Genomic deletions of MSH2 and MLH1 in colorectal cancer families detected by a novel mutation detection approach.
Hereditary non-polyposis colorectal cancer is an autosomal dominant condition due to germline mutations in DNA-mismatch-repair genes, in particular MLH1, MSH2 and MSH6. Here we describe the application of a novel technique for the detection of genomic deletions in MLH1 and MSH2. This method, called multiplex ligation-dependent probe amplification, is a quantitative multiplex PCR approach to determine the relative copy number of each MLH1 and MSH2 exon. Mutation screening of genes was performed in 126 colorectal cancer families selected on the basis of clinical criteria and in addition, for a subset of families, the presence of microsatellite instability (MSI-high) in tumours. Thirty-eight germline mutations were detected in 37 (29.4%) of these kindreds, 31 of which have a predicted pathogenic effect. Among families with MSI-high tumours 65.7% harboured germline gene defects. Genomic deletions accounted for 54.8% of the pathogenic mutations. A complete deletion of the MLH1 gene was detected in two families. The multiplex ligation-dependent probe amplification approach is a rapid method for the detection of genomic deletions in MLH1 and MSH2. In addition, it reveals alterations that might escape detection using conventional diagnostic techniques. Multiplex ligation-dependent probe amplification might be considered as an early step in the molecular diagnosis of hereditary non-polyposis colorectal cancer.
Gille
J J P
JJ
Department of Clinical Genetics and Human Genetics, Cancer Family Clinic, VU University Medical Center, 1007 MB Amsterdam, The Netherlands. jjp.gille@vumc.nl
Hogervorst
F B L
FB
Pals
G
G
Wijnen
J Th
JT
van Schooten
R J
RJ
Dommering
C J
CJ
Meijer
G A
GA
Craanen
M E
ME
Nederlof
P M
PM
de Jong
D
D
McElgunn
C J
CJ
Schouten
J P
JP
Menko
F H
FH
D048868:Adaptor Proteins, Signal Transducing; D020137:Base Pair Mismatch / Q000235:genetics; D002352:Carrier Proteins; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000235:genetics*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins; D005190:Family; D005260:Female; D017353:Gene Deletion; D018095:Germ-Line Mutation; D006801:Humans; D008297:Male; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins; D010375:Pedigree; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000235:genetics*
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein