eBC: early breast cancer; ET: endocrine therapy; FSH: follicle-stimulating hormone; HER2-: human epidermal growth factor receptor 2-negative; HR+: hormone receptor-positive; LHRHa: luteinizing hormone releasing hormone analog; OFS: ovarian function suppression; RANK: receptor activator of nuclear factor-kappaB. Here, ERBB2 is linked to breast cancer.