It was also revealed in this review article that the reduced expression level of OCT1 and OCT2 in hepatic and renal cancer, respectively, has been extensively associated with the pharmacological ramifications, namely drug resistance, but rather neglected with respect to the biological meaning of such a repression, yet this is an interesting aspect to elucidate, especially in light of the emerging role of OCTs in cell energetics [141,142,143]. Here, SLC22A2 is linked to renal carcinoma.