【Objective】 To observe UGT1A1*28 genetic polymorphism and the association with the incidence and severity of adverse reaction of irinotecan chemotherapy in Chinese cancer patients with advanced gastrointestinal carcinoma. 【Methods】 UGT1A1*28 genetic polymorphism analysis was performed in 317 patients with cancer from March 2010 to March 2011 in our hospital by amplifying gene fragments using PCR and direct sequencing. Forty-five cases with advanced gastrointestinal cancer treated with irinotecan were observed and recorded the adverse reaction during chemotherapy. The differences of the incidence of grade 3 and 4 adverse reaction were compared in the patients with different genotypes. 【Results】 Of 317 patients of malignant tumor

250 cases (78.9%) were identified with (TA) 6/ (TA) 6 genotype

59 cases (18.6%) were genotyped as heterozygote (TA) 6/ (TA) 7

and 8 cases (2.5%) were found as (TA) 7/ (TA) 7 genotype. In 44 cases with advanced gastrointestinal cancer treated with irinotecan

8.6%

12.5%

and 100% had grade 3 and 4 neutropenia and 14.3%

12.5%

and 100% had grade 3 and 4 diarrhea

respectively. 【Conclusion】The polymorphism of UGT1A1-28 in Chinese patients was low. Patients with (TA) 7/ (TA) 7 genotype treated with irinotecan chemotherapy had increased risk of grade 3 and 4 neutropenia and diarrhea than cases with (TA) 6/ (TA) 7 or (TA) 6/ (TA) 6 genotype. Wild type (TA) 6/ (TA) 6 could be passed screening and how to select the right patients with the appropriate dose of irinotecan in order to improve the efficacy were worthy of further study.