Children who underwent HD-MTX for ALL who carry SLCO1B1 polymorphism rs11045879 (c.1865+4846T>C) and rs4149056 were shown to have lower MTX elimination in a genome-wide-association-study (GWAS), whose cohort mostly consisted of Caucasians and a limited number of Asians [20, 22]. Here, SLCO1B1 is linked to acute lymphoblastic leukemia.