Aurora A kinase is overexpressed in many cancers but the status of this protein in the breast cancer often varies. We investigate the expression and localization of Aurora A protein in relation with tumor emergence and progression in breast cancer. Aurora A kinase status was evaluated in 107 patients using immunohistochemistry. The experimental findings showed that high expression of the Aurora A protein was correlated with elevated nuclear grade, low expression of progesterone receptor and positive nodal status. The experimental results showed also that the localization of this kinase shifts from cytoplasm in non malignant adjacent tissue to both cytoplasmic and nuclear compartments in tumoral tissue, suggesting an oncogenic role of the nuclear accumulation. We have, furthermore, detected the overexpression of this protein in non malignant adjacent tissue. The expression of the Aurora A kinase in non malignant tissue may represent an earlier diagnosis tool for breast cancer.