Although additional in vivo studies are warranted to validate the clinical efficacy of DK4023 in a metastasis animal model, we propose that DK4023 can serve as a promising agent to target the TNFα-ERK1/2 MAPK-EGR-1-MMP9 signaling pathway for the development of a chemopreventive or chemotherapeutic adjuvant, which can be used in combination with conventional chemotherapy, radiotherapy, or immunotherapy against metastatic cancers, particularly breast cancer. This evidence concerns the gene MMP9 and metastatic malignant neoplasm.