SLC16A3 and nonpapillary renal cell carcinoma: Lastly, solute carrier family 16, member 3 (SLC16A3 or MCT4, Gene ID: 9123; mRNA increased 87-fold in TRACK mice and nearly 7-fold in ccRCC) is a monocarboxylate transporter that is upregulated in many tumors because it is required for lactate secretion out of the cell, pH homeostasis, and maintenance of the Warburg effect [38].