ABCG2 polymorphisms, 34G>A and 421C>A in a Korean population: analysis and a comprehensive comparison with other populations

Background and objective: ABCG2, also known as Breast Cancer Resistance Peptide (BCRP) or mitoxantrone-resistant protein, is the second member of the G-family of ABC transporters. The frequencies of ABCG2 34G>A and 421C>A polymorphisms in a Korean population were assessed using a newly developed multiplex pyrosequencing method, and compared with the corresponding frequencies seen in other ethnic groups. Method: We designed a multiplex pyrosequencing method to simultaneously detect ABCG2 421C>A and 34G>A polymorphisms and analysed the allele frequencies of these polymorphisms in 250 Korean subjects. Results: The results showed 100% concordance between single and multiplex pyrosequencing methods. We also validated the polymorphisms identified by pyrosequencing with a direct sequencing method using randomly selected samples. The allele frequencies of ABCG2 421C>A and 34G>A in the population tested were 0·298 and 0·190 respectively. The allele frequency of the 421C>A polymorphism is comparable to other Asian populations, including Japanese and Chinese. However, both frequencies are different from those of Caucasians and Africans. Conclusions: The multiplex pyrosequencing method used to detect two ABCG2 polymorphisms concurrently is a rapid and reliable genotyping method for the detection of important ABCG2 genetic polymorphisms. The ABCG2 34G>A and 421C>A polymorphisms are frequently found in the Korean population. The frequencies are similar to those seen in other Asian populations including Japanese and Chinese, but very different to those of Caucasian and African-American populations.