Since α6β4 regulates ErbB-3 level and the depletion of either β4 or ErbB-3 proteins resulted in a strong inhibition of Akt activation, the data confirm the essential role of ErbB-3 in the activation of Akt by α6β4 integrin in mammary tumor cells (Figure 2B). The gene discussed is ERBB3; the disease is breast cancer.