运用高灵敏度COLD-PCR法检测胰腺癌和结直肠癌患者KRAS基因突变

摘要

目的 评价COLD-PCR法检测胰腺癌和结直肠癌患者KRAS基因突变的价值.方法 采用COLD-PCR/Sanger测序法与普通PCR/Sanger测序法检测KRAS基因野生型结直肠癌细胞系SW116中混有的KRAS基因突变型和结直肠癌细胞系SW480中的KR4S基因突变,确定两种方法 的灵敏度,并采用两种方法 分别检测20例胰腺癌和39例结直肠癌患者石蜡包埋组织的KRAS基因突变,并评价两种方法 的符合率.结果 细胞系检测结果 显示,普通PCR/Sanger测序法和COLD-PCR/Sanger测序法检测KRAS基因突变的灵敏度分别为1∶20和1∶100(突变型:野生型).COLD-PCR/Sanger法检测20例胰腺癌患者KRAS基因突变率[75%(15/20)]高于普通PCR/Sanger测序法[40%(8/20),x2=5.013,P<0.05];COLD-PCR/Sanger测序法检测39例结直肠癌患者的KRAS基因突变率[44%(17/39)]高于普通PCR/Sanger测序法[31%(12/39),x2=1. 372,P=0.174)].两种方法 检测胰腺癌标本的符合率为65%,但一致性较差(Kappa=0.364,P<0.05);而两种方法 检测结直肠癌标本的符合率为87%,且一致性较好(Kappa=0.730,P<0.05).结论 COLD-PCR/Sanger测序法是一种高灵敏性检测胰腺癌和结直肠癌患者KRAS基因突变的方法 .%Objective To evaluate the significance of COLD-PCR in detecting KRAS mutation of pancreatic cancer and colorectal cancer patients. Methods First, set up COLD-PCR and compared the sensitivities of COLD-PCR/Sanger sequencing with PCR/Sanger sequencing using mixed cell lines ( KRAS wild-type cell line SW116 and KRAS mutant cell line SW480).Then, detected KRAS mutation of 20 formalin-fixed paraffin-embedded samples of pancreatic cancer and 39 formalin-fixed paraffin-embedded samples of colorectal cancer using PCR/Sanger sequencing and COLD-PCR/Sanger sequencing, respectively and compared the coincidence rate and consistency. Results The low detection limits of PCR/Sanger respectively. KRAS frequency detected by COLD-PCR/Sanger sequencing [75% (15/20)] in 20 cases of pancreatic cancer was higher than that detected by regular PCR/Sanger sequencing [40% ( 8/20 ) ,x2 =5.013, P < 0.05]. KRAS frequency detected by COLD-PCR/Sanger sequencing [44% (17/39)] in 39 cases of colorectal cancer was higher than that detected by regular PCR/Sanger sequencing [31% (12/39) ,x2 =1. 372, P = 0. 174]. The coincidence rate of these two methods was 0. 730 and the difference had no statistical significance. The coincidence rate of detecting KRAS mutation was 65% in pancreatic cancer and the results showed a good correlation between two methods and the two methods had bad agreement in diagnosis (Kappa = 0. 364, P < 0. 05 ). COLD-PCR/Sanger sequencing could detect more cases of KRAS mutations from pancreatic caner than regular PCR/Sanger sequencing. This was because there were many non-tumor cells in pancreatic tumor tissue and COLD-PCR/Sanger sequencing was more sensitive than regular PCR/Sanger sequencing. The coincidence rate of detecting KRAS mutations was 87% in colorectal cancer and the results were showed a good correlation between two methods and the two methods had substantical agreement in diagonsis ( Kappa = 0. 730, P < 0. 05 ) . Conclusion COLD-PCR/Sanger sequencing is highly sensitive to screen KRAS mutation in pancreatic cancer and colorectal cancer patients.