The aims of this study were to determine: 1) whether V. odorata extract would effectively decrease the size of tumors in 4T1 breast cancer mouse model, 2) whether there would be changes in metastatic rate, expression of Ki-67 (cell proliferation) and CD31 (angiogenesis) determined by histopathological studies in mice treated with V. odorata, 3) the changes in antioxidant enzyme activity (SOD and CAT), liver enzymes (LDH, ALP, GGT) and tumor markers (CA15-3 and CEA) levels in response to V. odorata. This evidence concerns the gene MKI67 and neoplasm.