K-ras基因在胰腺疾病中突变的检测及其临床意义

Study on mutations of K-ras gene in pancreatic diseases

目的 探讨K ras基因突变在胰腺疾病中的临床意义和在胰腺癌诊断中的价值。方法 应用聚合酶链反应 单链构象多态性分析 (PCR SSCP)方法分别检测胰腺癌、癌旁组织、手术切缘正常组织、慢性胰腺炎石蜡包埋组织的K ras突变并进行DNA测序确认。结果 胰腺癌K ras 12密码子突变率 (79.2 % )显著高于慢性胰腺炎 (33.3% ,P <0 .0 1) ,且在切缘正常组织→癌周导管增生→癌周不典型增生→胰腺癌过程中 ,突变率有逐渐上升的趋势。突变方式以 12密码子GGT→GAT、GTT、CGT为主且同一例患者突变方式一致。结论 K ras基因突变在胰腺癌发生中起作用 ,但K ras基因突变作为胰腺癌诊断的分子标志缺乏特异性。

Objective To investigate the clinical significance of K-ras mutations in pancreatic diseases, specifically in the diagnosis of pancreatic carcinoma. Methods One hundred and seventeen surgical-resected pancreatic specimens, including 24 pancreatic ductal adenocarcinoma, 19 peritumoral ductal atypical hyperplasia, 58 peritumoral ductal hyperplasia, 19 normal duct at the tumor-free margin and 24 ductal lesion from chronic pancreatitis were obtained, and DNA was extracted from the specimens. Codon 12 K-ras mutations were examined using two-step polymerase chain reaction (PCR) combined with restriction enzyme digestion, non radioisotopic single-strand conformation polymorphism (SSCP) analysis and automated DNA sequencing. Results K-ras mutation rate in the lesion of pancreatic carcinoma was 79.2%(19/24), which was significantly higher than 33.3%(8/24) in the lesion of chronic pancreatitis( P <0.01). It was also found that K-ras mutation rate was progressively increased from normal duct at the tumor-free margin, peritumoral ductal hyperplasia, and peritumoral ductal atypical hyperplasia to pancreatic ductal adenocarcinoma. The mutation patterns of K-ras 12 codon in chronic pancreatitis were GGT→GAT, GTT and CGT, which were identical to those in pancreatic carcinoma. Conclusions K-ras mutation may play a role in the malignant transformation of pancreatic ductal cells but may not be specific enough to diagnose pancreatic carcinoma.