LM10, a TDO2 inhibitor with improved solubility and bioavailability,174 was used to show that TDO2 inhibits anti-tumour immune responses and promotes tumour growth in a murine cancer model.15 Other single TDO2 inhibitors are also under development, several of these such as fused imidazo-indoles-based inhibitors developed by RedX Pharma (Patent WO 2016/051181, Patent WO 2016/059412) and indazole-based TDO2 inhibitors developed by IOmet Pharma (Patent WO 2016/071283, Patent WO 2015/150097) are currently in various stages of experimental or preclinical studies. This evidence concerns the gene TDO2 and cancer.