In this study, although intense staining of phospho-Akt-Th308 in both the cytoplasm and nucleus was immunohistochemically observed in mammary carcinoma tissues of the control group, the intensity and number of cells expressing phospho-Akt-Th308 tended to be lower in the 20 mg/kg/day α-mangostin group. This evidence concerns the gene AKT1 and breast carcinoma.