The study aims to investigate the possible effect of genetic polymorphisms in certain metabolizing enzymes [CYP3A5*3 (rs776746), CYP2C8*3 (rs11572080 and rs10509681)] and membrane transporters [ABCB1 2677G>T/A (rs2032582) and SLC22A1 1222A > G (rs628031)] by PCR on the plasma level (by HPLC-UV) and molecular response (MMR) of imatinib in patients with CML.