Recent advance in understanding of Th17 development revealed that mammalian target of rapamycin (mTOR) induced hypoxia-induced factor (HIF)-1α determined the fate of T cell whether it differentiated into Th17 or Treg [3], suggesting mTOR-HIF-1α as a promising target for RA treatment. The gene discussed is HIF1A; the disease is rheumatoid arthritis.