ESR1 and neoplasm: Differential analysis of tumor versus healthy biopsies highlighted 166 candidate genes with different DNA methylation levels in their promoters (Figures 2D and 2E; Table S6), which included the tumor-specific hypomethylated EGFL8 promoter as well as hypermethylated promoters of ESR1, PTGIS, and GATA3 (Figure 2E).