Influence of MIF polymorphisms on CpG island hyper-methylation of CDKN2A in the patients with ulcerative colitis.

BACKGROUND: CDKN2A hypermethylation is among the major events associated with carcinogenesis and is also observed in non-neoplastic colonic mucosa in patients with ulcerative colitis (UC). Macrophage migration inhibitory factor (MIF) plays a crucial role in promoting gastrointestinal inflammation characteristic of UC. The aim of this study is to explore associations between CDKN2A methylation status and MIF polymorphisms (rs755622 and rs5844572). METHODS: One hundred and fifty-nine patients diagnosed with UC were enrolled in this study. The methylation status of p14ARF and p16INK4a was determined by MSP; MIF genotypes were identified by PCR-SSCP. RESULTS: We found no differences with respect to mean age, gender, clinical type (chronic continuous or relapse/remitting), or extent of disease among the patients with methylated and unmethylated p14ARF or p16INK4a. Carrying the rs755622 C allele indicated a significantly higher risk for p14ARF methylation (odds ratio (OR), 2.16; 95% confidence interval (CI), 1.08-4.32; p = 0.030); similarly, carrying the rs5844572 7-repeat allele indicated a significantly higher risk for p16INK4a methylation (OR, 2.57; 95% CI, 1.26-5.24; p = 0.0094) after an adjusted regression analysis. The carriers of the rs755662 C allele or the rs5844572 7-repeat allele were both at a significantly higher risk for methylation of both p14ARF and p16INK4a when compared to the cohort in which neither of the genes were methylated (OR, 2.70; 95% CI, 1.22-6.01; p = 0.015 and OR, 2.87; 95% CI, 1.25-6.62; p = 0.013, respectively). Additionally, carrying rs755622 C allele was significantly associated with CIHM in chronic continuous of clinical type and total colitis (OR, 25.9; 95% CI, 2.55-262.6; p = 0.0059 and OR, 4.38; 95% CI, 1.12-17.2; p = 0.034, respectively), and carrying 7-repeat allele of rs5844572 was significantly associated in chronic continuous type (OR, 14.5; 95%CI, 1.46-144.3; p = 0.022). CONCLUSIONS: Taken together, our findings suggest that MIF genotypes associated with inflammation may also be involved in promoting carcinogenesis via CDKN2A hypermethylation in patients diagnosed with UC.

MAFK Polymorphisms Located in 3'-UTR are Associated with Severity of Atrophy and CDKN2A Methylation Status in the Gastric Mucosa.

Objective: This study aimed to clarify the association of MAFK polymorphisms (rs4268033, rs3735656, and rs10226620) with the degree of gastric mucosal atrophy and CDKN2A CpG methylation status. Methods: A total of 491 subjects were enrolled in this study. Genotypes and methylation status were determined by polymerase chain reaction (PCR)-single-stranded conformation polymorphism and methylation-specific PCR (Fujita Health University, HM18-094). Methods: A total of 491 subjects were enrolled in this study. Genotypes and methylation status were determined by polymerase chain reaction (PCR)-single-stranded conformation polymorphism and methylation-specific PCR (Fujita Health University, HM18-094). Results: Either rs3735656 or rs10226620, located in the 3'-UTR of MAFK, was significantly associated with the severity of gastric mucosal atrophy using a dominant genetic model (odds ratio [OR], 2.10; p = 0.0012, and OR, 1.98; p = 0.0027, respectively). However, using a recessive genetic model, no significant association was found between three polymorphisms and gastric mucosal atrophy. The serum pepsinogen I/II ratio was significantly lower in subjects with minor alleles of rs3735656 and rs10226620 than in subjects with the wild homozygous allele (p = 0.018 and 0.013, respectively). In a subgroup including 400 of the 491 subjects, the CpG of p14ARF and p16 INK4a were methylated in 132 and 112 subjects, respectively. Fifty subjects had both CpG methylations and 206 subjects had neither methylation. When comparing the groups with both and neither methylations, there were no significant associations between three polymorphisms and CDKN2A methylation using a dominant genetic model. However, all polymorphisms investigated in this study (rs4268033, rs3735656, and rs10226620) were significantly associated with CDKN2A methylation in a recessive genetic model (OR, 3.58; p = 0.0071, OR, 4.49; p = 0.0004, and OR, 3.45; p = 0.0027, respectively). Conclusions: Our results indicate that carrying the minor allele of the MAFK polymorphisms, particularly when they are located in the 3'-UTR, has a high risk for the severity of gastric mucosal atrophy; furthermore, CDKN2A CpG methylation may develop in subjects with homozygous minor allele of these polymorphisms.