In addition, the expression of BMP2 in serum was analyzed by ELISA, which showed that the level of BMP2 in the B-ALL group was significantly higher than that in the control group (p < 0.001, Figure 2G), and the proportion of Treg was significantly positively correlated with the expression of BMP2 (p < 0.05, Figure 2H). This evidence concerns the gene BMP2 and acute lymphoblastic leukemia.