不同方法检测K-Ras基因突变与转移性结直肠癌疗效及预后的关系

目的 探讨直接测序法和肽核酸钳制PCR（PNA-PCR）法检测K-Ras基因突变状态与转移性结直肠癌患者疗效及预后的相关性。方法 收集110例转移性结直肠癌患者的石蜡包埋肿瘤组织，采用直接测序法和PNA-PCR法分别检测肿瘤组织的K-Ras基因第2外显子第12、13密码子的突变状态，并分析其与患者预后的关系。结果 直接测序法检测到43例K-Ras基因突变，PNA-PCR法除了检测出这些突变之外，还在直接测序法检测的野生型中发现了10例突变。对K-Ras突变状态与患者的预后分析发现，直接测序法检测的K-Ras野生型及突变型患者的中位生存时间（OS）分别为20.5个月和15.6个月（P=0.067）。PNA PCR法检测的野生型和突变型患者的中位OS分别为21.3个月和15.8个月（P=0.014）。两种方法检测的野生型与突变型的有效率和无病进展时间（PFS）差异均无统计学意义。按照这两种方法的检测结果分为3组，高突变组、低突变组和野生型组，仅高突变组与野生型组的OS差异有统计学意义（15.6个月vs.21.3个月，P=0.040）。Cox多因素分析显示，ECOG评分（HR=2.70，95％CI：1.39～5.25，P=0.003）和K-Ras丰度（HR=1.52，95％CI：1.52～2.19，P=0.026）与患者的预后相关。结论 K-Ras突变不是以伊立替康或奥沙利铂为主方案的疗效预测因子。PNA-PCR法检测的K-Ras突变状态与患者的预后有关。建议用PNA-PCR法确定野生型患者，而突变型患者则用直接测序法来确定。

Correlation between K-Ras mutations in different detections and prognosis of colorectal cancer

Objective To investigate the possible signal pathway of multi-drug resistant P-glycoprotein（P-gp）expression induced by cyclooxygenase-2（COX-2）in hunman gastric adenocarcinoma cell line SGC-7901 stimulating with pacliaxel（TAX）.Methods The effects of TAX on SGC-7901 cells growth was assessed by MTT assay,and so did the effects of COX-2 selective inhibitor NS-398 and nuclear factor-κB（NF-κB） pathway inhibitor pyrrolidine dithiocarbamate（PDTC）.The effect of a dose-ranging TAX and the change of combining NS-398 or PDTC with TAX on the COX-2,p65 and P-gp expression were detected by Western blotting.Results TAX,NS-398 and PDTC all had the effect of cellular toxicity on SGC-7901 cell line growth in a dose-dependent manner.When the dose of TAX（0.1,0.3,0.5μmol/L） increased,the expression of COX-2,p65 and P-gp showed rising trend in SGC-7901 cell line.And the expression of three proteins could decrease with the increase of dose and extension of time after combined with NS-398（5,10μmol/L）.When combined with PDTC（0.2μmol/L）,the expression of p65 and P-gp decreased significantly.Conclusion COX-2 may induce the expression of P-gp in SGC-7901 cell line via NF-κB pathway with the stimulation of TAX.