As cancer cells, trophoblast derived cells express several proto-oncogenes; for example, CTB and STB exclusively express proto-oncogenes that encode Growth Factor Receptor c-erbB1 (Human Epidermal Growth Factor Receptor 1 (HER1), Epidermal Growth Factor Receptor 1 (ERBB1 or EGF-receptor)) (63). The gene discussed is EGFR; the disease is cancer.