Tumours were classified into four molecular subtypes: HR + /HER2- (estrogen receptor positive and/or progesterone receptor positive, HER2 negative), HR + /HER2 + (estrogen receptor positive and/or progesterone receptor positive, HER2 positive), HR-/HER2 + (estrogen receptor negative and progesterone receptor negative, HER2 positive), and triple-negative (HR-/HER2-: estrogen receptor negative and/ progesterone receptor negative, HER2 negative). The gene discussed is ESR1; the disease is neoplasm.