FLT3 and plasma cell myeloma: Our data showed that the frequency of LT-HSCs (Lin−, c-kit+, Sca-1+, CD34−, CD135-) in the bone marrow of the myeloma mouse model was notably increased compared to that in control mice (21.13% ± 0.85% vs. 7.55% ± 1.46%, p < 0.0001; Fig. 3A,B).