The following criteria were used for the literature selection for the further meta-analysis:

1. Studies concerning the association of TP53 codon 72 polymorphism with breast carcinoma;   2. Case–control or cohort studies;   3. Papers presenting the breast cancer diagnoses and the sources of cases and controls;   4. Articles offering the size of the sample, odds ratios (ORs) and their 95% confidence intervals (CIs) or the information that can help infer the results;   5. The number of individuals homozygous for arginine (Arg/Arg), proline (Pro/Pro) and heterozygous (Pro/Arg) in KU55933 mouse breast cancer cases and controls should be offered;   6. The methods of data collection and analysis should be statistically acceptable.   Accordingly, the following exclusion criteria were also used: 1. The design and the definition of the experiments were obviously different from those of the selected papers.   2. The source of cases and controls and other essential information were not offered;   3. The genetic distribution of the control group was inconsistent with Hardy-Weinberg equilibrium (HWE).   4. Reviews and duplicated publications.   After searching, we reviewed all papers in accordance with the criteria defined above for further analysis.

Data extraction Data were carefully extracted from all eligible publications independently by two of the authors according to the inclusion criteria mentioned GSK461364 concentration above. For conflicting evaluations, an agreement was CHIR98014 purchase reached following a discussion. If a consensus could not be reached, another author was consulted to resolve the Acyl CoA dehydrogenase dispute and then a final decision was made by the majority of the votes. The extracted information was entered into a database. For data not provided in the main text, the relevant information was obtained by contacting corresponding authors as possible as we could. Statistical analysis The odds ratio (OR) of TP53 codon 72 polymorphisms and breast cancer risk was estimated for each study. The pooled ORs were performed for additive model (Arg/Arg vs Pro/Pro), dominant model (Arg/Arg+Arg/Pro versus Pro/Pro) and recessive model (Arg/Arg versus Arg/Pro+Pro/Pro), respectively. For detection of

any possible sample size biases, the OR and its 95% confidence interval (CI) to each study was plotted against the number of participants respectively. A Chi-square based Q statistic test was performed to assess heterogeneity. If the result of the heterogeneity test was P > 0.05, ORs were pooled according to the fixed-effect model (Mantel-Haenszel), Otherwise, the random-effect model (DerSimonian and laird) was used. The significance of the pooled ORs was determined by Z-test. The HWE was assessed via Fisher’s exact test. Publication bias was assessed by visual inspection of funnel plots[23], in which the standard error of log (OR) of each study was plotted against its log (OR). An asymmetric plot indicates a possible publication bias.