结直肠癌KRAS和BRAF基因突变分子病理流行病学研究

目的 探讨结直肠癌患者KRAS和BRAF基因突变、临床病理特征以及流行病因素的分子病理流行病学.方法 应用多重等位基因特异性PCR(ARMS-PCR)技术检测1997-12-01-2014-09-26中国医学科学院北京协和医学院肿瘤医院病理科确诊的945例结直肠癌患者KRAS和BRAF基因突变情况,分析性别、体质量指数...     

原发性肝癌中 KRAS 及 BRAF 基因突变及其临床意义

目的：检测原发性肝癌患者血浆中的 KRAS 与 BRAF 基因突变机率及特征,研究与疾病进展的相关性及对治疗的意义。方法：收集肝癌患者血液（51例）,观察组25例,为肝癌伴肝外转移患者;对照组26例,为病灶局限于肝脏的肝癌患者。所有的患者抽取外周血10ml,从血样中游离 DNA,采用人类 KRAS ／NRAS 基因突变联合检测试剂盒及人类 BRAF 基因 V600E 突变检测试剂盒分别对 KRAS 基因和 BRAF 基因突变进行检测,并分析基因突变机率及与其突变特征。结果：51例肝癌患者中,伴肝外转移患者 KRAS 基因突变率（24％,6／25）明显高于无肝外转移患者 KRAS 基因突变率（0％,0／26;P ＜0．05）;肝癌患者中 BRAF 基因突变率为0％（0／51）。结论：本研究表明肝癌患者 KRAS 基因会发生明显的突变,且肝癌伴肝外转移患者,KRAS基因突变频率明显增加。未检测出 BRAF 基因突变或 BRAF 基因突变率较低。     

结直肠癌组织中KRAS和BRAF基因突变与临床病理特征及预后的关系

目的:探讨结直肠癌组织中KRAS和BRAF基因突变与临床病理和预后的关系.方法:采用扩增阻滞突变系统(ARMS)方法对134例结直肠癌组织进行回顾性分析.结果:134例CRC组织中KRAS基因突变率49.3％(66/134),第2外显子突变率42.5％(57/134),其中12及13密码子突变率分别为35.1％(47/...     

结直肠锯齿状通路中DNA甲基化的改变

在世界范围内,结直肠癌(colorectal cancer,CRC)的发病率居恶性肿瘤的第3位,在我国CRC发病率逐年上升,已跃居常见恶性肿瘤的前5位,广东地区和香港地区数字已接近西方国家。据报道2007年10%～15%CRC来自锯齿状病变,而     

结直肠癌患者KRAS和BRAF基因突变检测及其临床意义

目的探讨结直肠癌患者组织中KRAS和BRAF基因突变情况,分析突变与临床病理特征的关系。方法应用荧光PCR-优化寡核苷酸探针法检测304例结直肠癌石蜡包埋标本中KRAS基因2号外显子的12和13密码子、BRAF基因的15号外显子的突变情况,分析KRAS和BRAF基因突变与临床病理特征的关系。结果 KRAS和BRAF基因在结直肠癌的突变率分别为38.8%(118/304)和4.3%(13/304)。KRAS基因突变阳性标本中12密码子的突变率为78.0%,其中p.G12D发生率最高,占总突变的45.3%;13密码子的突变率为22.0%。高年龄组(≥60岁)患者的KRAS基因突变率为47.2%(58/123),高于低年龄组(<60岁)的33.1%(60/181),差异有统计学意义(P<0.05)。转移性结直肠癌患者19例,其KRAS基因突变率为36.8%(7/19),与285例原发性结直肠癌患者的突变率(38.9%,111/285)差异无统计学意义(P>0.05)。BRAF基因在结肠、低分化、黏液腺癌患者中的突变率明显高于直肠、中或高分化和管状腺癌的患者。结论结直肠癌患者中KRAS基因突变的发生率较高,与年龄相关,而与性别、部位、病理类型和分化程度不相关。BRAF基因突变与肿瘤部位、病理类型和分化程度有关。原发性与转移性结直肠癌患者KRAS基因突变率无明显差异。     

原发小细胞肺癌中BRAF/KRAS以及PIK3CA突变的基因特征及临床特征

目的 在中国人群小细胞肺癌(SCLC)标本中检测BRAF/KRAS以及PIK3CA基因突变频率,分析这些基因突变的基因特征和临床特征。方法 2009-2014年共收集557例单纯SCLC患者组织样本。利用双脱氧测序法进行BRAF、KRAS、PIK3CA、NRAS、MEK1基因突变检测。χ²检验分析临床因素与基因突变的相关性,Kaplan-Meier法生存分析,Cox模型多因素预后分析。结果 在557例标本中检测到13例BRAF突变,突变类型包括V600E (n=5)、V600A (n=2)、V600M (n=1)、D594G (n=1)、G464E (n=1)、K601R (n=2)、S605N (n=1)。6例KRAS突变,突变类型包括G12C (n=3)、G12A (n=1)、G12D (n=1)、G13D (n=1)。4例PIK3CA突变,突变类型包括E545G (n=2)、H1047R (n=2)。另外1例NRAS突变(Q61R)和1例MEK1突变(D61Y)。这些突变基因与患者年龄、性别、吸烟状态、临床分期均无相关性。单因素生存分析结果显示基因突变组患者的生存时间比无此类突变者生存时间差,中位生存时间分别为(10.30±0.75)个月(95%CI为8.83~11.77个月)和(12.80±0.54)个月(95%CI为11.74~13.86)(P=0.011)。结论 在单纯SCLC中存在小比例的BRAF/KRAS、PIK3CA基因突变群体,这些基因突变与患者的临床特征无明显统计学相关性,但单因素生存分析显示与患者生存预后呈负相关。     

COLD-PCR-HRM 检测结直肠癌患者外周血KRAS基因突变

目的  评价COLD-PCR-HRM 检测结直肠癌患者外周血KRAS 基因突变的临床应用价值。方法  将已知突变型 KRAS 组织DNA 与野生型DNA 做系列稀释,突变DNA 所占比例分别为50%、25%、10%、5%、3%、2% 和 1%。分别应 用常规PCR-HRM 法和COLD-PCR-HRM 法对不同比例KRAS 突变DNA 样本进行检测,验证两种检测方法的灵敏度;同 时应用 COLD-PCR-HRM 法对 62 例外周血和肿瘤组织配对样本进行一致性验证。结果  PCR-HRM 法最低检测浓度为 3%; COLD-PCR-HRM 法最低检测浓度为1%,两种方法的检测灵敏度均明显高于直接测序法（P ＜ 0.05）。应用COLD-PCRHRM 法检测两种样本中KRAS 基因突变状态,其中血清样本中检测出13 例突变（突变率21.0%,13/62）,组织中检测出 12 例突变（突变率 19.4%,12/62）,两种标本同时存在突变的有 9 例,以组织中检测的 KRAS 状态为准,两者突变一致性 为 75.0%（9/12）。KRAS 基因突变在组织与外周血中存在一致性（κ=0.649;P ＜ 0.001）。结论  COLD-PCR 结合 HRM 明 显提高了 KRAS 突变检测灵敏度,为其应用于低丰度突变样本检测提供了有利条件。     

BRAF和EphB2在人结直肠锯齿状腺瘤中的表达及意义

目的:探讨鼠类肉瘤滤过性病毒致癌基因同源体B1(v-raf murine sarcoma viral oncogene homolog B1,BRAF)和生促红素人肝细胞蛋白(erythropoietin-producing hepatoma cell line B2,EphB2)在人结直肠锯齿状腺瘤中的表达及其意义。方法:收集滨州医学院附属医院1996年1月至2008年5月10例正常结直肠肠黏膜、21例增生性息肉、22例锯齿状腺瘤、55例腺瘤性息肉(18例管状腺瘤、16例管状绒毛状腺瘤、21例绒毛状腺瘤)石蜡标本。免疫组织化学法检测BRAF和EphB2蛋白的表达量,同时观察蛋白的表达部位。结果:增生性息肉中BRAF蛋白阳性细胞多位于隐窝中下区域,腺瘤性息肉的阳性细胞多表达位于隐窝上部区域,而锯齿状腺瘤阳性细胞多表达于隐窝全层。锯齿状腺瘤与腺瘤性息肉的BRAF蛋白表达量相近[(0.129±0.030)vs(0.130±0.026),P>0.05],但远高于增生性息肉[(0.129±0.030)vs(0.102±0.014),P<0.01];锯齿状腺瘤、管状腺瘤、管状绒毛状腺瘤、绒毛状腺瘤之间BRAF蛋白表达量差异无统计学意义[(0.129±0.030)vs(0.116±0.019),(0.119±0.037),(0.122±0.008),P>0.05]。增生性息肉中EphB2蛋白阳性细胞多位于隐窝中下区域细胞膜上,腺瘤性息肉EphB2蛋白阳性细胞位于隐窝上部,而锯齿状腺瘤EphB2蛋白阳性细胞表达于隐窝全层。锯齿状腺瘤与腺瘤性息肉的EphB2蛋白表达量相近[(0.138±0.024)vs(0.139±0.025),P>0.05],而远高于增生性息肉[(0.138±0.024)vs(0.169±0.018),P<0.01];锯齿状腺瘤与管状腺瘤、管状绒毛状腺瘤、绒毛状腺瘤间EphB2蛋白表达量无区别[(0.138±0.024)vs(0.143±0.027),(0.139±0.028),(0.133±0.021),P>0.05]。结论:BRAF和EphB2蛋白在增生性息肉、腺瘤性息肉中隐窝部分区域表达,而在锯齿状腺瘤中隐窝全层表达,提示锯齿状腺瘤是一类独立的不同于腺瘤性息肉的结直肠肿瘤。     

结直肠锯齿状病变病理诊断及鉴别诊断

结直肠癌是最常见及致死率最高的癌症之一,其发生机制有两个主要通路:即经典的“腺瘤-腺癌”通路和锯齿状通路。锯齿状通路因其独特的分子病理学改变,而被认为是独立于经典的“腺瘤-腺癌”通路之外的结直肠癌发生路径。Longacre和Fenoglia Preiser于1990年对大肠“混合性增生性腺瘤样息肉”(mixed hyperplastic adenomatous polyps,MHAP)进行重新评估,并首次使用“锯齿状腺瘤”(serrated adenoma,SA)来定义此类病变。锯齿状病变的组织学分类及致癌的分子机制已部分阐明。然而,在实际工作中,病理医生,特别是年轻的病理医生对锯齿状病变分类及诊断仍存困惑。本文拟就锯齿状病变的分类、临床病理学特征、诊断及鉴别诊断要点进行讨论。     

BRAF and KRAS mutations in prostatic adenocarcinoma

Constitutive activation of the kinase cascade involving RAS, RAF, MEK and ERK is common to human cancers, and mutations of KRAS and BRAF are mutually exclusive and serve as alternatives to activate the RAS/RAF/ERK signaling pathway. RAS mutations are known to occur in prostate adenocarcinomas, but little is known about BRAF mutations in these tumors. In the present study, BRAF and KRAS mutations were characterized in 206 prostate adenocarcinomas by enhanced PCR-RFLP and direct sequencing. The identified KRAS and BRAF mutations were then analyzed with respect to preoperative serum PSA levels, Gleason scores and tumor stages. Mutations in codon 600 of BRAF were identified in 21 (10.2%) of 206 prostate adenocarcinomas. KRAS mutations in codons 12 or 13 were found in 15 (7.3%) of 206 prostate adenocarcinomas. However, no tumor specimen contained both BRAF and KRAS mutations. Prostate adenocarcinomas with a BRAF mutation tended to show higher preoperative serum PSA levels, Gleason scores and tumor stages than prostate adenocarcinomas with a KRAS mutation. The results obtained show that BRAF mutations are as uncommon as KRAS mutations in prostate adenocarcinoma. Although BRAF and KRAS are members of the same RAS/ERK signaling pathway, prostate adenocarcinomas with a BRAF mutation showed clinicopathologic features that differed from those of prostate adenocarcinoma with a KRAS mutation.     

Mutation Analysis of KRAS and BRAF Genes in Metastatic Colorectal Cancer: a First Large Scale Study from Iran

Background: The investigation of mutation patterns in oncogenes potentially can make available a reliable mechanism for management and treatment decisions for patients with colorectal cancer (CRC). This study concerns the rate of KRAS and BRAF genes mutations in Iranian metastatic colorectal cancer (mCRC) patients, as well as associations of genotypes with clinicopathological features. Materials and Methods: A total of 1,000 mCRC specimens collected from 2008 to 2012 that referred to the Mehr Hospital and Partolab center, Tehran, Iran enrolled in this cross sectional study. Using HRM, Dxs Therascreen and Pyrosequencing methods, we analyzed the mutational status of KRAS and BRAF genes in these. Results: KRAS mutations were present in 33.6% cases (n=336). Of KRAS mutation positive cases, 85.1% were in codon 12 and 14.9% were in codon 13. The most frequent mutation at KRAS codon 12 was Gly12Asp; BRAF mutations were not found in any mCRC patients (n=242). In addition, we observed a strong correlation of KRAS mutations with some clinicopathological characteristics. Conclusions: KRAS mutations are frequent in mCRCs while presence of BRAF mutations in these patients is rare. Moreover, associations of KRAS genotypes with non mucinous adenocarcinoma and depth of invasion (pT3) were remarkable.     

Wild-type KRAS and BRAF could predict response to Cetuximab in Chinese colorectal cancer patients

Objective  

To analyze the relationship between KRAS, BRAF mutations and the response to Cetuximab in Chinese colorectal cancer patients.     

BRAF,KRAS and PIK3CA Mutation and Sensitivity to Trastuzumab in Breast Cancer Cell Line Model

Studies show that approximately 20% of all breast cancer patients have a breast tumor that tests positive for Human Epidermal Growth Factor Receptor 2, otherwise known as the HER2 gene. As such, treatments for breast cancer usually include drugs that target HER2. The drug Trastuzumab is a recombinant antibody that has been approved by the FDA for the treatment of these HER2 positive breast cancers. However, researchers have found that mutations in associated genes, PIK3CA and KRAS, can cause the tumor to become resistant to Trastuzumab. The purpose of this article is to evaluate the sensitivity of the cancer cell lines to the drug Trastuzumab and investigate how this sensitivity is compromised by the PIK3CA, KRAS and BRAF gene mutations. Trastuzumab responsiveness was evaluated in breast cancer cell lines by treating the lines with an optimal concentration of the drug followed by a proliferation assay of the cell lines in the presence of monoclonal antibodies. We determined the optimum concentration of Trastuzumab to be 7 μg/well. The BRAF and KRAS mutated cell line, MDA-MB-231, showed the least sensitivity after being treated with trastuzumab when compared to the sensitivity of the PIK3CA mutated cell lines, MCF-7 and MDA-MB-361, and the KRAS/ BRAF/ PIK3CA cell line, MDA-MB-453. Clinical observations show that mutations in BRAF and KRAS genes in breast cancer cells do lower the responsiveness of Trastuzumab drug treatments.     

Value of KRAS,BRAF, and PIK3CA Mutations and Survival Benefit from Systemic Chemotherapy in Colorectal Peritoneal Carcinomatosis

Background: It is well known that peritoneal carcinomatosis (PC) from colorectal cancer (CRC) is associated with a poor prognosis. However, data on the prognostic significance of modern chemotherapy containing bevacizumab, cetuximab or panitumumab are not available. Materials and Methods: This retrospective review concerned 526 patients with metastatic CRC who were classified into two groups according to the presence or absence of PC, and were treated with systemic chemotherapy, with or without bevacizumab or anti-EGFR antibodies. The genetic background, in particular KRAS, BRAF, and PIK3CA gene mutations, and overall survival (OS) were compared between the two groups. Results: The median OS values were 23.3 and 29.1 months for PC and non-PC patients, respectively (hazard ratio [HR]=1.20; p=0.17). Among all patients, tumor location, number of metastatic sites and BRAF mutation status were significant prognostic factors, whereas the presence of PC was not. In the PC group, chemotherapy with bevacizumab resulted in a significantly longer OS than forchemotherapy without bevacizumab (HR=0.38, p<0.01), but this was not the case in the non-PC group (HR=0.80, p=0.10). Furthermore, the incidence of the BRAF V600E mutation was significantly higher in PC than in non-PC patients (27.7% versus 7.3%, p<0.01). BRAF mutations displayed a strong correlation with shorter OS in non-PC (HR=2.26), but not PC patients (HR=1.04). Conclusions: Systemic chemotherapy, especially when combined with bevacizumab, improved survival in patients with PC from CRC as well as non-PC patients. While BRAF mutation demonstrated a high frequency in PC patients, but it was not associated with prognosis.