The gene expression and promoter methylation level of the STAT3 gene in MS and control groups. a STAT3 gene expression in patients compared with control subjects. Mean fold change in MS patients and control group was 1.000 ± 0.024 and 0.250 ± 0.014, respectively (P-value < 0.0001). b The methylation level (% M) of STAT3 in MS patients compared with control group. The red dots are individual values, and boxes are the mean methylation for patient (30.56 ± 1.317) and control groups (59.08 ± 1.986). c, d Correlation analysis between methylation status and gene expression level of STAT3 in patients (R2 = 0.8967, P-value < 0.0001, regression analysis) and control (R2 = 0.9256, P-value < 0.0001, regression analysis) group. e Negative and positive controls for methylation assays. 5-Azacytidine and DNA sample treated with SssI methyltransferase were used as negative and positive controls, respectively . (*P-value < 0.05, **P-value < 0.01, ***P-value < 0.001, ****P-value < 0.0001).