A carrier-assisted ChIP-seq method for Estrogen Receptor-chromatin interactions from breast cancer core needle biopsy samples. A carrier-assisted ChIP-seq method for Estrogen Receptor-chromatin interactions from breast cancer core needle biopsy samples

The Estrogen Receptor alpha (ERa) is the key transcriptional regulator in luminal breast cancer and the main target for adjuvant treatment. Luminal gene signatures are dictated by the transcriptional capacities of ERa, which are a direct consequence of the receptors binding preference at specific sites on the chromatin. The identification of ERa binding signatures on a genome-wide level has greatly enhanced our understanding of Estrogen Receptor biology in cell lines, but the technique has its limitations with respect its applicability in limit amounts of tumor tissue. Here, we present a refinement of the ChIP-seq procedures to enable transcription factor mapping on limited amounts of tissue culture cells and illustrate the applicability of this refined technology by mapping the ERa genome-wide chromatin binding landscape in core needle biopsy material from primary breast tumors.