[Mutation analysis on MSH2 and MLH1 genes in patients of colorectal cancer at early age].
OBJECTIVE
To investigate the etiological role of function and construction alteration in mismatch repair genes MSH2 and MLH1 in the patients onset of colorectal cancers (CRC) at early ages.


METHODS
The genomic DNA was extracted from the tumor tissues and normal colon tissues during operation and subjected to analysis of microsatellite instability (MSI) in 42 Chinese patients aged less than 50 with CRC. Mutation screenings were performed with denaturing high-performance liquid chromatography (DHPLC) followed by DNA sequencing of DNA samples with variant peaks, and genomic deletion detection with quantitative multiplex PCR (Q-M-PCR) in the patients uncovered with MSI(+).


RESULTS
22 out of the 42 (52.4%) patients investigated were microsatellite instability positive (MSI(+)), 10/42 MSI(+)-H and 12/42 MSI(+)-L. 8 kinds of DNA germline alterations, 5 polymorphisms and 3 novel point mutations, were found in 9 patients with MSI(+). A large DNA (exon 1-6) deletion in MSH2 gene and a missense mutation Met242Ile in MLH1 gene were unveiled in CRC tissues of two patients with MSI(+)-H.


CONCLUSIONS
Mutations of mismatch repair genes are frequent in Chinese patients of CRC with onset at early ages.
Wang
Ya-ping
YP
Department of Molecular Biology, Jiangsu Institute of Cancer Research, Nanjing 210009, China.
Zhang
Jun-ni
JN
Li
Jin-tian
JT
Zhou
Jian-nong
JN
Zhang
Xiao-mei
XM
Zhu
Ming
M
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D002352:Carrier Proteins; D002851:Chromatography, High Pressure Liquid; D015179:Colorectal Neoplasms / Q000235:genetics*; D004268:DNA-Binding Proteins; D005260:Female; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein