OBJECTIVEThe tumor suppressor p53 pathway plays a crucial role in preventing carcinogenesis through its ability to impose cell cycle arrest and apoptosis following DNA damage or oncogene activation. Mouse double minute 2 (MDM2) gene is a key negative regulator of p53 pathway and overexpressed in many cancers as oncoprotein. We have previously shown that genetic polymorphisms in the MDM2 promoter (309T --> G) and p53 coding region (72Arg --> Pro) are associated with susceptibility to esophageal and lung cancers. This study investigated the associations between these polymorphisms in p53 and MDM2 and risk of the occurrence and progression of colorectal cancer.

METHODSGenotypes of 1000 Chinese colorectal cancer patients and 1300 controls were determined by PCR-based restriction fragment length polymorphism or tetra-primer amplification refractory mutation system-PCR. Associations with risk of colorectal cancer were estimated by unconditional logistic regression.

RESULTSAn increased colorectal cancer risk associated with the MDM2 GG [odds ratio (OR) = 2.06, 95% confidence interval (CI) = 1.62-2.62] or TG (OR = 1.31, 95% CI = 1.06-1.62) genotype was observed compared with the TT genotype. No association was found between p53 polymorphism and risk of the cancer, with the ORs being 0.87 (95% CI = 0.68-1.11) for the Pro/Pro and 0. 85 (95% CI = 0.70-1.04) for the Arg/Pro genotype compared with the Arg/Arg genotype. However, combined analysis of MDM2 and p53 polymorphisms showed that compared with subjects carrying both MDM2 TT and p53 Arg/Arg genotypes, the OR for subjects carrying both MDM2 GG and p53 Pro/Pro genotypes was 2.75 (95% CI = 1.60-4.70), significantly higher than that for subjects carrying both MDM2 TT and p53 Pro/Pro genotypes (OR = 1.09, 95% CI = 0.63-1.88).

CONCLUSIONThese results suggest that genetic polymorphism in MDM2 may be associated with susceptibility to colorectal cancer in a Chinese population.

Aged ; Asian Continental Ancestry Group ; genetics ; Colorectal Neoplasms ; genetics ; Confidence Intervals ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Humans ; Male ; Middle Aged ; Odds Ratio ; Polymorphism, Single Nucleotide ; Proto-Oncogene Proteins c-mdm2 ; genetics ; Risk Factors ; Tumor Suppressor Protein p53 ; genetics

OBJECTIVETo investigate the frequencies of alleles and the association with risk of esophageal cancer in a Mongolian population, and to compare the allele frequencies of these polymorphisms between the two populations and the susceptibility to esophageal cancer.

METHODSA case-control study was conducted, and 8 single nucleotide polymorphisms (SNP), including FAS - 670G/A, FAS - 1377G/A, FASL -844T/C, COX-2 - 1290A/G, COX-2 - 1195G/A, STK15 Phe31Ile, MMP-2 - 1306C/T and MMP -2 -735C/T, were detected by polymerase chain reaction-based restriction fragment length polymorphism assay (PCR-RFLP) in 188 esophageal cancer cases and 324 normal controls of Mongolian. The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression. The results were then compared with the reported data of the Han ethnic Chinese population.

RESULTSIn Mongolian, as compared with the STK15 31Ile/Ile genotype, the STK15 31Phe/Phe genotype carriers had an increased risk of esophageal cancer (adjusted OR = 2.20, 95% CI: 1.12-4.31), and the subjects with MMP-2 - 735TT genotype had an increased risk of esophageal cancer as compared with those with the MMP-2 - 735CC genotype (adjusted OR =4.82, 95% CI: 1.59 - 14.60). However, the rest of SNPs were not associated with the susceptibility to esophageal cancer. The allele frequencies of FASL - 844 T/C [0.264(171/648)/0.736 (477/648), 0.323(418/1296)/0.677(878/1296)], COX-2 - 1195G/A [0.431(279/648)/0.569(369/ 648), 0.492(1250/2540)/0.508(1290/2540)], MMP-2 - 1306C/T [0.869(563/648)/0.131(85/ 648), 0.835(1298/1554)/0.165(256/1554)] and MMP-2 - 735C/T [0.789(511/648)/0.211(137/ 648), 0.748(1163/1554)/0.252(391/1554)] were significantly different between the ethnic populations (chi2 = 7.03, 7.84, 3.94, 4.05, respectively, P <0.05).

CONCLUSIONThese findings suggested that STK15 Phe31Ile and MMP-2 -735C/T polymorphisms might be the genetic susceptibility factors for esophageal cancer in Mongolian and there should be some differences of genetic susceptibility to esophageal cancer in between Han ethnic Chinese and Mongolian population.

Adult ; Aged ; Asian Continental Ancestry Group ; genetics ; Aurora Kinase A ; Aurora Kinases ; Case-Control Studies ; Esophageal Neoplasms ; genetics ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Humans ; Male ; Matrix Metalloproteinase 2 ; genetics ; Middle Aged ; Polymorphism, Single Nucleotide ; Protein-Serine-Threonine Kinases ; genetics