Although AD and cancer are associated with age, previous studies [3–5,24–26] have demonstrated an inverse relationship between cancer and AD in several aspects, including estrogen, P53 expression, neurotrophins and growth factors (NGF), epidermal growth factor receptor (EGFR), cAMP, and PI3K/AKT/mTOR pathway, among others. The gene discussed is BDNF; the disease is Alzheimer disease.