飞行时间质谱技术在结直肠癌K—ras基因突变检测中的应用

Application of matrix assisted laser desorption ionization-time of flight-mass spectrometry in detecting K-ras gene mutation of colorectal cancer

目的探讨MALDI—TOF—MS方法在检测结直肠癌K—ras基因突变中的实际临床价值。方法选取61例结直肠癌患者的肿瘤组织石蜡标本．应用常规测序和基质辅助激光解析／电离时间飞行质谱（MALDI-TOF-MS）两种方法．检测K-ras基因第2号外显子中第12及13位密码子的前两位碱基突变情况。结果常规测序法成功完成检测47例（77．0％），而MALDI-TOF-MS法成功检测所有61例标本。常规测序法检测样本总体突变率为30．0％（14／47），MALDI-TOF-MS法检测所有标本的总体突变率为36．1％（22／61）。6例样本常规测序法未检测到突变而质谱法检测到明确突变存在。14例样本经两种方法均检测出突变．且两种方法检测出的突变类型完全一致。2例样本未完成常规测序检测而通过质谱法检测出突变。结论相对常规测序而言，MALDI-TOF-MS法是一种对标本质量要求较低、更敏感的结直肠癌K-ras突变检测方法，有更好地临床价值。

Objective To investigate the clinical value of matrix assisted laser desorption ionization-time of flight-mass spectrometry （MALDI-TOF-MS） in detecting K-ras gene mutation. Methods Sixty-one paraffin-embeded specimens of colorectal cancer were selected. MALDI-TOF-MS and regular sequencing were used to test the mutation of codon 12 and 13 in K-ras exon 2. Results Only 47 specimens could be detected successfully in regular sequencing, while all the specimens were tested successfully in MALDI-TOF-MS. Fourteen specimens had K-ras mutation in regular sequencing （30.0%）, while 22 specimens had mutation in MALDI-TOF-MS （36.1%）. Six specimens with mutation were found in MALDI-TOF-MS but were wild-type in regular sequencing. Same mutation types from 14 specimens were confirmed by both regular sequencing and MALDI-TOF-MS. MALDI-TOF-MS was able to detect the mutation in 2 specimens that was not identified in regular sequencing. Conclusions MALDI-TOF-MS is a feasible approach of K-ras gene mutation testing in colorectal cancer, which is less demanding in terms of specimen quality and is more sensitive as compared to regular sequencing.