In vitro transcription/translation assay for the screening of hMLH1 and hMSH2 mutations in familial colon cancer.
OBJECTIVE
Hereditary nonpolyposis colorectal cancer (HNPCC) has been linked recently to a defect in repairing mismatched nucleotides in DNA. The aim of this study was to screen for germline mutations that result in prematurely truncated proteins in two of the mismatch repair genes identified at this time, hMLH1 and hMSH2, in a consecutive series of patients belonging to familial aggregations of colorectal cancer.


METHODS
Nineteen individuals with colorectal cancer from 19 families were consecutively referred because of a strong positive family history of colorectal cancer. Premature truncation mutations in hMLH1 and hMSH2 were sought from lymphocyte RNA by using an in vitro transcription/translation (IVTT) assay.


RESULTS
Protein truncating mutations in the hMLH1 or hMSH2 genes were found in 50% of families with HNPCC (6 of 12) but were not observed in any of the remaining familial aggregations that did not fulfill the standard criteria for HNPCC. In some of the IVTT-positive samples, the mutations were characterized by genomic sequencing.


CONCLUSIONS
IVTT may be a practical method to accomplish primary screening of germline mutations in DNA mismatch pair genes in HNPCC; however, a broader approach is necessary to obtain a more complete picture of the mutational spectrum in HNPCC and other familial aggregations of colorectal cancer.
Luce
M C
MC
Roche Biomedical Laboratories, Research Triangle Park, North Carolina, USA.
Marra
G
G
Chauhan
D P
DP
Laghi
L
L
Carethers
J M
JM
Cherian
S P
SP
Hawn
M
M
Binnie
C G
CG
Kam-Morgan
L N
LN
Cayouette
M C
MC
D001483:Base Sequence; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D014158:Transcription, Genetic