At least 9 MCT-related proteins (MCT1-9) have been identified in mammals that are expressed in a tissue specific manner.MCT4/MOT4/SLC16A3 (mouse 470-aa, rat 471-aa, human 465-aa; chromosome 17q25) is most closely related to MCT3, is prominently expressed in skeletal muscle and other cells with a high glycolytic rate such as tumor cells and white blood cells, suggesting an important role in lactic