ESR1 and breast neoplasm: The breast tumor measures 1.2 × 0.9 × 1.0 cm3 (T1), is estrogen receptor positive with an H score of 280, is progesterone receptor negative with an H score of 0, and is HER2 equivocal 2+ by immunohistochemistry with a fluorescence in situ hybridization ratio of 1.9 with a copy number of 5.