Kaplan-Meier plots show rates of overall survival and event-free survival according to leukemic blast expression of the OCTN1 transporter gene SLC22A4 in a cohort of 134 pediatric patients with AML (A, B), an independent cohort of 54 pediatric patients with AML (C), and a cohort of 172 adult patients with AML (D, E), all receiving cytarabine-based chemotherapy. Gene expression ranks represent low expressors (bottom 1/3; shown in RED), intermediate expressors (middle 1/3; shown in BLACK) and top expressors (top 1/3; shown in BLUE).