Targets in downstream or resistant pathways of particular interest in HER2-positive breast cancer include mTOR, PI3K, IGF-1R, Akt, HSP90, and VEGF that allow cell development, survival, and differentiation (Agus et al., 2005; Arteaga et al., 2012; Franklin et al., 2004; Nahta et al., 2006). The gene discussed is ERBB2; the disease is breast cancer.