MKI67 and cancer: Minichromosome maintenance (Mcm) proteins 2–7 are present through all phases of the proliferative cell cycle, but are absent in ‘out-of-cycle’ states, suggesting functions as replication licensing factors (Stoeber et al, 2001), and Dudderidge et al (2005) have proposed that the Mcm2-Ki67 labelling index (LI) reflects the presence of non-proliferating dormant ‘cancer stem’ cells, associated with reduced disease-free survival in renal cell carcinoma cases.