Using dual-luciferase reporter assays in U-CH2 and UM-Chor1 chordoma cells expressing endogenous TBXT, 6 of 23 candidate DARPins (A2, B1, B6, C3, D3, and D4) blocked TBXT binding to the response elements, as evidenced by a reduction in the luciferase signal by more than 50% relative to E3_5 (Fig. 1D). The gene discussed is TBXT; the disease is chordoma.