KIT and plasma cell myeloma: Further analysis of the cell cycle and apoptosis showed that most HSPCs (LSK: Lin−c-Kit+Sca-1+, and LSK−: Lin−c-Kit+Sca-1-) were arrested in G0 phase of the cell cycle in the myeloma model mice compared with tumour-free control mice (G0 phase, LSK−: 41.88% ± 6.97% vs. 18.48% ± 1.56%, p = 0.0083; LSK: 55.60% ± 2.61% vs. 18.85% ± 1.01%, p < 0.0001; Fig. 3C).