[Hypermethylation of hMLH1 promoter in sporadic colorectal cancer].
To identify CpG island hypermethylation of 5'region of hMLH1 promotor and to explore its relationship to microsatellite instability(MSI)in sporadic colorectal carcinoma.



Forty-one pairs of tissue specimens (normal and cancer) were collected from 41 patients with colorectal cancer. Hypermethylation of hMLH1 promoter was detected by methylation specific PCR; the relationship between methylation and clinicopathological features was analyzed. Combined with BAT25 and BAT26, the MSI status was detected using an automated fluorescent DNA sequencer.



Hypermethylation of hMLH1 promoter was detected in 75.6 % (31/41) of samples. Mean age of unmethylation cases (49.2 y) was significantly younger than that of methylation cases (63.6 y) (P<0.05), but there were no differences between two groups in other clinicopathological features. MSI was detected in 43.9 % samples (18/41); hypermethylation of hMLH1 promoter was detected in 94.4 % (17/18) of MSI(+) samples, which was higher than that in MSI(-) samples (60.9 %,14/23, P<0.05).



Age-related hypermethylation is generally found in patients with sporadic colorectal cancers, which may cause MSI and might be the mechanism in the development of colorectal cancer of elderly people.
Song
Yong-mao
YM
The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China. zsym@mail.hz.zj.cn
Yuan
Ying
Y
Zheng
Shu
S
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002352:Carrier Proteins; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D018899:CpG Islands; D019175:DNA Methylation; D004260:DNA Repair; D005260:Female; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1