By purifying ER-associated DNA (i.e. the genomic binding sites) by amethod called chromatin immunoprecipitation (ChIP) and identifying the associated DNAby tiling microarrays and subsequently by high-throughput DNA sequencing, unknown ERbinding sites were identified from breast cancer cell line models (26, 27, 28, 29). The gene discussed is ESR1; the disease is breast carcinoma.