RARA SE presence predicts pAML in vivo sensitivity to tamibarotene. (A) Effect of tamibarotene (6 mg/kg by oral gavage daily) on peripheral blood leukemic burden in p401, a RARA SE+ pAML PDX mice (n = 5 per arm). (B) Effect of tamibarotene treatment on the liver and spleen weights of p401 PDX mice at time of euthanasia. (C) Effect of tamibarotene treatment on survival of p401 PDX mice. (D) CD38⁺ cells percentage in response to tamibarotene treatment in p401 PDX mice. (E) Effect of tamibarotene on the peripheral blood leukemia burden of p198, an RARA SE− pAML PDX (n = 6 per arm). (F) Effect of tamibarotene treatment on the liver and spleen weights of p198 PDX mice at time of euthanasia. (G) Effect of tamibarotene treatment on survival of p198 PDX mice. (H) Body weights of both p401 and p198 mice treated with tamibarotene over time. **.001 < P < .01; ***.0001 < P< .001. n.s., not significant.