Accordingly, we decided to genotype the breast cancer patients of our study for the CYP2D6 alleles ∗1, ∗2, ∗4, ∗5, ∗6, ∗10, ∗17, and ∗41 as well as the gene duplication to comprehensively cover CYP2D6 alleles representative of the Iran population (Isfahan province). This evidence concerns the gene CYP2D6 and breast carcinoma.