In summary, these results collectively demonstrated that the heptapeptide KLWVIPQ was capable of suppressing proliferation, accelerating apoptosis, and up- and downregulating P53 and P210bcr/abl expression, respectively, for the IFN-α-sensitive KT-1/A3 CML cells but has no effects on IFN-α-resistant KT-1/A3R CML cells. This evidence concerns the gene TP53 and chronic myelogenous leukemia, BCR-ABL1 positive.