MKI67 and breast cancer: Considering the scarcity of experimental models which accurately mimic clinical dormant phenotypes, characterised by low or absent expression of proliferation markers (e.g., Ki-67, PCNA), upregulation of dormancy-associated genes (e.g., NR2F1, DEC2, p27), resistance to chemotherapy, and altered metabolic and signalling pathways, the understanding of how dormant BC cells are induced and sustained remains critical for developing clinically-relevant experimental models.