In addition, the expression rate of PR gradually decreases in association with a variety of changes that include increased HER-2 positivity, elevated Ki67 index, the emergence of P53 mutations, larger tumour diameters, lymph node metastasis, higher histological grades, the occurrence of triple-negative BC in pathological molecular subtypes, and an advancement in clinical staging. The gene discussed is MKI67; the disease is neoplasm.