Lifestyle, including alcohol intake and smoking, has a major impact on promoting breast cancer malignancy through the overproduction of estrogens, alterations in estrogen receptors, oxidative stress, DNA damage, genotoxicity, epithelial–mesenchymal transition promotion, and over-activation of epidermal growth factor receptor (EGFR)/ErbB2 signaling [125,126]. The gene discussed is ERBB2; the disease is breast carcinoma.