In cancer, ID proteins are induced by oncoproteins (e.g., MYC, RAS, SRC, Notch, EWS-FLI1, and receptor tyrosine kinases) and growth factor-directed signals (e.g., epidermal growth factor [EGF], basic fibroblast growth factor [bFGF], transforming growth factor-β, and bone morphogenetic proteins)30. The gene discussed is NTRK1; the disease is cancer.