Thus, the high degree of specificity of AM9D for targeting MMP-9, its in vivo stability, and the lack of any observed in vivo toxicity (Hallett M, Dalal P, Sweatman T, Pourmotabbed T: Naked Anti-Matrix Metalloproteinase-9 DNAzyme Administered Systemically Distributes to All Organs of Healthy and MMTV-PyMT Transgenic Mice and Is Safe; manuscript in review) should enhance the clinical response of solid tumors, including breast tumors, to AM9D treatment, while evading the serious side effects experienced with systemic therapy based on broad-spectrum MMP inhibitors. This evidence concerns the gene MMP9 and breast neoplasm.