NR4A1 and lung cancer: On the other hand, ectopic expression of NR4A1 promotes cell cycle progression in lung cancer cells, showing a requirement for its DNA-binding domain and transactivation [25], while it also mediates the mitogenic effects of vascular endothelial growth factor A, and NR4A1 null mice injected with melanoma cells show reduced tumour formation and angiogenesis [37].