Fig. 1

The sequence of the CpG island in the ESR1 gene. A ESR1 promoter region scheme in chromosome 6 (Chr6). The 300-kilobases ESR1 gene contains seven promoters (color boxes) utilized in a tissue-specific manner and eight exons (only exon 1 is shown). B Assessed DNA sequence in the proximal promoter. A 151-bp sequence (blue box) located in the A promoter between the transcription start site (+ 1) and the ATG codon (+ 235) was evaluated. Underlined sequences corresponded to the primers used for methylation analysis. Nomenclature and numbering are based on previous reports [21, 54]. C Methylation-specific PCR analysis of ESR1. Electrophoretic profile of methylated (M) (lanes 2 and 4) and unmethylated (U) (lanes 3 and 5) samples from positive (lanes 2 and 3) and negative (lanes 4 and 5) controls using genomic DNA from patients with fibroadenoma. 50-bp DNA Ladder (lane 1). Arrowhead indicates the amplicon size. Genomic coordinates of the 151-bp island in the ESR1 gene: GRCh38: Chr6: 151,500,579–151,500,730