SLCO1B1 and acute lymphoblastic leukemia: The only GWAS on MTX-related phenotypes to date identified an association between variant rs11045879 in SLCO1B1 and MTX clearance in patients with ALL, which was replicated by others (Trevino et al., 2009; Lopez-Lopez et al., 2011; Radtke et al., 2013; Ramsey et al., 2013; Csordas et al., 2014; Goricar et al., 2014; Zhang et al., 2014; Liu et al., 2017).