As examples, a high rate of loss of response to imatinib in CML was associated with the SLC22A1/OCT1 variant rs683369 (C490G) [36] and increased time to progression of gastrointestinal stromal tumors (GISTs) on imatinib was associated with the SLC22A4/OCTN1 variant rs1050152 (C1507T) [37]. The gene discussed is SLC22A4; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.