Correction Between HMLH1-93G/A Gene Polymorphism And Colorectal Cancer

Background and Aims:MLH1 is a critical member of MMR system,it plays an important in recognising and repairing mismatched base,and it is believed that the SNP of mismatched gene is helpful to the diagnosis of colorectal cancer. The aims were to explore the correlation between functional polymorphism of hMLH1 and the development and progression of colorectal cancer(CRC) in China.Methods:We carried out a case-control study, based on the population of colorectal cancer in China and healthy controls who had no tumor or inherited disease history. Genomic DNA was extracted from peripheral white blood cell from all subjects. The polymorphism was genotyped with TaqMan MGB probe method.Results:The frequency of hMLH1-93G/A genotype and allele were not significantly different between colorectal cancer patients and healthy controls (genotype P=0.219, allele P=0.879).The frequency of A/A genotype and A allele in C+D stage (181 patients in total) were higher than those in A+B stages(103 patients in total) (A allele:60.5% vs 48.1%, A/A genotype:39.8% vs 23.3%), and the differences were significant (genotype:% 2=8.360, P=0.015, allele:% 2=8.244, P=0.004,OR=1.655,95%CI=1.172-2.337).We also found that the A/A genotype and A genotype were more common in Patients with lymphatic metastasis than patients without lymphatic metastasis(genotype:x2=6.936,P=0.031,allele:x2=6.590, P=0.010, OR=0.642,95% CI= 0.458-0.642). We also observed that hMLHl expression in normal colorectal tissues was higher than the CRC patients(t-test, P=0,029), hMLH1 expression in colorectal cancer tissues with lymphatic metastasis was lower than patients without lymphatic metastasis (t test, P=0.001). hMLHl expression for the A-allele was lower than G-allele in CRC (t test, P=0.018), but there was no statistically significant difference of hMLH1 expression for the A-allele and the G-allele in normal controls.Conclusions:hMLH1-93G/A polymorphism is not associated with risk of developing colorectal cancer(CRC),but hMLH1-93A/A genotype and A allele are related to the progression of colorectal cancer.