MCTs are tissue-specifically expressed: MCT1 is ubiquitously expressed, but highly expressed in myocytes [74], adipocytes [41], and MM cells [40]; MCT2, specifically in the brain and the kidney but not in MM; MCT4, in skeletal muscle, adipocytes, the heart, the lung, and the brain [41,43,74,75], also in malignant tumor cells [76] including MM cells [40]. Here, SLC16A7 is linked to Miyoshi myopathy.