The ideal antigen should be overexpressed on cancer cells, while the expression levels on normal, healthy cells should be extremely low.[95] Examples of biomarkers that are targeted in TAT studies are epidermal growth factor receptor variant III, human epidermal growth factor receptor 2 (HER2), folate receptor alpha, tenascin-C, CD20, CD33, and prostate-specific membrane antigen (Table 2). The gene discussed is ERBB2; the disease is cancer.