Detection of KRAS,NRAS and BRAF gene mutations in colorectal carcinoma

VernacularTitle:结直肠癌患者 KRAS、NRAS 及 BRAF基因突变检测分析
Author: Keping ZHANG ¹ ; Jie XU ; Lixu YAN ; Xunhua LIU ; Fangping XU ; Yanhui LIU
Author Information

1. 广东省人民医院广东省医学科学院病理科
Keywords: Colorectal neoplasms; Genes,ras; Sequence analysis,DNA
From: Chinese Journal of Pathology 2015;(4):254-257
CountryChina
Language:Chinese
Abstract: Objective To investigate mutations frequencies of KRAS, NRAS and BRAF genes in colorectal carcinoma.Methods Tissue specimens from 200 colorectal cancer patients at diagnosis were collected and subject to KRAS,NRAS and BRAF mutation analyses by PCR-based direct DNA sequencing targeting exons 2, 3 and 4 of KRAS gene, exons 2, 3 and 4 of NRAS gene and exon 15 of BRAF gene. Results Activating mutations were detected in KRAS (44%, 88/200), NRAS (2%, 4/200) and BRAF (5%, 10/200) in this study cohort.Among KRAS mutations, 64.8% (57/88) occurred in codon 12 and 12.5%(11/88) occurred in codon 13.KRAS gene mutation in exon 3 mainly involved codons 59 and 61. KRAS gene mutation in exon 4 mainly involved codons 117 and 146.Conclusions Mutations at exon 2 of KRAS gene have the highest frequency in colorectal carcinoma.Expanding the detection sites of KRAS gene combined with NRAS and BRAF genes may help to identify patients who will most likely benefit from targeted therapies.