Distribution of and gene polymorphisms in Han and Uygur populations with breast cancer in Xinjiang, China.

The aim of this study was to investigate the frequency distribution of the cytochrome P450 () enzymes, and , and the form of tamoxifen metabolisation in premenopausal patients with breast cancer in the Han and Uygur ethnic groups of Xinjiang to guide rational clinical drug use. A total of 125 Han patients and 121 Uygur patients with premenopausal hormone-receptor-positive breast cancer treated at the Xinjiang Uygur Autonomous Region Cancer Hospital between 1 June 2011 and 1 December 2013 were selected. The common mutation sites in were analysed using TaqMan® minor groove binder technology. Genetic testing was performed to determine other metabolic types of tamoxifen, and the genotypes and metabolic types were compared using a Chi-squared test. Between the Han and Uygur groups, there were significant differences in the frequencies of the (*10/*10) and (*1/*1) genotypes, with values of 0.002 and 0.015, respectively. Genotypes of (*1/*1), (*1/*5), (*5/*5), (*5/*10) and (*3/*3) were expressed in the two patient groups, and the difference was not statistically significant ( > 0.05). In the Han patients, the proportions of extensive, intermediate and poor metabolisers of tamoxifen were 72, 24 and 4%, respectively, whereas those in the Uygur patients were 76.9, 17.4 and 5.7%, respectively, with no significant difference ( > 0.05). In conclusion, There were partial differences in the and gene polymorphisms of between the Han and Uygur patients with premenopausal breast cancer, but there was no significant difference between the and phenotypes. Further research is needed to determine the relationship between the enzyme genetic differences of and the pharmacokinetics and efficacy of tamoxifen. Although there were some differences in genotypes, these did not result in differences in the predicted tamoxifen metabolisation phenotype between the Han and Uygur patients with breast cancer. Therefore, the doses should be adjusted according to the individual genotype data.