ESR1 and breast cancer: We observed a statistically significant positive correlation between SNAI2 and ESR1 methylation in BC patients (Pearson r = 0.2480, p < 0.0001), especially in ERα‐positive (Pearson r = 0.4077, p < 0.0001) rather than ER‐negative BC patients (Pearson r = −0.05771, p = 0.4547) (Figure 1A‐C).