In standard pathology practice, ER and PR IHC are scored at the whole tissue level, and the percentage of immunoreactive tumor nuclei is reported using a semiquantitative scoring system which categorizes samples as positive (≥10% of nuclei immunoreactive), low positive (≥1% to <10% of nuclei immunoreactive) or negative (<1% nuclei immunoreactive). Here, ESR1 is linked to neoplasm.