TRC105, in combination with mild myeloablation, suppresses the in vivo progression of ALL. (A-C) Effect of TRC105+CPA treatment on ALL progression. (A) Graph shows average percentage of hCD45 in PB. Error bars indicate SEM for each cohort (n = 4-6 each). Red arrow indicates beginning of treatment. ****P < .0001 by ANOVA. (B-C) Representative FACS plots show levels of hCD45 in the BM 11 weeks postinjection of ALL blasts (B), and graph shows average percentage of hCD45, with error bars indicating SEM (C). Leukemia progression was inhibited in the CPA-injected cohort, and this inhibition was significantly potentiated in the presence of combined therapy TRC105+CPA. **P < .01 and ****P < .0001 by ANOVA. (D) Levels of sENG 11 weeks after injection of ALL blast. Bars represent average concentration of sENG and error bars indicate SEM. Measurements were performed using standard quantitative ELISA. ****P < .0001 compared with untreated, ǂǂǂP < .0001 and ǂǂǂǂP < .0001, compared with TRC105 alone, by ANOVA.