| Objective:Micro RNA(mi RNA),highly conserved small no-coding RNA with lengths of 22 nucleotides,regulates the translation of target m RNA at the post-transcriptional levels.It usually results in gene-silencing via translational repression or target degradation by base-pairing with complementary sequences of the 3’ untranslated region(3’UTR) in target m RNA.Mi RNA plays an important role in fundamental cell processes such as proliferation, differentiation,development, survival and apoptosis by regulating the expression of at least 30% of protein-coding genes.Increased evidences showed that mi RNA was aberrantly expressed in cancer cells, and it has been linked with the etiology and prognosis of many tumors. Single nucleotide polymorphism(SNP) is widely distributed in the entire human genome and contributes to the genetic variations between individuals in term of gene sequence. SNP can influence the complementarity between the mi RNA and its target m RNA so as to alter the expression of target genes.Several single nucleotide polymorphisms are considered to have significant impacts on susceptibility for carcinogenesis. However,only few of these studies focused on the relationship of SNP in the mi RNA binding sites and colon cancer risk. Previous studies have identified 12 cancer risk-associated SNPs located in mi RNA targeting sites, six SNPs with minor allele frequencies less than 5% were excluded based on our sequence data, and our collaborators had investigated the relationship of SET8(rs16917496) and colon cancer, so we performed the study for the five mi RNA binding site SNPs, located in the 3’UTR of KRT81(rs3660), RYR3(rs1044129), C14orf101(rs4901706), KIAA0423(rs1053667), and GOLGA7(rs11337) in colon cancer patients to assess their relationships with cancer risk. MMethods:1 Sample collection: Blood samples were collected at the Fourth Hospital of Hebei Medical University from 166 patients with colon cancer who underwent tumor resection in the Department of Sugery from July 2006 to September 2008. The patients’ clinical characteristics such as gender,age,et al were accurately recorded.Blood samples were also collected from 233 age-matched healthy controls without any cancer history at Fourth Hospital of Hebei Medical University from October 2011 to May 2012.2 DNA extraction, amplification and mi RNA binding site SNP screening: Genomic DNA was extracted immediately with a TIANamp Genomic DNA Kit and stored at 4?C. Polymerase chain reaction(PCR) was performed using a PCR Master Mix Kit according to manufactor’s instructions. The products were confirmed by agarose gel electrophoresis. The mi RNA binding site SNP, including KRT81(rs3660), RYR3(rs1044129), C14orf101(rs4901706), KIAA0423(rs1053667), and GOLGA7(rs11337) were genotyped using the Polymerase Chain Reaction- Ligase Detection Reaction(PCR-LDR) assay with the forward and reverse primers to amplify the DNA fragments flanking SNP based on the NCBI database.3 Statistical analysis:Student’s t-test was used to analysis quantitative data.The χ2 test was used to analyze dichotomous values, such as the presence or absence of an individual SNP in patients and healthy controls. The odds ratio(OR) and 95% confidence interval(95% CI) were calculated using an unconditional logistic regression model.All of the statistical analyses were performed using the SPSS 17.0 software package. P<0.05 was considered statistically significant.Results:1 For rs3660, the genotype distribution frequency between G/G and C/G+C/C was significant difference between colon cancer patients and healthy controls(OR: 1.583, 95%CI: 1.029-2.436, P=0.036). The G/G genotype of rs3660 was associated with a 1.583-fold increased risk when compared with that of the C/G+C/C genotype. As for rs1053667 in KIAA0423, the T/T genotype of rs1053667 was associated with a 3.077-fold increased risk when compared with C/T+C/C genotype(OR: 3.077,95%CI: 2.095-6.454,P=0.000).2 The genotype distribution frequency for each SNP(rs1044129 、rs4901706、rs11337) was showed no statistical difference between colon cancer patients and matched controls.3 No association exist for the genotype distribution of rs3660 and rs1053667 with clinical characteristics(Gender、Age、Tumor location 、Size of the tumor、Ducks stages)in colon cancer patients(P>0.05).Conclusions:1 For the SNP rs3660 of KRT81 and rs1053667 of KIAA0423, the frequency distribution for each SNP was significant difference between colon cancer patients and healthy controls. The SNP for rs3660 and rs1053667 were associated with the cancer risk for colon cancer.SNPs of micro RNA binding site are valuable biomarker to predict colon cancer risk.2 The different genotypes are not significantly correlated to the different clinical characteristics of colon cancer.3 SNP of micro RNA binding site are valuable biomarker to predict colon cancer risk. |
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