Association between MDM2-SNP309 and p53R72P polymorphisms and the risk of bladder cancer in the Mongolian population

Association of Murine Double Minute 2 polymorphisms with gastric cancer: A systematic review with meta-analysis

Gastric cancer (GC) is the 5th most common type of cancer, with the 3rd highest mortality rate worldwide in both sexes. Murine double minute 2 (MDM2) protein is the major negative regulator of p53, and genetic polymorphisms in this gene have shown to be associated with several types of cancer. In the present study, a literature search was performed using PubMed and Scopus with the following key word combinations 'gastric cancer AND polymorphism AND MDM2'. Studies were carefully revised according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify eligible studies that matched the inclusion criteria. Statistical analysis was performed to assess the association between the different genetic polymorphisms and GC risk, by calculating the odds ratios (OR) and the confidence intervals (CI), with a 5% level of significance. A total of 11 manuscripts studied MDM2 polymorphisms in GC: rs937283 (n=1), rs3730485 (n=1) and rs2279744 (n=9). Both the rs937283 and rs3730485 reports showed an association with GC; however, there was only one study on each of these polymorphisms in the literature. A meta-analysis was performed for the rs2279744 polymorphism, of which studies showed a positive association between the G allele and risk of GC, either in the dominant model (OR=1.46; 95% CI 1.21-1.75; P<0.001) or recessive model (OR 1.65; 95% CI 1.45-1.87; P<0.001). In conclusion, genetic polymorphisms in MDM2 seemed to be associated with an increased risk of GC development, nevertheless, the number of studies were relatively low and the studied populations were primarily Chinese. The present meta-analysis emphasizes the need for additional studies in other populations to corroborate the association of these polymorphisms with GC.

TP53 codon 72 Polymorphism and bladder cancer risk: a meta-analysis and emphasis on the role of tumor or smoking status

Background: Various studies had explored the relationship between TP53 codon 72 polymorphisms and the risk of bladder cancer (BC). However, their results remained inconsistent and the definite role of smoking or tumor status associated with this polymorphism in BC cases was seldom involved. Hence, this meta-analysis was to disclose such associations. Methods: Systematical and comprehensive retrieval of online databases PubMed, PMC, EMBASE and Web of Science were conducted to obtain eligible studies, up to May 30th, 2018. Pooled odds ratios (ORs) with 95% confidence intervals (CI) were utilized to assess the associations between TP53 codon 72 polymorphisms and BC susceptibilities under five genetic comparison models. Results: Ultimately, this meta-analysis enrolled 22 applicable studies with 3,791 BC cases and 4,917 controls. Our results suggested that the variant genotypes were associated with BC risk in Asian subgroup (allele model: OR=1.19, 95% CI=1.04-1.34; dominant model: OR=1.27, 95% CI=1.06-1.52; homozygote model: OR=1.36, 95% CI=1.03-1.80), while negative outcomes were presented in Caucasians. In the relationship between TP53 codon 72 polymorphisms and BC tumor stage in Asian group, positive results were presented in allele model: OR=1.68, 95% CI=1.04-2.72; dominant model: OR=2.46, 95% CI=1.08-5.61; heterozygous model: OR=2.32, 95% CI=1.04-5.14; homozygote model: OR=2.66, 95% CI=1.04-6.81. However, no evidence was revealed between this polymorphism and BC tumor grade. Besides, significant associations were displayed between TP53 codon 72 polymorphism and smoking status (allele model: OR=1.40, 95% CI=1.06-1.84; dominant model OR=1.72, 95% CI=1.18-2.50; heterozygous model: OR=1.77, 95% CI=1.19-2.64). Conclusion: Taken together, our results shed light on that TP53 codon 72 polymorphism was significantly associated with the susceptibility to BC in Asians. In addition, positive associations were also revealed between this polymorphism and tumor stage/smoking status in BC cases.

The frequency of TP53 R72P and MDM2 309T>G polymorphisms in Iranian infertile men with spermatogenetic failure: A case-control study

BACKGROUND

Tumor protein p53 (TP53) is a tumor suppressor transcriptional regulator protein which plays a critical role in the spermatogenesis. One of the most important regulators of p53 is Murine double minute 2 (MDM2), which acts as a negative regulator of the p53 pathway. Based on the key role of p53 and MDM2 in germ cell apoptosis, polymorphisms that cause a change in their function might affect germ cell apoptosis and the risk of male infertility.

OBJECTIVE

This study was designed to examine associations of TP53 72 Arg>Pro (rs1042522), and MDM2 309 T>G (rs937283) polymorphisms with spermatogenetic failure in Iranian population.

MATERIALS AND METHODS

A case-control study was conducted with 150 nonobstructive azoospermia or severe oligozoospermia and 150 fertile controls. The two polymorphisms, 72 Arg>Pro in TP53 and 309 T>G in MDM2, were genotyped using PCR-RFLP and ARMS-PCR respectively.

RESULTS

Our analyses revealed that the allele and genotype frequencies of the TP53 R72P polymorphism were not significantly different between the cases and controls (p=0.41, p=0.40 respectively). Also, no significant differences were found in the allelic (p=0.46) and genotypic (p=0.78) distribution of MDM2 309 T>G polymorphism between patients and controls.

CONCLUSION

The results of this study indicate that polymorphisms of TP53 and MDM2 genes are unlikely to contribute to the pathogenesis of male infertility with spermatogenetic failure.