Patients with homozygosity for UGT1A1*28 (*28/*28) or UGT1A1*6 (*6/*6) and heterozygosity for both UGT1A1*28 and *6 (*28/*6), which are associated with severe CPT-11-related neutropenia in Japanese patients, were coincidentally not enrolled in this study. The gene discussed is UGT1A1; the disease is neutropenia.