Differentiation therapy with cd137 ligand agonists

12-33. (canceled)

A method for inducing differentiation in cancer cells, comprising administering an agonist of CD137 ligand (CD137L) to said cancer cells, wherein the agonist of CD137L is selected from the group consisting of a fragment of CD137 protein, a recombinant CD137 protein, a CD137 fusion protein, an anti-CD137L antibody or a fragment thereof, a peptide, a small molecule, an aptamer, and an antibody mimetic.

A method for delivering a therapeutic or diagnostic agent to a cell in need thereof, comprising coupling an agonist of CD137 ligand (CD137L) to an agent selected from the group consisting of cytotoxic drugs, radiotherapeutics, chemotherapeutics, enzyme, and a carrier molecule, wherein the agonist of CD137L is selected from the group consisting of a fragment of CD137 protein, a recombinant CD137 protein, a CD137 fusion protein, an anti-CD137L antibody or a fragment thereof, a peptide, a small molecule, an aptamer, and an antibody mimetic.