ESR1 and breast cancer: The hierarchical clustering established with the most variant methylation scores observed in 5,492 promoters (SD>0.3) classified the 109 BC and 8 NB samples into clusters associated with different DNA methylation patterns (Fig. 4A) variably associated with ER and PR expression (p = 5.6×10−7 and p = 2.26×10−7), SBR grade, molecular subtype (p = 5×10−4), and TP53 status (p = 1.2×10−3) (Table S4A).