Research Report
Copyright ©2014 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 28, 2014; 20(48): 18338-18345
Published online Dec 28, 2014. doi: 10.3748/wjg.v20.i48.18338
Comparative study of mutations in SNP loci of K-RAS, hMLH1 and hMSH2 genes in neoplastic intestinal polyps and colorectal cancer
Zhi-Hui Yan, Li-Hong Cui, Xiao-Hui Wang, Chao Li, Xing He
Zhi-Hui Yan, Li-Hong Cui, Xiao-Hui Wang, Chao Li, Xing He, Department of Gastroenterology, Navy General Hospital of PLA, Beijing 100048, China
Author contributions: Yan ZH and Cui LH contributed equally to this work; all authors contributed to the manuscript.
Supported by Capital Public Health Project Cultivation Program, No. Z111107067311051
Correspondence to: Li-Hong Cui, PhD,MD, Department of Gastroenterology, Navy General Hospital of PLA, 6 Fucheng Road, Beijing 100048, China. luckycui861@sina.com
Telephone: +86-10-66957541 Fax: +86-10-68780570
Received: June 8, 2014
Revised: July 12, 2014
Accepted: August 13, 2014
Published online: December 28, 2014
Processing time: 211 Days and 21.2 Hours
Abstract

AIM: 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 (χ2 = 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 (χ2 = 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.

CONCLUSION: There may be important clinical significance and relevance between neoplastic intestinal polyps and colorectal cancer in terms of the mechanisms involved in the pathogenesis.

Keywords: Neoplastic intestinal polyp; Colorectal cancer; Single nucleotide polymorphisms; K-RAS; hMLH1; hMSH2

Core tip: This study selects the blood and tissue samples of neoplastic polyps, colorectal cancer and normal tissues for related gene sequencing. By comparing the differences in SNPs, the genetics and pathogenesis of colorectal cancer are analyzed.