SLCO1B1 and Decreased total neutrophil count: Innocenti et al (2009) showed that irinotecan-induced neutropenia can be explained in part by the UGT1A1*93, ABCC1 IVS11 –48C>T and SLCO1B1*1b 388A>C genetic polymorphisms, but in their study, irinotecan was administered at considerably higher doses (300–350 mg m–2); therefore, it is not surprising that we could not reproduce these associations.