To screen for proteases mediating A70 formation in melanoma cells independently of Furin, a B16-F1 FurKO clone that stably expresses INHBA (FurKO#1-βA) was transfected with siRNA pools against 542 known proteases, followed by co-culture with HepG2.α1-PDX CAGA-Luc reporter cells (Fig. 1D). Here, FURIN is linked to melanoma.