胰腺癌中EGFR、KRAS、BRAF基因突变状况分析及意义

目的:检测胰腺癌组织EGFR、KRAS、BRAF基因突变状况,为胰腺癌EGFR靶向治疗研究奠定基础.方法:提取胰腺癌及胰腺良性病变石蜡组织切片中基因组DNA,PCR扩增EGFR 18、19、21外显子片段,KRAS2、3外显子片段,BRAF15外显子片段,采用直接测序法检测其突变状况.结果:32例胰腺癌患者中有24例患者存在KRAS基因突变,10例良性病变组织均未发现突变,两者差异具有统计学意义(x2=14.57,P=1.35× 10-4),其中22例12密码子突变(G12D14例,G12V8例)；2例61密码子突变(Q61L).所有检测样本中未见BRAF突变.共3例EGFR突变,其中包括1例19外显子突变(de1746-750),2例21外显子突变(L858R),10例良性病变组织未见突变.结论:在胰腺癌中KRAS基因突变可能为EGFR通路失调的主要原因,其次是EGFR突变,BRAF突变未见.

Analysis and significance of EGFR,KRAS,and BRAF gene mutations in pancreatic cancer

Objective To detect the EGFR,KRAS,BRAF gene mutation of pancreatic cancer by direct sequencing,to lay the foundation for the mechanism study of the resistance to EGFR-targeted therapy in pancreatic cancers.Methods The genomic DNA was extracted from paraffin tissue sections of pancreatic cancer and pancreatic benign lesions,respectively.EGFR 18,19,21 exon fragments,KRAS 2,3 exon fragments,and BRAF 15 exon fragments were amplificed by PCR and were directly sequenced to detect their mutation status.Results 24 cases were found the KRAS gene mutation in 32 patients with pancreatic cancer,and 10 benign lesions were not found mutations,the difference was significant(?字2 = 14.57,P = 1.35 × 10-4),including 22 cases with codon 12 mutation(14 cases with G12D,8 cases with G12V);two cases with codon 61 mutation(Q61L).No BRAF mutation in all samples was detected;3 cases were found with EGFR mutations,including 1 case with exon 19 mutation(del746-750),2 cases with exon 21 mutation(L858R),10 patients with benign lesions had no mutation.Conclusion The mutation rate of EGFR and BRAF in pancreatic cancer patients is low,but the mutations may play an important role in resistance to EGFR-targeted therapy in the pancreatic cancer patients with wild-type KRAS gene.