Germline mutation analysis of hPMS2 gene in Chinese families with hereditary nonpolyposis colorectal cancer.
OBJECTIVE
To study the germline mutation of hPMS2 gene in 26 unrelated Chinese hereditary nonpolyposis colorectal cancer (HNPCC) probands and to fulfill the screening strategy for HNPCC in Chinese.


METHODS
Genomic DNA was extracted from the peripheral blood. To avoid the interference of pseudogene in detection of the remaining 11 exons (exon 1-5, 9, 11-15), long-range polymerase chain reaction (PCR) was conducted to amplify the complete coding region of hPMS2 gene firstly. Then 1/8 of the PCR products were used as template to amplify the individual exon respectively and DNA sequencing was done. Direct DNA sequencing of the conventional PCR products of exon 6, 7, 8 and 10 of hPMS2 gene was performed. The same analysis was made in 130 healthy persons without family histories of HNPCC to further investigate the pathological effects of the detected missense mutation.


RESULTS
One HNPCC proband fulfilled Bethesda guidelines and was found to carry the germline mutation of hPMS2 gene, which has not been reported in Chinese HNPCC families. It was a missense mutation at c.1532C>T of exon 11. It was detected in three controls as well with an occurrence rate of 2.3% (3/130). Since it could not be found in the PMS2-single nucleotide polymorphism (SNP) database, this missense mutation is a new SNP unreported up to date. Meanwhile, 260 reported SNPs of hPMS2 gene were detected in the 26 HNPCC probands. The 2nd and 5th exons were probably the hot SNP regions of hPMS2 gene in Chinese HNPCC families involving 53.1% of all reported SNP.


CONCLUSIONS
The germline mutation of hPMS2 gene may be rare in Chinese HNPCC families. The 2nd and 5th exons are hot SNP regions of hPMS2 gene.
Sheng
Xia
X
Department of Pathology, Shanghai Cancer Center, Fudan University, Shanghai 200032, China.
Zhou
Heng-Hua
HH
Zhou
Xiao-Yan
XY
Du
Xiang
X
Zhang
Tai-Ming
TM
Cai
San-Jun
SJ
Sheng
Wei-Qi
WQ
Shi
Da-Ren
DR
D000251:Adenosine Triphosphatases / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000208:ethnology / Q000235:genetics*; D004252:DNA Mutational Analysis; D045643:DNA Repair Enzymes / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005091:Exons; D020022:Genetic Predisposition to Disease; D018095:Germ-Line Mutation; D040941:Heredity; D006801:Humans; D000070976:Mismatch Repair Endonuclease PMS2; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide
D004268:DNA-Binding Proteins; D000251:Adenosine Triphosphatases; C094934:PMS2 protein, human; D000070976:Mismatch Repair Endonuclease PMS2; D045643:DNA Repair Enzymes