Provide the novel cancer therapeutic agent for being used as the novel selection for the treatment of cancer. Especially provide: a peptide comprising for the PHB2 polypeptides in an ERAP1 polypeptides a binding site and can inhibit to bundle between ERAP1 polypeptides and PHB2 polypeptides A pharmaceutical composition comprising peptide For handling and/or preventing a kind of method for screening for a drug candidate of cancer, wherein the inhibition of the binding between an ERAP1 polypeptides and a PP1 alpha polypeptides, a PKA polypeptides or a PKB polypeptides are used as a measurement.
