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

Objective To map out the frequency and types of K-ras gene mutations present incolorectal and lung cancer patients; to evaluate the clinical applicability of a novel real-time double-loop probe PCR using the ADx-K-ras kit, and to compare its performance with the result by using traditional Sanger DNA sequencing in detection of somatic mutations of the tumor genes. Methods A total of 827 formalin-fixed paraffin-embedded (FFPE) blocks including 583 from the colorectal and 244 from the lung cancer patients were assayed. Genomic DNA of the sample tissues was extracted, purified and subjected to PCR amplification of K-ras gene codon 12 and 13 and DNA sequencing was carried on using both the traditional Sanger sequencing method and the ADx's K-ras mutation detection kit, respectively. The mutation rates for K-ras gene at codon 12 and 13, and the mutation frequencies detected by using both methods were analyzed. Results 533 out of 583 (91.4%) colorectal cancer samples and 144 out of 244 lung cancer samples(59.0%) were detected using the traditional Sanger DNA sequencing technique, and 583 out of 583(100.0%) colorectal plus 244 out of 244(100.0%) lung cancers were detected, respectively by using the ADx-K-ras kit. Of the 583 colorectal cancer samples, 192 (32.9%) showed mutations by using the ADx-K-ras kit in comparing with a result of 160 samples (27.4%) with K-ras gene mutation by using the traditional Sanger DNA sequencing technique. Of the 244 lung cancer samples, 26(10.7%) showed K-ras gene mutations by using ADx-K-ras kit, while in 144 samples detected by using the traditional Sanger DNA sequencing technique, only 12 samples (8.3%) showed K-ras gene mutations. In colorectal cancer analyzed, GGT→GAT at codon 12 was the most common event with 35.1% (66/188) mutations, followed by GGC→GAC at codon 13 with 26.6% (50/188) and GGT→GTT at codon 12 with 18.6% (35/188),while GGT→GCT at codon12 was the most rare with only 1.6% (3/188) of the total mutation cases. In patients with lung cancer analyzed,GGT→GTT at codon 12 was the most common mutation, accounting for 40.9% (9/22), and GGT→GCT at codon 12 the most rare with only about 4.5% (1/22) of the total mutation cases. Conclusions K-ras gene mutations were present in colorectal cases, and significantly more frequent than that in lung cancer. There were significant statistical differences between the two methods.ADx-K-ras real-time PCR showed much higher successful detection rates and mutation ratios compared to Sanger sequencing. As a result, the real-time PCR with ADx-K-ras kit proves to have a good clinical applicability and a strong advantage over the traditional Sanger DNA sequencing. It is a effective and reliable tool for clinical screening of somatic gene mutations in tumors.     

维生素D及其检测与腺癌

维生素D(VitD)是人体必需的重要物质,其经典生理作用为参与钙磷代谢,维持骨骼代谢平衡。近年来,流行病学调查研究表明,VitD水平与多种腺癌的患病率相关,补充VitD后可降低腺癌的发生和骨转移的发生率。针对乳腺、前列腺、甲状腺等腺癌的研究也发现,VitD通过与其受体结合后,作用于下游靶基因,产生一系列与肿瘤发生、发展相关的生物学效应,预示其在临床肿瘤检验中具有重要意义。     

维吾尔族肺腺癌患者的EGFR基因突变分析

背景与目的 表皮生长因子受体(epidermal growth factor receptor,EGFR)是一种跨细胞膜糖蛋白,属于受体型酪氨酸激酶家族.以吉非替尼为代表的EGFR酪氨酸激酶抑制剂对于EGFR突变的肺癌患者显示出良好的治疗效果,然而EGFR的突变率在不同民族和不同种族的人群中表现出较大差异.本研究旨在分析维吾尔族中肺腺癌患者肿瘤组织的EGFR基因突变情况,同时比较维吾尔族与汉族肺腺癌患者肿瘤组织EGFR基因突变率的差异性.方法 收集临床肺腺癌患者石蜡包埋组织标本138例,包括68例维吾尔族和70例汉族肺腺癌的样本,采用ARMS(amplification refractory mutation system,ARMS)PCR扩增方法检测EGFR基因外显子18、19、20及21的突变,x2分析对比维吾尔族和汉族肺腺癌EGFR基因突变差异.结果 138例肺腺癌患者中有43例EGFR基因突变,总突变率为31.2％,其中维吾尔族突变11例,突变率为16.2％,汉族突变32例,突变率为45.7％,维吾尔族肺腺癌EGFR突变率与汉族肺腺癌EGFR突变率比较有明显差异(P＜0.001),突变以外显子19-del和L858R为主要突变点.结论 维吾尔族中肺腺癌EGFR基因突变率为16.2％,汉族中EGFR基因突变率为45.7％,维吾尔族肺腺癌EGFR突变率明显低于我国汉族EGFR基因突变.