The MDM2 SNP309T>G polymorphism increases bladder cancer risk among Caucasians: a meta-analysis

MDM2 promoter del1518 polymorphism and cancer risk: evidence from 22,931 subjects

Studies have shown that single-nucleotide polymorphisms in MDM2 gene may play important roles in the development of malignant tumor. The association of del1518 polymorphism (rs3730485) in the MDM2 promoter with cancer susceptibility has been extensively studied; however, the results are contradictory. To quantify the association between this polymorphism and overall cancer risk, we conducted a meta-analysis with 12,905 cases and 10,026 controls from 16 eligible studies retrieved from PubMed, Embase, and Chinese Biomedical (CBM) databases. We assessed the strength of the connection using odds ratios (ORs) and 95% confidence intervals (CIs). In summary, no significant associations were discovered between the del1518 polymorphism and overall cancer risk (Del/Del vs Ins/Ins: OR =1.01, 95% CI =0.90-1.14; Ins/Del vs Ins/Ins: OR =1.03, 95% CI =0.96-1.12; recessive model: OR =0.98, 95% CI =0.90-1.07; dominant model: OR =1.03, 95% CI =0.94-1.12; and Del vs Ins: OR =1.01, 95% CI =0.94-1.07). In the stratified analysis by source of control, quality score, cancer type, and ethnicity, no significant associations were found. Despite some limitations, the current meta-analysis provides solid statistical evidence of lacking association between the MDM2 del1518 polymorphism and cancer risk.

Murine Double Minute 2 SNP T309G Polymorphism and Urinary Tract Cancer Risk: A Meta-Analysis

Urinary tract cancer is a common cause of cancer-related death. The etiology and pathogenesis of urinary tract cancer remain unclear, with genetic and epigenetic factors playing an important role. Studies of the polymorphism of murine double minute 2 (MDM2) have shown inconclusive trends in the risk of urinary tract cancer.To clarify this inconsistency, we conducted updated meta-analyses to evaluate the role of MDM2 T309G polymorphism in urinary tract cancer susceptibility.Data sources were Pubmed (1966-May 2015), Chinese biomedicine literature database (1978-May 2015), and hand searching of the reference lists of included studies:(1) research categories case-control study or a nested case-control study; (2) information evaluating the association between the MDM2 SNP309 and urinary tract cancer risk; (3) studies with sufficient data to perform a meta-analysis.It included the use of odds ratios (ORs) to assess the strength of the association, and 95% confidence intervals (CIs) give a sense of the precision of the estimate. We used I for the assessment of between-study heterogeneity, and publication bias was assessed using the funnel plot and the Egger test. Statistical analyses were performed by Review Manage, version 5.0 and Stata 11.0.A total of 18 studies met the eligibility criteria and were included in our analyses. Overall, there was no statistical association between MDM2 SNP309 and prostate cancer risk for the allele contrast, the GG genotype, the recessive genetic model, the dominant genetic model, and prostate cancer risk in all subjects (OR = 0.96, 95% CI 0.87-1.05, P = 0.36; OR = 0.93, 95% CI 0.75-1.15, P = 0.50; OR = 1.00, 95% CI 0.87-1.15, P = 0.99; OR = 0.93, 95% CI 0.80-1.07, P = 0.30), and between MDM2 SNP309 and bladder cancer risk (the allele contrast: OR = 1.06, 95% CI 0.89-1.27, P = 0.50; the GG genotype: OR = 1.12, 95% CI 0.79-1.61, P = 0.52; the dominant genetic model: OR = 1.03, 95% CI 0.83-1.28, P = 0.78; the recessive genetic model: OR = 1.12, 95% CI 0.84-1.49, P = 0.45). However, there was positive association between MDM2 SNP309 and kidney cancer risk for the allele contrast (OR = 1.24, 95% CI 1.05-1.46, P = 0.01), the GG genotype (OR = 1.57, 95% CI 1.11-2.20, P = 0.01), dominant model contrast (OR = 1.30, 95% CI 1.00-1.68, P = 0.05), the recessive genetic model (OR = 1.37, 95% CI 1.02-1.83, P = 0.04).First, only the data of published studies were included in this meta-analysis. Unpublished studies tend to show more negative results; therefore, publication bias may be present. Second, because of the lack of the original data, we did not perform stratification analysis by age, hormone levels, dietary habit, or other variables. This might have caused confounding bias. Third, because the number of studies was relatively small for kidney cancer, the results might not have enough statistical power for us to investigate the association of the polymorphism with kidney cancer susceptibility, and we could not perform subgroup analyses. Finally, there were no studies about Africans in this meta-analysis.In summary, the results of our meta-analysis suggest an increased risk role of the MDM2 SNP T309G in renal cancer. However, there was no association between the MDM2 SNP T309G and prostate cancer risk or between the MDM2 SNP T309G and bladder cancer risk. Moreover, well-designed studies should estimate different ethnicities, degree of malignancy and clinical progression on the association between MDM2 SNP309 and urinary cancer risk in the future.

Association between MDM2 SNP309 T>G polymorphism and the risk of bladder cancer: new data in a Chinese population and an updated meta-analysis

Objective

Human murine double minute 2 protein (MDM2) is mainly a negative regulator of p53 tumor suppressor pathway. We aimed to investigate the association between MDM2 SNP309 polymorphism and bladder cancer risk.

Methods

A total of 535 bladder cancer patients and 649 health controls were recruited for our study. MDM2 SNP309 T>G polymorphism was genotyped by polymerase chain reaction-ligase detection reaction method. Logistic regression was used to analyze the relationship between the genotype and susceptibility of bladder cancer. Kaplan–Meier estimates and log-rank test were obtained to analyze the association between the genotype and risk of recrudesce in nonmuscle-invasive bladder cancer patients. A multivariable Cox proportional hazards model was fitted to identify independent prognostic factors. To further investigate the association, we conducted a meta-analysis including six studies.

Results

The frequency of the MDM2 SNP309 T>G polymorphism showed no significant difference between cases and controls (all P>0.05). In the stratification analysis, the results showed that G allele carriers were prone to have a significant decrease in risk of low-grade bladder cancer (adjusted odds ratio: 0.613, 95% confidence interval: 0.427–0.881), and G variant was associated with a significantly reduced risk of recurrence in nonmuscle-invasive bladder cancer patients with or without chemotherapy (P<0.05). The results of the meta-analysis showed that G allele and GG genotype of MDM2 SNP309 polymorphism were significantly associated with increased risk of bladder cancer in Caucasians (both P<0.05), and no association was observed in total populations and Asians (P>0.05).

Conclusion

MDM2 SNP309 T>G polymorphism has no influence on bladder cancer risk in Asians, but this single nucleotide polymorphism may be associated with genetic susceptibility of bladder cancer among Caucasians.

Association between interleukin-22 genetic polymorphisms and bladder cancer risk

OBJECTIVE

The cytokine interleukin-22 (IL-22), which is produced by T cells and natural killer cells, is associated with tumorigenesis and tumor progression in cancers. However, the role of IL-22 in bladder cancer has not been investigated.

MATERIALS AND METHODS

A prospective hospital-based case-control study comprising 210 patients with pathologically proven bladder cancer and 210 age- and gender-matched healthy controls was conducted. The genotypes of 3 common polymorphisms (-429 C/T, +1046 T/A and +1995 A/C) of the IL-22 gene were determined with fluorogenic 5' exonuclease assays.

RESULTS

Patients with bladder cancer had a significantly higher frequency of the IL-22 -429 TT genotype [odds ratio (OR)=2.04, 95% confidence interval (CI)=1.19, 3.49; p=0.009] and -429 T allele (OR=1.42, 95% CI=1.08, 1.87; p=0.01) than the healthy controls. These findings were still significant after a Bonferroni correction. When stratifying according to the stage of bladder cancer, we found that patients with superficial bladder cancer had a significantly lower frequency of the IL-22 -429 TT genotype (OR=0.48, 95% CI=0.23, 0.98; p=0.04). When stratifying according to the grade and histological type of bladder cancer, we found no statistical association. The IL-22 +1046 T/A and IL-22 +1995 A/C gene polymorphisms were not associated with the risk of bladder cancer.

CONCLUSION

To the authors' knowledge, this is the first report documenting that the IL-22 -429 C/T gene polymorphism is associated with bladder cancer risk. Additional studies are required to confirm this finding.