The present invention relates to a novel use of Msx1 protein or a nucleotide encoding the same for inducing apoptosis. The Msx1 of the present invention induces apoptosis through direct interaction with p53 via a homeodomain and such interaction leads to increased stability, and/or nuclear localization of p53 in cells. The Msx1 or homeodomain thereof can be effectively used for the treatment of tumors, in which wild-type p53 protein has lost its function by some mechanism that inactivates p53 proteins.
