The pathogenesis of breast cancer is associated with pathologic activation of several key signaling pathways, especially the phosphoinositide 3-kinase (PI3K) pathway (Mayer & Arteaga, 2016; Paplomata & O’Regan, 2014; Yang, Polley & Lipkowitz, 2016). The gene discussed is PIK3CD; the disease is breast carcinoma.