title: Comparative study of mutations in SNP loci of K-RAS, hMLH1 and hMSH2 genes in neoplastic intestinal polyps and colorectal cancer.
abstract: OBJECTIVE
  To clarify the molecular mechanism involved in pathogenesis of colorectal cancer as well as clinical significance of genetic analysis of histological samples.
  
  
  METHODS
  A total of 480 blood and tissue specimens were collected in our hospital from January 2011 to October 2012. In the observation group, there were 120 blood specimens and 120 intestinal tract tissue specimens collected from patients with neoplastic intestinal polyps. In the control group I there were 80 blood specimens and 80 intestinal tract tissue specimens collected from patients with colorectal cancer. In the control group II there were 40 blood specimens and 40 intestinal tract tissue specimens collected from healthy individuals. The gene segments were amplified using PCR and DNA gel electrophoresis along with DNA sequence analysis were employed for the detection of the following single nucleotide polymorphisms (SNPs): K-RAS codons 12 and 13; hMLH1 (human mutS homolog 1) gene missense mutation at Va1384Asp; hMSH2 (human mutS homolog 2) gene missense mutation at 2783C/A.
  
  
  RESULTS
  The mutation rate of the SNP at Va1384Asp locus of the hMLH1 gene from blood and tissue specimens in the observation group showed no statistical difference from those in the control group I. The mutation rates of SNPs in codons 12 and 13 of K-RAS and at 2783C/A locus of the hMSH2 gene were significantly lower in the observation group than in the control group I (χ(2) = 15.476, 29.670, 10.811, 16.618, 33.538, 7.898, P < 0.05). The mutation rate of SNP at Va1384Asp locus of the hMLH1 gene was significantly higher in the observation group when compared to the control group II (χ(2) = 10.486, 4.876, P < 0.05). The mutation rates of SNPs in codons 12 and 13 of K-RAS and at 2783C/A locus of the hMSH2 gene did not show any statistical difference from those in the control group II.
  
  
  CONCLUSIONS
  There may be important clinical significance and relevance between neoplastic intestinal polyps and colorectal cancer in terms of the mechanisms involved in the pathogenesis.
authors.affiliation: Zhi-Hui Yan, Li-Hong Cui, Xiao-Hui Wang, Chao Li, Xing He, Department of Gastroenterology, Navy General Hospital of PLA, Beijing 100048, China.
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Yan
authors.affiliation: Zhi-Hui Yan, Li-Hong Cui, Xiao-Hui Wang, Chao Li, Xing He, Department of Gastroenterology, Navy General Hospital of PLA, Beijing 100048, China.
authors.forename: Li-Hong
authors.initials: LH
authors.lastname: Cui
authors.affiliation: Zhi-Hui Yan, Li-Hong Cui, Xiao-Hui Wang, Chao Li, Xing He, Department of Gastroenterology, Navy General Hospital of PLA, Beijing 100048, China.
authors.forename: Xiao-Hui
authors.initials: XH
authors.lastname: Wang
authors.affiliation: Zhi-Hui Yan, Li-Hong Cui, Xiao-Hui Wang, Chao Li, Xing He, Department of Gastroenterology, Navy General Hospital of PLA, Beijing 100048, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: Zhi-Hui Yan, Li-Hong Cui, Xiao-Hui Wang, Chao Li, Xing He, Department of Gastroenterology, Navy General Hospital of PLA, Beijing 100048, China.
authors.forename: Xing
authors.initials: X
authors.lastname: He
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003062:Codon; D003111:Colonic Polyps / Q000235:genetics* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics*; D020125:Mutation, Missense; D009687:Nuclear Proteins / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D055815:Young Adult; D018631:ras Proteins / Q000235:genetics*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D003062:Codon; C117307:KRAS protein, human; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins
keywords: Colorectal cancer; K-RAS; Neoplastic intestinal polyp; Single nucleotide polymorphisms; hMLH1; hMSH2