Histopathological examination confirmed the presence of two biologically distinct carcinomas: 1) invasive ductal carcinoma, grade 1, ER+/PR+ (>90%), HER2-negative, measuring 0.9 cm, Ki-67 index 10%; and 2) invasive ductal carcinoma, grade 3, triple-negative phenotype (ER-/PR-/HER2-), measuring 1.7 cm, Ki-67 index 30%. The gene discussed is MKI67; the disease is invasive ductal breast carcinoma.