The recent discovery of a cell surface receptor for lactate in mammalian cells represents a new era in terms of understanding the exact connection of the Warburg effect to cancer; in fact, lactate transmits pro-tumor signals through its G-protein-coupled receptor 81 (GPR81), highly expressed in breast, pancreatic and cervical carcinomas, whilst negligibly expressed in the benign epithelium of these tissues [8]. The gene discussed is HCAR1; the disease is cancer.