中国新疆维吾尔族人群中肺癌驱动基因的表达

背景与目的：肺癌的发病率和肿瘤相关死亡率居当前世界各地恶性肿瘤的首位。肺癌亦存在多种驱动基因。各民族间的差异反映出肺癌的不同基因突变存在差异。该研究旨在探讨新疆维吾尔族患者中肺癌驱动基因的表达状况。方法：收集维吾尔族肺癌患者组织标本43例,采用扩增受阻突变系统(amplification refractory mutation system,ARMS)检测EGFR基因表达,采用实时荧光定量聚合酶链反应(real-time fluorescent quantitative polymerase chain reaction,RTFQ-PCR)检测K-ras、ALK、ROS1、BRAF及PIK3CA基因表达,分析肺癌驱动基因突变与新疆维吾尔族肺癌患者临床病理特征之间的相关性。结果：43例标本中,EGFR基因突变率为11.63%,其中腺癌及鳞癌EGFR基因突变检出率分别为26.67%和4.76%;大细胞癌、腺鳞癌及小细胞肺癌均未测出EGFR基因突变。肺腺癌患者EGFR基因突变率为26.67%,明显高于非腺癌者的3.57%,差异有统计学意义(P=0.024)。K-ras12/13杂合突变6例,突变检出率为16.28%(6/43);PIK3CA杂合突变2例,突变检出率为4.65%(2/43)。1例发生EGFR基因与K-ras基因同时突变。维吾尔族肺癌患者EGFR基因突变与年龄、性别、吸烟状况、TNM分期、ECOG评分均无关。43例标本中均未见ALK、ROS1融合基因及BRAF基因突变。结论：与亚洲人群相比,新疆维吾尔族肺癌患者EGFR突变率较低,K-ras突变率高,类似于欧美高加索人群的突变特点。     

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。     

靶向高通量测序在非小细胞肺癌中的临床应用

  目的  对8种与非小细胞肺癌（non-small cell lung cancer,NSCLC）个性化治疗高度相关的驱动基因进行检测,分析基因变异与临床病理特征的关系。  方法  收集天津医科大学肿瘤医院2016年6月至2017年8月212例NSCLC患者样本,对EGFR、KRAS、BRAF、ALK、MET、ERBB2、ROS1、RET 8种基因进行高通量测序。  结果  8种基因中EGFR基因变异率高达52.8%,其次为KRAS（8.5%）、ALK（8.0%）、ERBB2（6.1%）、MET（3.8%）、BRAF（1.4%）、RET（0.9%）、ROS1（0.9%）,75%样本检出至少1个驱动基因变异,驱动基因变异间呈现强烈互斥。最常见的EGFR突变为19外显子缺失和L858R突变,EGFR T790M突变与前面两个突变位点伴随出现。19外显子缺失患者携带非EGFR T790M突变比例低于L858R突变患者携带非EGFR T790M突变比例（P=0.04）。15.2%EGFR突变伴EGFR扩增,携带EGFR扩增且EGFR突变率 > 40%患者比例高于无EGFR扩增且EGFR突变率 > 40%患者（P < 0.01）。女性、不吸烟、腺癌患者易发生EGFR特别是EGFR敏感突变（P < 0.01）。肺腺癌（P=0.013）、临床分期晚（P=0.048）、淋巴结转移（P=0.027）患者携带EGFR扩增比例高。男性（P=0.009）、左侧肺癌（P=0.048）,吸烟患者（P=0.037）KRAS突变发生率较高。携带非KRAS突变、ALK融合的患者更年轻（P=0.005,P=0.031）,而携带KRAS突变患者年龄较高（P=0.055）。  结论  高通量测序可同时高效检测NSCLC患者中8种与靶向治疗相关驱动基因的变异谱,为临床医生的个体化诊疗提供参考,以多基因为基础的高通量测序为NSCLC诊疗提供更多的可能性。      

非小细胞肺癌十基因突变联合检测分析

目的：探讨运用扩增阻滞突变系统(Amplification Refractory Mutation System, ARMS)法检测EGFR、ALK、ROS1、RET、KRAS、NRAS、PIK3CA、BRAF、HER2和MET十基因在非小细胞肺癌的突变情况,分析其与临床病理的关系,探索十基因突变联合检测的临床应用价值。方法：收集2019年5月至2019年10月在四川省肿瘤医院病理确诊为非小细胞肺癌患者406例,其中石蜡包埋样本400例,细胞涂片6例,采取柱提法提取DNA和RNA,突变检测采用ARMS法。结果：非小细胞肺癌十基因联合检测的总突变频率为73.2%（297/406）,各驱动基因突变分布为：EGFR：51.0%（207/406)、KRAS：9.6%（39/406）、ALK融合：6.2%（25/406)、ROS1融合：2.5%（10/406）、RET融合 ：2.2%（9/406）、NRAS：0.2%（1/406）、PIK3CA：2.2% （9/406）、BRAF：1.0% （4/406）、HER2：2.2% （9/406）、MET 14外显子跳跃：0.7% （3/406）。肺腺癌EGFR突变频率高于肺鳞癌;女性患者EGFR与HER2 20ins突变频率高于男性,男性患者KRAS突变频率高于女性;年龄低于60岁的患者ROS1突变频率高于60岁以上的患者。十基因突变率在原发灶和转移灶之间无差异,冰冻后样本突变检出率高于其他类型样本。另外在30例样本中检出双突变,突变类型为18种,突变率达到7.4%;57%的双突变样本来源于初诊患者,没有观察到独特的组织病理特征。双突变患者在年龄和病理组织学分型上与单突变患者无差异,但易发生于女性患者。结论：ARMS法非小细胞肺癌十基因联合检测可一次获得更多基因突变信息,为分子靶向用药提供更加全面的指导信息,对于临床取材量少标本意义重大,多基因联合检测提供的共突变信息能够更全面地指导临床治疗。     

非小细胞肺癌中ALK、KRAS蛋白表达及其临床意义

目的 探究非小细胞肺癌中ALK、KRAS蛋白表达及其临床意义。方法 选取非小细胞肺癌患者50例,采用免疫组化法检测患者ALK和KRAS的表达水平,分析ALK和KRAS表达与NSCLC患者临床特征的关系。观察疾病预后情况,采用多因素Logistic回归分析影响NSCLC患者预后的危险因素。结果 不同TNM分期患者ALK和KRAS阳性表达差异有统计学意义(P<0.05),而不同性别、年龄、吸烟状态和肿瘤直径患者ALK和KRAS表达差异无统计学意义(P>0.05)。肿瘤直径、TNM分期、ALK和KRAS表达情况是影响非小细胞癌患者预后的相关因素(P<0.05),多因素Logistic回归分析显示,TNM分期Ⅲ～Ⅳ期、肿瘤直径>3 cm、ALK和KRAS表达阳性为影响NSCLC患者预后的独立危险因素(P<0.05)。结论 ALK和KRAS表达与非小细胞肺癌患者预后密切相关,为进一步研究非小细胞肺癌患者病情提供了数据参考。     

肺癌驱动基因及其靶向治疗药物

随着肿瘤分子生物学的发展,针对肺癌驱动基因的分子靶向治疗已成为晚期肺癌不可或缺的一部分。目前最成功的例子就是针对表皮生长因子受体（EGFR）和间变性淋巴瘤激酶（ALK）的靶向治疗。现在越来越多的肺癌驱动基因突变已被发现,包括ROS1基因融合、成纤维细胞生长因子1扩增、KRAS、BRAF和PIK3 CA基因突变等。明确这些基因突变的频率及临床意义,对指导肺癌的临床治疗有着重要的意义。     

共突变基因与晚期非小细胞肺癌靶向治疗预后生存的相关性分析

目的:进一步验证晚期表皮生长因子受体（epidermal growth factor receptor,EGFR）突变非小细胞肺癌(non-small cell lung cancer,NSCLC)靶向治疗预后生存情况,探讨共突变基因与患者预后生存的相关性。方法:回顾性分析2016年01月至2019年12月我院经病理确诊为晚期NSCLC,二代测序（next-generation sequencing,NGS）为EGFR突变阳性,且使用表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitor,EGFR-TKI）一代药物作为一线治疗的102例患者的病历和随访资料。收集其临床病理特征、治疗前的检验结果、基因检测报告、共突变基因和随访信息。采用Cox回归模型分析共突变基因与无疾病进展生存期（progression-free survival,PFS）的相关性。通过基因表达谱数据动态分析（Gene Expression Profiling Interactive Analysis,GEPIA）公共数据库分析磷脂酞肌醇-3-激酶催化亚单位α基因（phosphoinositide-3-kinase catalytic alpha polypeptide gene,PIK3CA）、人类表皮生长因子受体2（human epidermal growth factor receptor 2,HER-2）、间质表皮转化因子（mesenchymal-epithelial transition factor,MET）三种共突变基因与肺癌总生存期（overall survival,OS）和无病生存期（disease-free survival,DFS）的相关性。结果:102例一线靶向治疗的晚期NSCLC患者中位PFS为10个月。单因素分析表明,EGFR突变合并PIK3CA突变的患者一线靶向治疗的中位PFS为8个月,不合并PIK3CA突变患者的中位PFS为11个月,差异有统计学意义（P=0.037）;EGFR突变合并T790M突变患者的中位PFS为6个月,不合并T790M突变患者中位PFS为10个月,差异有统计学意义（P=0.043）;EGFR突变合并HER-2扩增的患者中位PFS为7个月,不合并HER-2扩增的患者中位PFS为10个月,差异有统计学意义（P=0.048）;EGFR突变合并MET扩增的患者中位PFS为3个月,不合并MET扩增的患者中位PFS为10个月,差异有统计学意义（P=0.001）。多因素分析显示,合并PIK3CA突变（HR=0.536,95%CI:0.302~0.951,P=0.033）、HER-2扩增（HR=0.359,95%CI:0.142~0.909,P=0.031）、MET扩增（HR=0.139,95%CI:0.042~0.464,P=0.001）是PFS的独立预后因素。PIK3CA基因与晚期NSCLC的DFS有相关性（P<0.05）。结论:晚期NSCLC靶向治疗前合并PIK3CA突变、HER-2扩增、MET扩增是患者PFS的独立影响因素。     

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。     

晚期胃癌患者血液ctDNA水平与组织学基因检测的一致性比较

目的:比较晚期胃癌患者外周血循环肿瘤DNA（circulating tumor DNA,ctDNA）与组织学基因检测的一致性,讨论ctDNA的临床应用价值。方法:根据纳排标准最终收集30例晚期初诊初治胃癌患者的实体组织标本及血浆标本,并用二代测序(next generationg sequencing,NGS)技术分别检测68个基因在其中的表达状况。对比ctDNA与组织学检测基因的检出一致性及差异,评估其用于诊断胃癌的敏感度、特异度。并按胃癌突变基因分层进一步评估ctDNA的检出率。结果:30例患者中检出的基因突变总共138个,其中组织学标本中总共检出71个,ctDNA中总共检出67个。ctDNA对比组织学检测基因诊断胃癌的灵敏度为31.5%,特异度为63.6%,一致率为43.3%。单基因检测分析突变最多的基因前三位为TP53、PIK3CA、HER-2。其中对PIK3CA的检测,组织学和ctDNA两种方法差异有统计学意义（P＜0.05）。TP53、PIK3CA、HER-2、EGFR、KRAS在组织学中检出丰度大于1,但在ctDNA中小于1。有PIK3CA突变的患者中,共存的其他致癌基因突变位点包括KRAS 2例、BRAF 2例、EGFR 4例。有HER-2突变的患者中,共存PIK3CA突变者4例,共存KRAS突变者3例。结论:ctDNA检测虽然在晚期胃癌患者的诊断中敏感度、特异度低于组织标本基因检测,但其标本易获、接受度高,可作为基因检测的补充、备选。实体组织检出相同基因的突变丰度总体高于ctDNA。TP53、PIK3CA、HER-2、EGFR等基因在ctDNA中的检出有利于指导胃癌治疗及预后评估,尤其PIK3CA在ctDNA中高于组织中的检出率。ctDNA检测可为胃癌患者的精准靶向治疗提供依据。     

非小细胞肺癌原发灶和转移淋巴结EGFR、KRAS和MET基因状态比较

目的:比较配对的原发肺癌灶和转移淋巴结EGFR、KRAS和MET基因状态,探讨NSCLC原发灶和转移淋巴结基因变化规律并指导临床实践。方法:22例手术切除的Ⅲa期非小细胞肺癌,术前未经靶向和化学治疗,获取配对的原发灶和N2站转移淋巴结。采用直接测序法检测EGFR外显子19-21,KRAS密码子12和13突变,实时定量PCR检测MET基因拷贝数。结果:原发灶和N2转移淋巴结中EGFR基因突变率分别为7/22例(31.82%)和6/22例(27.27%),EGFR基因型一致率达95.45%。KRAS基因突变率分别为2/22例(9.09%)和1/22例(4.55%)。转移淋巴结MET基因拷贝数(1.54±0.71)显著高于原发灶(1.19±0.41),P=0.038。EGFR 19和21基因突变与原发灶(P=0.24)、转移灶(P=0.97)的MET基因拷贝数以及原发灶和转移灶MET基因拷贝数变化(P=0.69)之间都无相关性,P>0.05。不同的EGFR基因状态和MET基因拷贝数其1年无病生存无显著差异(P>0.05)。结论:肺癌原发灶和相应转移淋巴结中EGFR基因突变较稳定;EGFR敏感基因突变与MET基因拷贝数可能无关;而未经EGFR-TKI治疗的肺癌患者其MET基因拷贝数在淋巴结转移时即已开始出现明显增高。     

非小细胞肺癌组织MET和EGFR基因扩增与预后相关性分析

目的：探讨非小细胞肺癌（non-smfllleelllungcancer,NSCLC）患者中肝细胞生长因子受体（MET）基因和表皮生长因子受体（epidermalgrowthfactorreceptor,EGFR）基因扩增与临床病理特征及预后的关系。方法：回顾分析唐山市协和医院（48例）和唐山市人民医院（109例）2001—01—2007—01手术切除的NSCLC石蜡包埋标本157例。应用荧光原位杂交（fluorescenceinsituhybridization,FISH）检测NSCLCMET、EGFR基因扩增情况,并结合临床病理资料进行统计分析。应用SPSS16．0进行统计分析,Kaplan-Meier模型分析中住生存期（overallsurvival,0S）,Log—rank检验比较生存曲线,多因素分析采用Cox回归模型。结果：157例NSCLC患者标本中,EGFR基因扩增70例（44．6％）。EGFR基因扩增与年龄、性别、吸烟状态、组织类型和TNM分期无关,P〉0．05。157例NSCLC患者标本中,MET基因扩增25例（15．9％）。EGFR扩增患者MET扩增率为22．9％,高于无EGFR扩增患者MET扩增率10．3％,P=0．033。MET基因扩增与年龄、性别、吸烟状态、组织类型和TNM分期无关,P〉0．05。Kaplan-Meier生存分析显示,I＋Ⅱ期中位生存期为51个月,明显高于Ⅲ＋Ⅳ期中位生存期29个月,P=0．001。EGFRFISH阳性患者中位0s为33个月与EGFRFISH阴性患者中位0s39个月比较,差异无统计学意义,P=0．495。METFISH阳性患者中位0S为29个月,低于METFISH阴性患者37个月,P=0．044。患者0s与病理类型、年龄、性别和吸烟状态无相关性,P〉0．05。多因素分析显示,临床分期、MET基因扩增与OS有关（相对危险度为12．573、6．892,P值分别为0．015、0．018）。结论：临床Ⅲ＋Ⅳ期和MET基因扩增NSCLC患者预后不良,EGFR基因扩增与NSCLC患者预后无关。     

PIK3CA mutations and copy number gains in human lung cancers

We investigated the frequency and function of mutations and increased copy number of the PIK3CA gene in lung cancers. PIK3CA mutations are one of the most common gene changes present in human cancers. We analyzed the mutational status of exons 9 and 20 and gene copy number of PIK3CA using 86 non-small cell lung cancer (NSCLC) cell lines, 43 small cell lung cancer (SCLC) cell lines, 3 extrapulmonary small cell cancer (ExPuSC) cell lines, and 691 resected NSCLC tumors and studied the relationship between PIK3CA alterations and mutational status of epidermal growth factor receptor (EGFR) signaling pathway genes (EGFR, KRAS, HER2, and BRAF). We also determined PIK3CA expression and activity and correlated the findings with effects on cell growth. We identified mutations in 4.7% of NSCLC cell lines and 1.6% of tumors of all major histologic types. Mutations in cell lines of small cell origin were limited to two ExPuSC cell lines. PIK3CA copy number gains were more frequent in squamous cell carcinoma (33.1%) than in adenocarcinoma (6.2%) or SCLC lines (4.7%). Mutational status of PIK3CA was not mutually exclusive to EGFR or KRAS. PIK3CA alterations were associated with increased phosphatidylinositol 3-kinase activity and phosphorylated Akt expression. RNA interference-mediated knockdown of PIK3CA inhibited colony formation of cell lines with PIK3CA mutations or gains but was not effective in PIK3CA wild-type cells. PIK3CA mutations or gains are present in a subset of lung cancers and are of functional importance.     

Survival and prognosis analyses of concurrent PIK3CA mutations in EGFR mutant non-small cell lung cancer treated with EGFR tyrosine kinase inhibitors

In non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation, the prognostic impact of a concurrent Phosphoinositide-3-kinase catalytic alpha polypeptide (PIK3CA) mutation was still unknown. Some studies have shown that EGFR mutant NSCLC patients treated with EGFR tyrosine kinase inhibitors (TKIs) when concurrent PIK3CA mutation have a worse prognosis and shorter survival time. This study conducted a retrospective analysis of NSCLC patients with EGFR mutant or concurrent PIK3CA mutations from January 2015 to October 2019 in the First Affiliated Hospital of Nanchang University. Relative to EGFR alone mutations (Single-Mt), we found that NSCLC patients with EGFR mutations coexisting with PIK3CA mutations (Double-Mt) treated with EGFR-TKIs had a shorter median time to progression (TTP): 7.8 months versus 10.9 months (Double-Mt versus Single-Mt, P = 0.001), and decrease in median overall survival (OS): 20.6 months versus 32.4 months (P < 0.001). The objective response rate (ORR) between Double-Mt and Single-Mt was 36.7% versus 61.9% (P = 0.044), disease control rates (DCR) was 80.1% versus 91.7% (P = 0.179). Obviously, EGFR-TKIs for EGFR mutate NSCLC patients when concurrent PIK3CA mutations have a worse prognosis and shorter survival time.     

PTEN gene expression and mutations in the PIK3CA gene as predictors of clinical benefit to anti-epidermal growth factor receptor antibody therapy in patients with KRAS wild-type metastatic colorectal cancer

PurposeTo identify novel genetic markers predictive of clinical benefit from epidermal growth factor receptor–directed antibody therapy in patients with metastatic colorectal cancer.Patients and MethodsSeventy-six consecutive patients who received cetuximab or panitumumab, either alone or in combination with chemotherapy and with available tumor tissue were included. Tumor tissue was tested by pyrosequencing for mutations at known hot spots in the KRAS, BRAF, PIK3CA, PIK3R1, AKT1, and PTEN genes. PTEN promoter methylation status was analyzed by methylation-specific polymerase chain reaction, and expression was determined by immunohistochemistry (IHC). Forty-four patients had 4 weeks of therapy and were considered for clinical correlates.ResultsConsistent with previous studies, KRAS gene mutations were associated with a shorter progression-free survival (PFS) and overall survival (OS). Among the patients with wild-type KRAS, preservation of PTEN expression and PIK3CA wild-type status was associated with improved OS (median OS, 80.4 vs. 32.5 weeks; hazard ratio, 0.33; P = .0008) and a trend toward improved PFS (median PFS, 24.8 vs. 15.2 weeks; hazard ratio, 0.51; P = .06), compared with PTEN-negative or PIK3CA-mutant tumors. PTEN methylation was more common in the metastatic samples than in the primary samples (P = .02). The simultaneous presence of methylation and mutation in the PTEN gene was associated with IHC negativity (P = .026).ConclusionIn addition to KRAS mutation, loss of PTEN expression (by IHC) and PIK3CA mutation is likely to be predictive of a lack of benefit to anti-EGFR therapy in metastatic colorectal cancer. PTEN promoter methylation and mutation status was predictive of PTEN expression and may be used as an alternative means of predicting response to EGFR-targeted therapy.     

Clinical characteristics associated with ALK rearrangements in never-smokers with pulmonary adenocarcinoma

Objectives

Anaplastic lymphoma kinase (ALK) rearrangement is a validated predictive marker to define patients with non-small cell lung cancer (NSCLC) who can benefit from selective ALK inhibitors. Therefore, accurate assessment of its prevalence and clinical characteristics is increasingly important in the treatment of NSCLC. Also, this ALK rearrangement was previously reported to be more common in patients with no smoking history or those with adenocarcinoma.

Patients and methods

Never-smokers with completely resected pulmonary adenocarcinoma were screened for ALK rearrangements using Nanostring's gene expression platform. Clinicopathologic data, such as information about epidermal growth factor receptor (EGFR) and KRAS mutation status were retrospectively reviewed.

Results

Of 231 tumors screened, 20 (9%) had an ALK rearrangement and all were confirmed to be positive with immunohistochemical and fluorescent in situ hybridization analysis. Of the tumors with available data on the EGFR/KRAS mutation status, EGFR and KRAS mutation rates were 64% (69/108) and 5% (5/102), respectively. Amongst the tumors that were free of EGFR and KRAS mutations, the proportion of ALK rearrangements reached up to 33%. At the time of data cut-off, total of 68 tumors were recurred. Although the recurrence rate was similar between the ALK-positive and negative groups (30% vs. 29%), there was a tendency for ALK-positive tumors to recur more frequently in the pleural space (15% vs. 5%). The five-year disease-free survival (61%) and overall survival rates (79%) in the ALK-positive group were similar to those in the ALK-negative group (51% and 83%, respectively). Even after excluding two patients treated with crizotinib after disease recurrence, overall survival was similar between the two groups.

Conclusion

In an NSCLC subpopulation based on smoking history, histology, and EGFR and KRAS mutation status, the prevalence of ALK rearrangements is considerably high. However, ALK rearrangement status itself has no prognostic relevance in patients with completely resected NSCLC.     

Gene status of head and neck squamous cell carcinoma cell lines and cetuximab-mediated biological activities

Cetuximab is a chimeric IgG1 monoclonal antibody that targets epidermal growth factor receptor (EGFR). Cetuximab binds to EGFR and prevents phosphorylation of EGFR. Moreover, preclinical results have shown the ability of cetuximab to induce either complement-mediated tumor cell killing (CDC) or antibody-dependent cell-mediated-cytotoxicity (ADCC). We previously reported mutation in EGFR regarding head and neck squamous cell carcinoma (HNSCC) cell lines. In the present study, we analyzed the same 16 HNSCC cell lines for mutations in KRAS, PIK3CA, BRAF and PTEN. Furthermore, we evaluated cetuximab-mediated biological activities (antiproliferative effect by the MTT assay and ADCC) regarding these cell lines. Mutations in PIK3CA and PTEN were observed in two cell lines (2/16, 12.5%), but no mutation was observed in KRAS and BRAF. The antiproliferative effect of cetuximab by the MTT assay was not strong, and no correlation was observed between the antiproliferative effect of cetuximab and mutations in EGFR, KRAS, PIK3CA, BRAF and PTEN in these cell lines. Therefore, the mutation status of EGFR and downstream molecules were not useful for predicting the antitumor effects of cetuximab on HNSCC. Cetuximab-mediated ADCC was observed in these cell lines and might have been influenced by the expression of EGFR. Therefore, cetuximab-mediated ADCC seems to be an important part of the antitumor mechanisms of cetuximab and the expression levels of EGFR might influence the antitumor activity of cetuximab. Therefore, besides the antiproliferative effect of cetuximab by the MTT assay, it appeared important to evaluate cetuximab-mediated ADCC as well as EGFR expression in HNSCC cells.