性肿瘤疾病的诊断具有较强的应用价值，值得临床上广泛推荐使用。     

The proto-oncogene KRAS is targeted by miR-200c

The GTPase K-ras is involved in a variety of cellular processes such as differentiation, proliferation and survival. However, activating mutations, which frequently occur in many types of cancer, turn KRAS into one of the most prominent oncogenes. Likewise, miR-200c is a key player in tumorigenesis functioning as a molecular switch between an epithelial, non-migratory, chemosensitive and a mesenchymal, migratory, chemoresistant state. While it has been reported that KRAS is modulated by several tumor suppressor miRNAs, this is the first report on the regulation of KRAS by miR-200c, both playing a pivotal role in oncogenesis. We show that KRAS is a predicted target of miR-200c and that the protein expression of KRAS inversely correlates with the miR-200c expression in a panel of human breast cancer cell lines. KRAS was experimentally validated as a target of miR-200c by Western blot analyses and luciferase reporter assays. Furthermore, the inhibitory rffect of miR-200c-dependent KRAS silencing on proliferation and cell cycle was demonstrated in dfferent breast and lung cancer cell lines. Thereby, the particular role of KRAS was dissected from the role of all the other miR-200c targets by specific knockdown experiments using siRNA against KRAS. Cell lines harboring an activating KRAS mutation were similarly affected by miR-200c as well as by the siRNA against KRAS. However, in a cell line with wild-type KRAS only miR-200c was able to change proliferation and cell cycle. Our findings suggest that miR-200c is a potent inhibitor of tumor progression and therapy resistance, by regulating a multitude of oncogenic pathways including the RAS pathway. Thus, miR-200c may cause stronger anti-tumor efffects than a specific siRNA against KRAS, emphasizing the potential role of miR-200c as tumor suppressive miRNA