SLC22A5 and cancer: When primary cancer cells were grouped according to the expression level of OCTN2 as per western blotting and/or immunostaining (Figure 1A; Figure 1B), the Na+-dependent transport of L-carnitine was significantly higher in cells derived from tumor tissues with higher expression of OCTN2 in comparison with that in those isolated from tumors with low expression of OCTN2 (Figure 1E).