At the molecular level, ERAS is known to act through the PIK3CA-AKT pathway [5,12,13,14] (involved in cell growth and proliferation, as well as in promoting tumor formation); consequently, we have found in ERAS-expressing mammary glands the activation of this PIK3CA-AKT pathway, as well as the overexpression of cyclin D1, a protein needed for the progression trough the cell cycle. The gene discussed is PIK3CA; the disease is neoplasm.