In one such study, the anthrax toxin was fused with zymogen activating prodrug and to make it specific for ovarian cancer cells, the PA was modified such that now it could be activated my membrane-anchored serine proteases (MASPs) instead of the classical activation by furin cleavage at RKKR because the MASPs are overexpressed in the ovarian cancer. Here, FURIN is linked to ovarian cancer.