UGT1A1 genotyping analysis
UGT1A1 genotyping was performed using the Invader assay, a DNA analysis method that consists of a two-step isothermal reaction using a structure-specific flap endonuclease, as previously reported12. Based on the results of testing forUGT1A1*6 and *28 genetic polymorphisms, patients were divided into three groups: wild-type group (−/− ); heterozygous group (*28/− and *6/− ); and homozygous group (*28/*28 , *6/*6 , and *28/*6 ). Patients with double heterozygosity (*28/*6 ) were classified into the homozygous group13.