Breast cancer is considered as the most familiar cancer in females which represented 38.8 % in Egypt and 29% in the world. It is the second common cause of cancer-related death in women. Treatment of breast cancer with chemotherapeutic agent as Doxorubicin may lead to many side effects, mainly cardiac and renal fibrosis. The present study aimed to investigate the underlying molecular mechanisms for the potential anti-fibrotic effect of pirfenidone (500mg/kg, P.O. once daily) and Vitamin D (0.5µg/kg I.P. once daily) against doxorubicin (15 mg/kg I.P.) induced cardio- and renal- fibrosis. Moreover, the anti-cancer potential of pirfenidone (PFD) and Vitamin D either alone or in combination with doxorubicin will be assessed in a xenograft experimental model of breast cancer. Then, tissue and blood samples will be collected after two weeks post-treatment to assess the toxicity of Doxorubicin and to determine how pirfenidone and vitamin D protect against the toxicity of Doxorubicin .