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。     

云南地区结直肠癌患者RAS/BRAF/PIK3CA基因突变状态及与临床病理特征的关系

目的:本研究主要对结直肠癌患者的KRAS/NRAS/BRAF V600E/PIK3CA基因突变情况及与临床病理特征的关系进行探究。方法:我们对2018年01月至2020年01月在我院分子诊断中心进行基因检测的结直肠癌患者的KRAS/NRAS/BRAF V600E/PIK3CA突变情况进行回顾性分析,共纳入209例具有完整临床信息的患者,所有患者的基因检测都是采用高通量测序方法获得的,并对患者的人口统计学和临床信息进行分析。结果:209例结直肠癌患者中,KRAS、NRAS、BRAF V600E、PIK3CA突变例数分别为98例、7例、10例和25例,突变率分别为46.9%、3.3%、4.8%和12.0%。KRAS 2号外显子突变最常见,其中又以G12D亚型突变高发,肿瘤原发部位在直肠的患者和微卫星稳定的CRC患者KRAS突变率明显高于原发部位在左右半结肠和微卫星不稳定的患者(P<0.05);BRAF V600E在MSI-H的CRC患者中突变率显著高于MSS的患者(P<0.05);男性患者、既往没有吸烟史、有淋巴结转移、临床分期较早以及MSI-H的CRC患者有更高的PIK3CA...     

KRAS、BRAF基因突变在大肠锯齿状病变中的临床应用

目的研究KRAS、BRAF基因突变在大肠锯齿状病变中的临床应用。方法选取100例大肠锯齿状病例经切除术后的石蜡标本进行研究。应用直接测序技术对KRAS、BRAF基因的突变进行检测分析。结果大肠锯齿状病变中KRAS基因突变率为40.00%,BRAF基因突变率为6.67%。所有大肠锯齿状病变患者中有40例检出KRAS基因突变,突变率为40.00%,其中KRAS基因12、13密码子突变率分别为30.00%以及10.00%。KRAS基因突变率与患者性别、年龄、病变部位、分化程度以及淋巴结转移等临床病理特征均无关(P>0.05)。BRAF基因突变在>65岁患者以及大肠近端情况较多见(P<0.05)。结论随着KRAS、BRAF基因突变的研究不断深入,对指导临床进行随访及药物治疗预后的判定具有重要的临床意义。     

江苏地区肺癌和胃癌患者 KRAS 基因突变状态分析*

目的:检测江苏地区肺癌和胃癌患者KRAS基因突变状态及其与临床病理特征的关系,并比较其在两种癌症间的异同。方法:收集肺癌128 例,胃癌115 例。采用直接测序法检测KRAS基因第2 号外显子突变,分析基因突变状态及其与临床病理特征的相关性。结果:KRAS基因突变率在肺癌和胃癌中无显著性差异（6.3% vs. 4.3% ,P > 0.05）。 两种癌症中,KRAS 基因突变都以第12密码子为主。KRAS 突变与年龄,性别无明显相关。肺腺癌患者KRAS基因突变高于非腺癌包括鳞癌等（10.7% vs. 0 ,P < 0.05）。 结论:江苏地区肺癌和胃癌患者中,KRAS第2 外显子突变率均较低,男性和女性的突变率无明显差异。肺腺癌患者KRAS基因突变率相对较高,因此个体化治疗前应同时检测KRAS 基因,以筛选出对靶向治疗耐药的肺癌患者,从而更好地指导患者的个体化分子靶向治疗。      

结直肠癌Ras、BRAF和PIK3CA基因突变分析及与临床病理特征的关系

目的 分析结直肠癌患者中Ras（K-Ras／N-Ras）、BRAF和PIK3CA基因突变情况及其与临床病理特征的关系。方法 回顾性分析2013年12月至2014年10月于北京大学肿瘤医院消化肿瘤内科接受诊治的200例结直肠癌患者的肿瘤组织标本,采用PCR扩增-直接测序法检测Ras,包括K-Ras（第2、3、4外显子）、N-Ras（第2、3、4外显子）、BRAF（第15外显子）及PIK3CA（第9、20外显子）基因的突变状态,分析其与结直肠癌临床病理特征的关系。结果 200例患者中存在Ras基因突变92例（46.0％）,其中K-Ras基因突变87例（43.5％）,主要发生在外显子2,N-Ras基因突变5例（2.5％）;其中1例患者存在K-Ras、N-Ras基因同时突变。存在BRAF基因突变15例（7.5％）,突变类型均为V600E,且与K-Ras突变存在排他性。存在PIK3CA基因突变9例（4.5％）,可与Ras或BRAF基因突变共存。Ras（K-Ras／N-Ras）基因在年龄≥65岁患者中的突变率明显高于＜65岁者（P＜0.05）,其表达与性别、原发部位、组织学类型、分化程度、TNM分期、区域淋巴结转移、远处转移、术后复发转移均无关（P均＞0.05）。BRAF、PIK3CA基因在原发部位为右半结肠患者中的突变率明显升高（P＜0.05）,但与年龄、性别、组织学类型、分化程度、TNM分期、区域淋巴结转移、远处转移、术后复发转移均无关（P＞0.05）。结论 N-Ras、PIK3CA基因在中国结直肠癌患者中的突变率较低。K-Ras、N-Ras基因突变与年龄相关,BRAF、PIK3CA基因与肿瘤原发部位相关;对结直肠癌患者进行Ras（K-Ras／N-Ras）、BRAF及PIK3CA基因的联合检测将会为提高临床靶向治疗的疗效提供更加可靠的依据。     

肺腺癌患者EGFR和KRAS基因突变与预后的相关性研究

目的 探讨肺腺癌患者表皮生长因子受体(EGFR)和KRAS基因突变与预后的相关性.方法 选取134例肺腺癌患者的肺腺癌组织标本,应用探针扩增阻滞突变系统在PCR仪上进行EGFR和KRAS基因突变检测,分析EGFR和KRAS基因突变与肺腺癌患者临床病理特征及预后的关系.结果 134例患者中,EGFR基因突变53例,突变率为39.55%,KRAS基因突变6例,突变率为4.48%.肺腺癌患者EGFR基因突变率与年龄、吸烟史有关(P﹤0.01).EGFR基因突变型患者的KRAS基因突变率低于EGFR基因野生型患者(P﹤0.05).EGFR基因突变型患者的无进展生存期(PFS)长于EGFR基因野生型患者(P﹤0.05),KRAS基因野生型患者的PFS长于KRAS基因突变型患者(P﹤0.05).结论 EGFR基因突变的肺腺癌患者KRAS基因更倾向于野生型,EGFR基因突变型或KRAS基因野生型的肺腺癌患者PFS更长.     

BRAF V600E突变与甲状腺乳头状癌临床病理特征的相关性

目的:探讨BRAF V600E基因突变对甲状腺乳头状癌（PTC）临床病理特征的影响。方法:收集经甲状腺切除术且病理证实为PTC患者的临床资料,分析BRAF V600E基因突变与PTC临床病理特征、甲状腺功能的关系。结果:PTC患者882例,发生BRAF V600E基因突变者722例（81.86%）,单因素分析显示,突变组癌灶多发、双侧、包膜外侵犯比例、复发危险度分层中/高危及TNM分期Ⅲ/Ⅳ期明显高于未突变组,差异均有统计学意义（均P＜0.05）;而淋巴结转移率、转移数目和直径均无统计学差异;突变组TPOAb、TGAb、TSH水平低于未突变组,差异均有统计学意义（均P＜0.05）,FT4、FT3水平无统计学差异（均P＞0.05）。分别行多因素Logistic回归分析显示:BRAF V600E基因突变与癌灶多发、包膜外侵犯显著相关（OR值分别为1.722、1.436,均P＜0.05）;原发癌灶直径>1 cm、BRAF基因突变、TGAb异常升高与PTC患者包膜外侵犯呈独立正相关（OR值分别为2.862、1.619、1.532,均P＜0.05）。结论:BRAF V600E基因突变的PTC易发多灶和包膜外侵犯,提示可能有不良预后;癌灶直径>1 cm、BRAF V600E基因突变及TGAb异常升高是PTC包膜外侵犯的独立危险因素。     

430例中国非小细胞肺癌患者EGFR、KRAS、BRAF和PIK3CA基因突变状态及其临床意义

目的： 探讨非小细胞肺癌（non-small cell lung cancers,NSCLC）患者表皮生长因子受体（epidermal growth factor receptor, EGFR）信号通路中EGFR、Kirsten鼠肉瘤病毒癌基因(Kirsten rat sarcoma viral oncogene homolog, KRAS)、B-Raf原癌基因丝氨酸/苏氨酸蛋白激酶(B-Raf proto oncogene serine/threonine protein kinase,BRAF)和磷脂酰肌醇-3-激酶α亚单位(phosphatidylinositol -4,5- bisphosphate 3-kinase catalytic subunit alpha,PI3KCA)基因的突变状态及其临床意义,为酪氨酸酶抑制剂（tyrasin kimase inhibitor, TKI)临床用药与科学研究提供依据。方法：采用SurPlex-xTAG70plex液相芯片技术平台检测中国430例NSCLC患者的福尔马林固定石蜡包埋(formalin fixed paraffin embedded, FFPE)组织中EGFR、KRAS、BRAF和PIK3CA基因的突变状态,分析基因的突变率及其与临床病理特征的关系。结果： EGFR、KRAS、BRAF和PIK3CA的突变率分别为41.2%,79%,0.7%和3.7%。EGFR外显子19、21在女性患者中的突变率明显高于男性（P<0.01）, 在肺腺癌患者中的突变率明显高于其他类型肺癌（P<0.01）,在无吸烟史患者中的突变率高于有吸烟史的患者（P<0.01）。相反地,KRAS突变在男性患者中的突变率高于女性（P<0.05）,在肺腺癌中的突变率高于肺鳞癌（P<0.005）,有吸烟史患者的突变率高于无吸烟史患者（P<0.01）。在肺腺癌患者中PIK3CA的突变率明显低于其他类型肺癌（P<0.01）。结论： EGFR和KRAS基因突变率与性别、组织学类型及吸烟史密切相关。在检测中发现EGFR和KRAS双突变,此外PIK3CA突变并非与EGFR和KRAS突变互斥。     

非小细胞肺癌EGFR、KRAS基因突变与RRM1、TUBB3 mRNA表达水平的相关性

目的:探讨非小细胞肺癌（NSCLC）EGFR、KRAS基因突变与核苷酸还原酶亚基M1（RRM1）、Ⅲ型β微管蛋白（TUBB3）mRNA表达水平的相关性及其临床意义。方法:69例NSCLC组织标本来自解放军空军总医院胸外科2010年6月至2014年10月手术中从肿瘤中心切取。使用xTAG-液相芯片法检测EGFR、KRAS基因突变,分支DNA-液相芯片法检测RRM1、TUBB3 mRNA表达水平。结果:在69例NSCLC组织样本中,28例为EGFR基因突变（40.6%,28/69）,13例为KRAS基因突变（18.8%,13/69）,EGFR基因突变与性别（P=0.005）、病理类型（P=0.036）、吸烟史（P=0.029）相关。KRAS基因突变与性别相关（P=0.007）。TUBB3 mRNA的表达水平与病理类型相关（P=0.008）,RRM1 mRNA的表达水平与患者各临床病理特征无关（P＞0.05）。EGFR基因突变与RRM1、TUBB3 mRNA表达水平无关（P＞0.05）,KRAS基因突变与RRM1 mRNA表达水平无关（P＞0.05）,KRAS突变型患者TUBB3 mRNA表达水平比KRAS野生型患者高（P＜0.05）。结论:在NSCLC患者中,EGFR及KRAS基因的突变状态对评估患者使用吉西他滨及抗微管类药物的疗效有重要意义,尤其在KRAS突变型NSCLC患者中,抗微管类化疗药物的疗效可能不佳,这有利于指导化疗药物方案的制定,促进NSCLC的个体化治疗。     

贝伐珠单抗联合化疗治疗KRAS突变型晚期左、右半结肠癌疗效的对比分析

目的:对比分析姑息一线应用贝伐珠单抗联合化疗治疗KRAS突变型晚期左、右半结肠癌的临床疗效。方法:回顾性分析我院于2016年09月至2020年09月收治的83例一线应用贝伐珠单抗联合化疗治疗KRAS突变型晚期左、右半结肠癌患者,比较KRAS突变型左、右半结肠癌患者的临床特征、客观缓解率（ORR）、疾病控制率（DCR）、无进展生存时间（PFS）、18个月生存率、总生存时间（OS）。结果:KRAS突变型晚期右半结肠癌（RSCC）患者合并不完全肠梗阻及体重减轻＞5 kg所占比例更高（P=0.369、P=0.009）,KRAS突变型晚期左半结肠癌（LSCRC）患者更易合并中重度以上的贫血（P=0.154）。KRAS突变型LSCRC患者发生腹腔种植转移及远处器官转移的患者比例高于RSCC患者（P＞0.05）。KRAS突变型LSCRC患者与RSCC患者ORR分别为29.3%和28.6%（P=0.944）,DCR分别为87.8%和90.5%（P=0.696）。18个月生存率LSCRC组为80.05%,RSCC组为76.2%,差异无统计学意义（P=0.635）。KRAS突变型LSCRC患者中位 PFS差于RSCC患者（8个月 vs 9.8个月,P=0.004）,KRAS突变型LSCRC患者中位OS优于KRAS突变型RSCC患者中位OS（22.8个月 vs 21个月,P=0.001）。结论:姑息一线应用贝伐珠单抗联合化疗治疗KRAS基因突变型mCRC患者,左、右半结肠癌的远期疗效存在差异。     

Clinical Significance of Somatic Mutations in RAS/RAF/MAPK Signaling Pathway in Moroccan and North African Colorectal Cancer Patients

Background: Mutations in RAS (KRAS, NRAS) and BRAF genes are the main biomarker predicting response to anti-EGFR monoclonal antibodies in targeted therapy in colorectal cancer (CRC). Objective: Our study aims to evaluate the frequencies of KRAS, NRAS and BRAF mutations and their possible associations with clinico-pathological features in CRC patients from Morocco. Methods: DNA was extracted from 80 FFPE samples using the QIAamp DNA FFPE-kit. RAS and BRAF mutations were assessed by pyrosequencing assays using Qiagen, KRAS Pyro®kit 24.V1, Ras-Extension Pyro®kit 24.V1 and BRAF Pyro®Kit 24.V1, respectively, and carried out in the PyroMark-Q24. Results: RAS mutations were identified in 57.5% (56.2% in KRAS, 8.8% in NRAS). In KRAS gene, exon 2 mutations accounted for 93.3% (68.9% in codon 12, 24.4% in codon 13). Within codon 12, G12D was the most prevalent mutation (37.7%), followed by G12C (13.4%), G12S (8.9%) and G12V (6.6%). Within codon 13, the most frequently observed mutation was G13D (22.3%). The mutation rates of exon 3 and 4 were 15.6% and 13.3%, respectively. In exon 3 codon 61, 2.3% patients were detected with two concurrent mutations (Q61R, Q61H), and 4.4% with three concurrent mutations (Q61R, Q61H, Q61L). In NRAS gene, the mutation rates of exon 2, 3 and 4 were 57.1%, 28.6%, and 14.3%, respectively. G13A and Q61H were the most common mutations, accounting for 42.9% and 28.5%, respectively. There were 13% patients with concurrent KRAS/NRAS mutation and 4.3% wt KRAS with NRAS mutations. No mutations were identified in BRAF gene. In both sexes, KRAS codon 12 mutations were associated with higher stage III/IV tumors. Moreover, Patients whose tumor is in the proximal colon (56.3%) are more likely to harbor KRAS mutations than those tumor located in rectum (25%). Conclusion: RAS mutations could be useful in future target anti-EGFR therapy and molecular CRC screening strategy in Morocco.     

Distribution of KRAS and BRAF Mutations in Metastatic Colorectal Cancers in Turkish Patients

The results of this study demonstrate the potential prognostic and predictive values of KRAS and BRAF gene mutations in patients with colorectal cancer (CRC). It has been proven that KRAS and BRAF mutations are predictive biomarkers for resistance to anti-EGFR monoclonal antibody treatment in patients with metastatic CRC (mCRC). We demonstrated the distribution of KRAS (codons 12, 13 and 61) and BRAF (codon 600) gene mutations in 50 mCRCs using direct sequencing and compared the results with clinicopathological data. KRAS and BRAF mutations were identified in 15 (30%) and 1 (2%) patients, respectively. We identified KRAS mutations in codon 12, 13 and 61 in 73.3% (11/15), 20% (3/15) and 6.67% (1/15) of the positive patients, respectively. The KRAS mutation frequency was significantly higher in tumors located in the ascending colon (p=0.043). Thus, we found that approximately 1/3 of the patients with mCRC had KRAS mutations and the only clinicopathological factor related to this mutation was tumor location. Future studies with larger patient groups should yield more accurate data regarding the molecular mechanism of CRC and the association between KRAS and BRAF mutations and clinicopathological features.     

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。     

BRAF mutation, CpG island methylator phenotype and microsatellite instability occur more frequently and concordantly in mucinous than non-mucinous colorectal cancer

Mucinous colorectal cancer (CRC) has been reported to have distinct clinicopathological and genetic characteristics. However, the incidence and the relationship among microsatellite instability (MSI), CpG island methylator phenotype (CIMP) and BRAF and KRAS mutations in mucinous and non-mucinous CRC are not known. Activating mutations of BRAF and KRAS and their relationship with MSI and CIMP were examined in 83 sporadic CRC specimens (26 mucinous and 57 non-mucinous CRC). MSI, CIMP, BRAF and KRAS mutation were observed in 17, 24, 25 and 36% of the tumors, respectively. BRAF mutation was highly correlated with MSI (p < 0.001) and CIMP (p < 0.001). A higher incidence of MSI (27% vs. 12%), CIMP (38% vs. 18%, p < 0.05) and BRAF mutation (46% vs. 16%, p < 0.01) was observed in mucinous CRC. KRAS mutation (27% vs. 40%) was observed more frequently in non-mucinous CRC. Significantly higher percentages of mucinous CRC (54%, p < 0.05) had MSI or CIMP or BRAF mutations. Concordant occurrence of 2 or more of these alterations was observed in 39% of mucinous CRC and only 11% of non-mucinous CRC (p < 0.01). The more frequent occurrence and closer association among MSI, CIMP and BRAF mutation in mucinous CRC observed in our study further supports the idea that its pathogenesis may involve distinct genetic and epigenetic changes.     

Mutation analysis of the BRAF, ARAF and RAF-1 genes in human colorectal adenocarcinomas

Colorectal cancer is a multi-step process characterized by a sequence of genetic alterations in cell growth regulatory genes, such as the adenomatous polyposis coli, KRAS, p53 and DCC genes. In the present study mutation analysis was performed with SSCA/direct sequencing of the hot-spot regions in exons 11 and 15 for the BRAF gene and exons 1-2 for the KRAS gene in 130 primary colorectal cancer tumors and correlated with clinico-pathological and mutational data. We also performed mutation analysis of the corresponding conserved regions in the ARAF and RAF-1 genes. Mutations in the BRAF and KRAS genes were found in 11.5 and 40% of the tumors, respectively. One germline exonic and nine germline intronic genetic variants were found in the ARAF and RAF-1 genes. All of the BRAF mutations were located in the kinase domain of the conserved region 3 in exon 15 of the BRAF gene. One novel somatic mutation was also identified in the BRAF gene. The majority of the BRAF mutations were found in colon compared with rectal tumors (P = 0.014). In agreement with others, a statistically significant correlation between BRAF mutations and microsatellite instability could be found. A negative correlation was also evident between mutations in the BRAF and KRAS genes, which supports earlier studies where somatic mutations in these genes are mutually exclusive. Collectively, our results provide support for the idea that activation of the MAP kinase pathway, especially via BRAF and KRAS mutations, is of critical importance for the development of colorectal cancer.     

皮肤黑色素瘤基因突变类型及基因拷贝数变异分析

  目的  对比肢端黑色素瘤（acral melanoma, AM）与非肢端黑色素瘤（non-acral melanoma, NAM）的基因突变类型及基因拷贝数变异（copy number variation, CNV）的差异,讨论并分析其基因突变类型及拷贝数变异的意义。  方法  收集2018年1月至2021年1月新疆医科大学附属肿瘤医院收治的73例皮肤黑色素瘤患者的资料,所有患者均采用二代测序技术对46个癌症相关基因进行了全面的基因组检测。根据解剖部位分为肢端组（AMs）和非肢端组（NAMs）,比较并讨论两组患者的临床病理特征、基因突变类型及CNV的差异。  结果  两组患者在性别、年龄、肿瘤厚度、溃疡、淋巴结状态和分期等方面无显著性差异（P>0.05）。73例患者最常见的基因突变类型为BRAF突变（20.5%）、KRAS/NRAS突变（17.8%）、KIT突变（13.7%）。与AMs相比,NAMs的BRAF突变频率呈显著性差异（P<0.05）。年龄≤65岁的患者BRAF突变率与年龄>65岁的患者相比呈显著性差异（P<0.05）。此外,无溃疡的黑色素瘤比有溃疡的黑色素瘤更易出现BRAF突变（P<0.05）。两组患者中KRAS/NRAS和KIT突变率无显著性差异（P>0.05）。影响细胞周期畸变基因（CDK4/6、CCND1/2、CDKN2A）、受体酪氨酸激酶基因（EGFR、MET、ERBB2、ERBB3、PDGFRA）及抗细胞凋亡基因（BIRC2/3/5）的CNV在AMs和NAMs之间呈显著性差异（P=0.019、0.002、0.027）。  结论  通过对AMs和NAMs基因突变类型及CNV的分析,能为深入了解皮肤恶性黑色素瘤致癌模式和临床病理特征提供帮助。      

KRAS, BRAF and PIK3CA mutations in human colorectal cancer: relationship with metastatic colorectal cancer

Many abnormal gene expressions and dysregulated signaling pathways have been found in human colorectal cancer. Activating mutations of the KRAS, BRAF or PIK3CA oncogenes are frequently found in colorectal cancer. The aim of the study was to investigate the molecular occurrence of KRAS, BRAF and PIK3CA mutations in the colorectal tumorigenesis and to study the association of these events with clinicopathological parameters. In our study, DNA was extracted from 200 cases of human colorectal cancer tissue samples. KRAS, BRAF and PIK3CA mutation analysis was performed by PCR and pyrosequencing. Using statistical methods, we analyzed the relationships between the gene mutations and clinicopathological parameters. KRAS point mutations were detected in 63/200 patients (31.5%), with codon 12 mutations in 52/200 patients (26%), codon 13 mutations in 10/200 patients (5%) and codon 12.13 bi-mutations in 1/200 patients (0.5%). The V600E mutations of BRAF were detected in 14/200 patients (7%). PIK3CA point mutations (exon 9, exon 20) were detected in 25/200 (12.5%) patients, exon 9 mutatons in 12/200 patients (6%) and exon 20 mutations in 13/200 (6.5%). Our study suggested that both KRAS and BRAF mutations are exclusive, but KRAS and PIK3CA mutations are coexistent. The mutational status of BRAF did not correlate with Dukes' staging, histological type, age and gender. However, strong associations were found between KRAS, PIK3CA mutations and Dukes' staging (staging D, 12/25, 48%). Notably, our data indicated that colorectal cancers with KRAS and PIK3CA bi-mutations are more likely to develop into liver metastasis.     

Efficacy of first-line systemic treatment in correlation with BRAF V600E and different KRAS mutations in metastatic colorectal cancer - a single institution retrospective analysis

Background

KRAS mutation status in codons 12 and 13 is recognized as a predictive factor for resistance to anti-EGFR monoclonal antibodies. Despite having a wild type KRAS (wt-KRAS), not all patients with wt-KRAS respond to anti-EGFR antibody treatment. Additional mechanisms of resistance may activate mutations of the other main EGFR effectors pathway. Consequently, other molecular markers in colorectal cancer are needed to be evaluated to predict the response to therapy.

Patients and methods

In this retrospective study, objective responses (OR), time to progression (TTP), overall survival (OS) were analyzed in 176 metastatic colorectal cancer (mCRC) patients treated with first-line chemotherapy in combination with monoclonal antibodies in respect of KRAS status in codons 12 and 13 and BRAF mutational status.

Results

The KRAS mutations were found in 63 patients (35.8 %), the KRAS mutation in codon 12 in 53 patients (30.1%) and the KRAS mutation in codon 13 in 10 patients (5.7%). The BRAF V600E mutation was detected in 13 of 176 patients (7.4%). In the subgroup of mCRC patients having wt-KRAS and wild type BRAF (wt-BRAF), the objective response rates were higher (OR 54.0% ,CR 14.7%, PR 39.3%) than in the patients with wt-KRAS and mt-BRAF (OR 38.5%,CR 15.4%, PR 23.1%), the difference was not statistically significant (p= 0.378). Median OS in patients with wt-KRAS wt-BRAF, and in patients with wt-KRAS mt-BRAF, was 107.4 months and 45 months, respectively. The difference was statistically significant (p= 0.042). TTP in patients with wt-KRAS wt-BRAF, and in patients with wt-KRAS mt-BRAF, was 16 months and 12 months, respectively. The difference was not statistically significant (p= 0.558).

Conclusions

Patients with BRAF V600E mutation have statistically significantly worse prognosis than the patients with wt-BRAF and progress earlier during treatment. The definitive role of the BRAF V600E mutation as a prognostic and predictive factor for the response to anti-EGFR monoclonal antibodies needs to be analyzed in large prospective clinical studies.