Genetic Polymorphisms of p53 Codon 72 and Bladder Cancer Susceptibility: A Hospital-Based Case–Control Study

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.

Association of P53 gene polymorphism with gastric cancer in Northern Iran as a high-risk region

Gastric cancer has the fourth highest morbidity rate of all cancers worldwide. Genetic factors including alterations in oncogenes and tumor suppressor genes serve an important role in gastric cancer development and progression. The P53 gene acts as a tumor suppressor gene by regulating the cell cycle, DNA transcription and repair, apoptosis, senescence and genome stability. In addition to somatic P53 mutations in cancer development, germline polymorphisms are also involved in different malignancies. The polymorphism of P53 at codon 72 (Arg72Pro) is established as a common variant that increases susceptibility to various cancers. The present case-control study was conducted to evaluate the possible association between this P53 polymorphism and gastric cancer in the Iranian population. A total of 59 patients with gastric cancer and 59 healthy controls were enrolled in the present study. Genomic DNA was extracted from peripheral blood mononuclear cells and genotype analysis was performed using a polymerase chain reaction-based restriction fragment length polymorphism assay. Genotype frequencies did not differ significantly between the patients and controls (P=0.4); the frequencies of the three genotypes Arg/Arg, Arg/Pro and Pro/Pro in gastric cancer patients were 28.8, 49.2 and 22.0%, and in controls were 37.3, 49.2 and 13.6%. Additionally, there were no differences in genotype frequencies based on tumor location, histological differentiation or tumor stage. Based on these findings, it may be concluded that the P53 codon 72 polymorphism does not contribute to gastric cancer susceptibility in Northern Iran.

Quantitative assessment of the association between TP53 Arg72Pro polymorphism and bladder cancer risk

Previous studies investigating the association between TP53 Arg72Pro polymorphism and bladder cancer risk reported controversial results. To quantify the strength of association between TP53 Arg72Pro polymorphism and bladder cancer risk, we performed this meta-analysis. We searched PubMed, Embase and Wangfang databases for studies relating the association between TP53 Arg72Pro polymorphism and bladder cancer risk. We used the pooled odds ratios (ORs) with their 95 % confidence intervals (95 % CIs) to assess the association. Finally, data were available from a total of 16 case-control studies including a total of 5, 545 subjects (2,345 cases and 3,200 controls). Meta-analysis of all 16 studies showed TP53 Arg72Pro polymorphism was not associated with bladder cancer risk (All P values were more than 0.10). Subgroup analyses by ethnicity showed that TP53 Arg72Pro polymorphism contributed to bladder cancer risk in East Asians in three genetic models (For Pro vs. Arg, Fixed-effects OR 1.18, 95 % CI 1.05-1.32; For ProPro vs. ArgArg, Fixed-effects OR 1.40, 95 % CI 1.11-1.77; For ProPro vs. ArgPro/ArgArg, Fixed-effects OR 1.32, 95 % CI 1.07-1.62). However, there was no significant association in Caucasians and the others (All P values were more than 0.05). Heterogeneity analyses suggested ethnicity was the major sources of heterogeneity. Thus, meta-analyses of available data suggest the Pro variant of TP53 Arg72Pro contributes to bladder cancer risk in East Asians. Besides, TP53 Arg72Pro polymorphism may have race-specific effects on bladder cancer risk and further studies are needed to elucidate this possible effect.

Association of p53 Arg72Pro polymorphism with bladder cancer: a meta-analysis

BACKGROUND

p53 tumor suppressor gene Arg72Pro polymorphism has been associated with bladder cancer. However, results were inconsistent. We performed this meta-analysis to estimate the association between p53 Arg72Pro polymorphism and bladder cancer.

METHODS

Electronic search of PubMed was conducted to select studies. Studies containing available genotype frequencies of Arg72Pro were chosen, and pooled odds ratio (OR) with 95% confidence interval (CI) was used to assess the association.

RESULTS

The final meta-analysis included 14 published studies with 2176 bladder cancer cases and 2798 controls. The results suggested that the variant genotype was associated with the bladder cancer risk (additive model: OR=1.72, 95% CI: 1.036-1.325, P=0.011; dominant model: OR=1.268, 95% CI: 1.003-1.602, P=0.047) in Asian subgroup. However, the association was not significant between this polymorphism and bladder cancer risk in Caucasian (additive model: OR=0.773, 95% CI: 0.564-1.059, P=0.109; dominant model: OR=0.685, 95% CI: 0.418-1.124, P=0.134).

CONCLUSION

This meta-analysis suggests that p53 Arg72Pro polymorphism is associated with increased risk of bladder cancer in Asians. To validate the association between this polymorphism and bladder cancer, further studies with larger participants worldwide are needed.

Association between p53 codon 72 genetic polymorphisms and tobacco use and lung cancer risk in a Chinese population

Genetic polymorphisms of p53 codon 72 are thought to have significant effects on the metabolism of environmental carcinogens and thus on lung cancer risk, but the reported results are not always consistent. The aim of this study is to investigate the relationship between p53 codon 72 genetic polymorphisms and tobacco use and lung cancer risk in a Chinese population. A population-based control study was conducted in 360 lung cancer patients and 360 cancer-free controls. The genotype of the p53 codon 72 was determined by using a polymerase chain reaction-restriction fragment length polymorphism assay. Patients with lung cancer had a significantly lower frequency of Pro/Pro genotype [odds ratio (OR) = 0.58, 95 % confidence interval (CI) = 0.40, 0.84; P = 0.004] and Pro allele (OR = 0.72, 95 % CI = 0.59, 0.89; P = 0.002) than controls. Patients with squamous cell carcinoma had also a significantly lower frequency of Pro/Pro genotype (OR = 0.45, 95 % CI = 0.25, 0.82; P = 0.009). In the analysis combining p53 codon 72 polymorphisms and smoking, smokers who had smoked for more than 30 pack-years had a significantly lower frequency of Pro/Pro genotype (OR = 0.52, 95 % CI = 0.30, 0.92; P = 0.03) compared with non-smokers. This study suggests that p53 codon 72 polymorphisms play a role in the development of lung cancer and modifies the risk for smoking-related lung cancer in a Chinese population.

Meta-analysis of the association between P53 codon 72 polymorphisms and gastric cancer

PURPOSE

This meta-analysis aims to examine whether the P53 codon 72 polymorphisms is associated with gastric cancer risk.

METHODS

Pooled odds ratios (ORs) were appropriately derived from random-effects models. Separate analyses were conducted on Asian and Caucasian populations. And a total of 21 studies were eligible (5,867 cases and 7,001 controls); 15 of them were conducted on Asians, others on Caucasians.

RESULTS

The combined results based on all studies showed that there was significant difference in genotype distribution between gastric cancer and non-cancer patients in the allele contrast (Pro vs. Arg); the codominant model (Pro/Pro vs. Arg/Arg) and the recessive model (Pro/Pro vs. Pro/Arg + Arg/Arg). When stratifying for race, patients with gastric cancer had a significantly higher frequency of Pro (OR = 1.136, 95% CI = 1.051-1.229), Pro/Pro (OR = 1.314, 95% CI = 1.110-1.555), Pro/Arg (OR = 1.099, 95% CI = 1.009-1.197), (Pro/Pro + Pro/Arg (OR = 1.153, 95% CI = 1.059-1.255) than non-cancer patients among Asians. There was statistically significant heterogeneity across all included studies with the Q statistic and study population may be the most important factor contributed to the heterogeneity.

CONCLUSIONS

In conclusion, the P53 codon 72 polymorphisms seems to be associated with gastric cancer risk and the analyses suggested that P53 codon 72 polymorphisms may be an important biomarker of gastric cancer susceptibility for Asians.

DNA repair gene XRCC3 T241M polymorphism and bladder cancer risk in a Chinese population

The X-ray repair cross-complementing group 3 (XRCC3), one of the DNA repair genes, was suggested to play an imperative role in the development of carcinogenesis. The objective of this study was to evaluate the role of the XRCC3 T241M polymorphism in bladder cancer susceptibility in a Chinese population. We genotyped 150 bladder cancer cases and 150 healthy controls who had been frequency matched to cases by age and sex. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism analysis. A significant association was found between smoker and bladder cancer [odds ratio (OR)=1.97, 95% confidence interval (CI)=1.24-3.13, p=0.004]. The XRCC3 241MM genotype was more frequent in the bladder cancer group than in the healthy controls group (OR=3.22, 95% CI=1.14-9.11, p=0.03). There were no significant associations between any genotypes and the stage, grade, and histological type of bladder cancer. Our study suggested an increased risk role of XRCC3 241MM genotype in bladder cancer susceptibility in a Chinese population.