To determine the extent to which HER family members might potentiate the cellular response to doxorubicin-induced activation of Akt in breast cancer cells, we assessed the effect of treatment with doxorubicin (0.5 to 1 μM) on p-Akt levels in MCF7 cells transfected with a HER2 expression construct (MCF7HER2 cells). Here, ERBB2 is linked to breast cancer.