BC subtypes changed in 4/114 (3.5%) of HER2+ve, 10/114 (8.8%) of hormone positive (ER or PR) with HER2 overexpression (HER2+ve/HR+ve), 3/114 (2.6%) in hormone positive with HER2 negative (HR+ve), and 3/114 (2.6%) triple-negative BCs. This evidence concerns the gene ESR1 and breast cancer.