Table 3. Polymorphic variation in UGT associated with irinotecan toxicity (p < 0.05).

UGT allele	Clinical effect
UGT1A1*28	Increased severe neutropenia in Caucasians [32,34-38,46,88] and Japanese populations [41,42] Increased leukopenia in Japanese populations [39-41] Decreased ANC nadir in Caucasians [31,32] Increased severe diarrhea in Caucasians [38,43-46] and Japanese populations [39,40]
UGT1A1*60	G/G genotype was associated with severe hematologic toxicity when compared with T/T at frst cycle in Caucasians [70] but was not confirmed in multivariate analysis
UGT1A1*93	Increased severe neutropenia in Caucasians [32,37,69] Decreased ANC nadir in Caucasians [32]
UGT1A1*6	Increased severe neutropenia in Japanese populations [41,42,48,49,60,64], Koreans [48,49] and Chinese populations [59] Increased leukopenia in Japanese populations [41]
UGT1A7*2	Lack of severe neutropenia or diarrhea in Caucasians [47]
UGT1A7*3	Lack of severe neutropenia or diarrhea in Caucasians [47] Increased severe hematologic toxicity in Caucasians [70] Increased severe diarrhea in Koreans [48,49]
UGT1A7*4	Increased severe neutropenia and/or diarrhea in Caucasians [46]
UGT1A9*1b	Increased severe neutropenia or diarrhea in Caucasians [47] Increased severe neutropenia in Japanese populations [60] Severe hematologic toxicity in Caucasians [70] Decreased severe diarrhea in Koreans [48,49]

ANC: Absolute neutrophil count; UGT: Uridine 5′-diphosphoglucuronosyltransferase.