SLC22A4 and cancer: EM–T–MEL, EM–I–MEL, or EM–MORPIP–MEL can be transported to cancer cells by other membrane receptors that are overexpressed in leukemia cancer cells: MCT-1, -2, and -4, for lactate transport; OAT-1, for small, hydrophilic organic anion transport; OCTN-1, FLIPT-1, and OCT-6, for organic cation transport; and OATP1B1 and OATP1B3, for large, hydrophobic anion transport [29].