In accordance with the results shown in mouse BMMNCs, BC treatment for 2–15 min led to a general significant increase in the MFI of p-FLT3 Tyr591 staining in CD34+ UCB cells (Figure 4A,B), and a similar increasing trend was also observed in the MFI of p-FLT3 Tyr842 and p-cKIT Tyr719 staining, but the MFI value was still very low (Figure S2A–D). Here, FLT3 is linked to breast cancer.