Rebiopsy of the right breast tumor revealed the following results: ER Allred score 2 (PS 1 [< 1%], IS 1), PgR Allred score 2 (PS 1, IS 1), HER2 IHC 2+, HER2 fluorescence in situ hybridization negative (HER2/HER2/CEP(centromere)17 = 0.9), and programmed death ligand 1 (SP142) expression on tumor-infiltrating immune cells of 1%-4%. Here, ESR1 is linked to neoplasm.