ESR1 and breast cancer: The latest analysis of the breast cancer genome by the Harvard University research team shows that estrogen processing can directly induce DNA double-strand breaks in the region where the estrogen receptor is located so that cells repair the break through intrachromosomal rearrangement and directly induce the copy number amplification of oncogenes involved in cancer development and development.45,46 Therefore, patients with hormone receptor-positive breast cancer may be more likely to obtain high DNA damage and high HRD scores.