2.4 Statistical analyses
Statistical analyses were performed with IBM SPSS Statistics 25.0 software (SPSS Inc. Headquarters, Chicago, IL, USA). Deviations from the Hardy-Weinberg (H-W) equilibrium of the MTHFR C677T/A1298C genotypes and the associations between categorical variables were tested using the chi-square test. EFS and OS were analyzed according to the Kaplan-Meier (K-M) method using the patient follow-up; differences were compared using the log-rank (Mantel Cox) test. The K-M survival curves were plotted using GraphPad Prism 8.0 (GraphPad Software, San Diego, CA, USA). P -values < 0.05 were considered significant. All data in our study have been recorded at SYSUCC for future reference (RDDA2020001559, https://www.researchdata.org.cn).