Curcumin, which is extracted from the plant Curcuma longa, has been used in the therapeutic arsenal for clinical oncology. Curcumin has chemopreventive and antitumoral activities against some aggressive and recurrent cancers. The expressions and activities of various proteins, such as inflammatory cytokines and enzymes, transcription factors, and gene-products linked with cell survivals and proliferation, can be modified by curcumin. Moreover, curcumin decreases the toxic effect of mitomycin C. Though curcumin has shown highly cytotoxic to some cancer cell lines, curcumin is insoluble and instable in water. The solubility of curcumin could be enhanced by utilizing the solubilizing properties of rubusoside. In addition, the selective delivery of synthetic analogs or nanotechnology-based formulations of curcumin to tumors may improve the chemopreventive and chemotherapeutic effects. The focus of this short review is to describe how curcumin participates in antitumor processes in breast cancer cells.