More specifically, Sher et al. [50] constructed the hEndoyCD fusion protein, composed of the antiangiogenic endostatin and the Escherichia coli cytosine deaminase (CD) domain which converts 5-fluorocytosine (5-FC) to 5-FU, and delivered it to ovarian cancer cells via a plasmid vector (SV-hEndoyCD). Here, CTLA4 is linked to ovarian cancer.