In order to obtain information regarding the association of DR4 and DR5 expression with PDA cell sensitivity to soluble (s)TRAIL treatment, the authors compared the IC50 for every cell line from the sTRAIL killing curve, revealing a strong direct correlation among DR4 cell surface expression and TRAIL sensitivity, compared with the association observed among DR5 expression and TRAIL sensitivity [55]. The gene discussed is TNFSF10; the disease is Patent ductus arteriosus.