Abstract: The present invention relates to a novel use of erythroid differentiation regulator 1 (Erdr1) as an agent for treating cancer. More particularly, it relates to an use of Erdr1 or an expression vector including a polynucleotide encoding the same for preventing and inhibiting cancer metastasis, an use of Erdr1 or an expression vector including a polynucleotide encoding the same for preventing and treating cancer, an use of an antibody specific for Erdr1 for diagnosing cancer, or a method for screening agents for regulating cancer metastasis or cancer cells migration. The Erdr1 is negatively regulated by IL-18 expression and it suppresses migration, invasion and metastasis of cancer or tumor cell by expression of HSP90 and generation of ROI. And an Erdr1 recombinant protein promotes NK-cell killing activity against cancer cell.