中国人群远端结直肠腺瘤及腺癌患者的KRAS和BRAF基因突变
Analyses of KRAS and BRAF gene mutations in distal colorectal adenoma and adenocarcinoma

目的 研究KRAS和BRAF基因突变与远端结直肠腺瘤和腺癌病变的关系。方法 在肠镜观测下，采用活检钳收集远端结直肠腺瘤（腺瘤组，n=32）和腺癌（腺癌组，n=20）病变组织；抽提病变组织基因组DNA；并测定病变组织DNA的KRAS和BRAF基因序列。结果 32例腺瘤患者中，KRAS基因突变7例，突变率21.9%；20例腺癌患者中，KRAS基因突变7例，突变率35.0%。两组患者KRAS基因第12密码子和第13密码子较常见突变类型均为G12D和G13D。腺瘤组和腺癌组KRAS基因阳性突变率比较，差异无统计学意义（P>0.05）。两组患者均未见BRAF V600E突变。结论 中国人群腺癌和远端结直肠腺瘤BRAF V600E突变率较低，KRAS基因突变率较高，且KRAS基因突变率在腺癌和远端结直肠腺瘤无明显差异。
： Objective To investigate the relationship between mutations of KRAS and BRAF genes and distal colorectal adenoma and adenocarcinoma. Methods Lesion tissues of patients with distal colorectal adenoma (n=32, adenoma group) and adenocarcinoma (n=20, adenocarcinoma group) were obtained by endoscopic biopsy forceps. The genomic DNAs of lesion tissues were extracted and sequences of KRAS and BRAF genes were detected. Results Among 32 patients with adenoma, 7 of them were detected with KRAS mutations and the mutation rate was 21.9%. Among 20 patients with adenocarcinoma, 7 of them were detected with KRAS mutations and the mutation rate was 35.0%. Mutation types of codons 12 and 13 of KRAS gene of two groups were mainly G12D and G13D mutations. The difference of positive mutation rates of KRAS gene between two groups was not statistically significant (P>0.05). BRAF V600E mutation was not found in two groups. Conclusion Among Chinese patients with distal colorectal adenoma and adenocarcinoma, the mutation rate of BRAF V600E is low and that of KRAS gene is high. The difference of mutation rate of KRAS gene between distal colorectal adenoma and adenocarcinoma is not remarkable