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

Abstract

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. 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. 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. 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.