摘要目的 探讨结直肠腺癌KRAS基因突变的检测及其临床意义.方法 应用PCR直接测序法检测440例结直肠腺癌患者中KRAS基因第2号外显子突变状况,分析KRAS基因突变与患者性别、年龄、组织学分级及临床分期的关系.结果 440例中男性257例,女性183例,年龄22 ～ 88岁,中位年龄60岁.414例为手术标本,15例为肠镜活检组织,11例为肝转移灶穿刺组织.其中146例检测到KRAS基因第2号外显子突变,突变率为33.2％ (146/440).146例中,第12位密码子突变118例,包括突变类型有35G＞A(Gly12Asp) 62例、35G＞T(Gly12Val) 35例、34G＞T(Gly12Cys)9例、34G＞ A(Gly12Ser)6例、35G＞ C(Gly12Ala)5例、34G＞ C(Gly12Arg)1例,第13位密码子突变27例,包括突变类型有38G＞ A(Gly13Asp) 25例、38G＞ C(Gly13 Val)1例、37G＞ T(Gly13Cys)1例,另发现1例第14位密码子突变,40G＞ A(Val14lle).KRAS基因或第12位密码子突变与患者性别有一定的关系,女性突变率高(P值分别为0.021和0.030),KRAS基因或第12位密码子突变与患者性别的差异在临床分期Ⅲ期患者中仍存在(P值分别为0.007和0.003),但在临床分期Ⅰ期、Ⅱ期和Ⅳ期的患者中差异不明显.KRAS基因或第12位密码子突变与临床特征有一定的关系.临床Ⅱ期和临床Ⅳ期之间KRAS突变率或第12位密码子的突变率差异有统计学意义,P值分别为0.028和0.034.Ⅲ、Ⅳ期之间第12位密码子突变率差异有统计学意义(P=0.011).第13位密码子突变与临床分期无关.结论 结直肠腺癌中约三分之一的患者存在KRAS基因第2号外显子突变,KRAS基因突变可能与患者性别有一定的关系,PCR直接测序可稳定地检测KRAS基因突变状况.

abstractsObjective To explore the clinical significance of KRAS mutation detection in colorectal adenocarcinoma.Methods Paraffin-embedded tissue specimens were obtained from 440 patients with colorectal adenocarcinoma.The genomic DNA was extracted.Mutations of exon 2 of KRAS gene were examined by PCR and direct seqaencing.Results Somatic mutations of KRAS gene were identified in 146 cases,with the mutation rate of 33.2％ (146/440).Among these 146 patients,KRAS mutation involved codon 12 in 118 patients,including 35G ＞ A (Gly12Asp,62 cases),35G ＞ T (Gly12Val,35 cases),34G ＞ T (Gly12Cys,9 cases),34G ＞ A (Gly12Ser,6 cases),35G ＞ C (Gly12Ala,5 cases),and 34G＞ C (Gly12Arg,1 case); in 27 patients the mutation involved codon 13,including 38G ＞ A (Gly13Asp,25 cases),38G ＞ C (Gly13 Val,1 case) and 37G ＞ T (Gly13 Cys,1 case) ; and in one patient,the mutation involved codon 14 with 40G ＞ A (Val14Ile).The status of KRAS or codon 12 mutations in colorectal adenocarcinoma was related to patients' gender (P =0.021 and P =0.030,respectively),and this significant correlation to females was conserved in clinical stage Ⅲ (P =0.007 and P =0.003,respectively),but not in stages Ⅰ,Ⅱ,and Ⅳ.The statns of KRAS or codon 12 mutations was also related to tumor stage.Between stage Ⅱ and stage Ⅳ,the mutation rate of KRAS and codon 12 showed significant difference (P =0.028 and 0.034,respectively).Between stage Ⅲ and stage Ⅳ,only the codon 12 mutation rate showed significant difference (P =O.011).Codon 13 mutation was not related to tumor stage.Conclusion About one third of patients with colorectal adenocarcinoma have KRAS gene mutation,which might be related to patients' gender; and could be consistently detected by PCR and direct sequencing.