Chonlaphat SukasemChalirmporn AtasilpPichai ChansriwongMontri ChamnanphonApichaya PuangpetchEkapob SirachainanMahidol UniversityFaculty of Medicine, Ramathibodi Hospital, Mahidol University2018-12-112019-03-142018-12-112019-03-142016-01-01Journal of Clinical Laboratory Analysis. Vol.30, No.1 (2016), 84-8910982825088780132-s2.0-84954076213https://repository.li.mahidol.ac.th/handle/20.500.14594/43133© 2016 Wiley Periodicals, Inc. Background: UGT1A1 is a polymorphic enzyme that has been associated with irinotecan drug metabolisms. We developed a pyrosequencing method to detect allele frequency and genotype of UGT1A1 polymorphisms (UGT1A1*28 and UGT1A1*6) in Thai colorectal cancer patients. Method: A pyrosequencing method was designed to determine UGT1A1 genetic polymorphisms including UGT1A1*28 (A[TA]7TAA) and UGT1A1*6 (211G>A) in 91 Thai colorectal cancers. Result: Genotyping by the pyrosequencing technique was 100% concordant with capillary electrophoresis sequencing. The allele frequencies for UGT1A1 genetic polymorphisms were *1/*1 (54.95%), *1/*6 (13.19%), *1/*28 (25.27%), *28/*6 (4.40%), and *28/*28 (2.20%). No homozygous mutation UGT1A1*6 was found in our population. Conclusions: We developed a rapid, reliable, more cost-effective, and simple assay to detect UGT1A1 genetic polymorphisms in routine practice before initiating irinotecan therapy. The UGT1A1*28 and UGT1A1*6 alleles were found to be similar in the Asian populations.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyHealth ProfessionsArticleSCOPUS10.1002/jcla.21820