MTHFR and myeloid sarcoma: Selected articles for meta-analysis had the following features: evaluation of the relationship between MTHFR gene and MS, number of subjects in case and control groups, access to distribution of genotypes and alleles in case and control groups, considering 95% confidence interval (CI) to estimate odds ratio (OR), original research articles, randomized and controlled articles, and considering gene polymorphism as the main independent variable.