We explored the impact of genetic variability (single nucleotide variants—SNVs) of drug transporter genes (ABCB1, ABCG2, SLC22A1, and SLC22A5) on CML susceptibility, drug response, and BCR-ABL1 mutation status. This evidence concerns the gene ABCG2 and chronic myelogenous leukemia, BCR-ABL1 positive.