SLC22A1 and chronic myelogenous leukemia, BCR-ABL1 positive: Although IM is a substrate of hOCT1 [20], it has been shown in previous single marker studies that 1222A>G (rs628031) does not alter the function of the hOCT1 protein [46] and does not affect response to IM therapy in CML patients [12], [24], [26], [27].