Deletion of Il6 in MSCs inhibits the progression of AML. (A) Kaplan-Meier survival curves of Il6^fl/fl and Il6_Prrx1^–/– AML mice. (B) The proportion of AML cells in the BM and PB of Il6^fl/fl and Il6_Prrx1^–/– AML mice. (C) Spleen size and weight in Il6^fl/fl and Il6_Prrx1^–/– AML mice. (D) Liver size and weight in Il6^fl/fl and Il6_Prrx1^–/– AML mice. (E) Hematoxylin and eosin (H&E) staining was used to assess the infiltration of AML cells in BM, splenic, and hepatic tissues (scale bar, 100 μm). (F) FCM was used to quantify the infiltration ratio of AML cells in the splenic and hepatic tissues. (G) FCM analysis of YFP⁺MLL:: AF9 AML cell homing to PB, BM, and spleen at 18 hours after transplantation into Il6^fl/fl and Il6_Prrx1^–/– recipient mice. (H) Ki67 staining of AML cell isolated from Il6^fl/fl and Il6_Prrx1^–/– AML mice to assess proliferative activity (n = 5 mice per group). Data are presented as mean ± SD. Log-rank (Mantel-Cox) test was used for survival study comparisons (panel A). Differences analyzed using ordinary 1-way ANOVA with Tukey multiple comparisons test (panels C-D), 2-way ANOVA with Sidak multiple comparisons test (panel G), or 2-tailed unpaired t test (panels B,F,H). ∗P < .05; ∗∗P < .01; ∗∗∗∗P < .0001. Nor, normal healthy mice; ns, not significant.