Figure 2. Correlation between CpG methylation and ESR1 expression levels. (A) An example- correlation between methylation level of cg03387103 (corresponding to LETM1) and ESR1 expression level in all breast cancer samples. (B) CpGs in ER binding peaks have larger negative correlations with ESR1 expression in their methylation levels. (C) Fraction of CpGs highly correlated with ESR1 expression. There is a higher fraction of anti-correlated CpGs in ERα binding sites compared with non-ERα binding sites at ± 0.4 SCC cutoff. (D) CpGs in ER binding peaks have higher average methylation levels in ER- than ER+ samples. Each point is a CpG. SCC: Spearman correlation coefficient.