That ability makes RNAi a potential fix for many diseases, including cancer, that arise when abnormal cells produce excessive amounts of everyday proteins. In theory, manipulating RNAi to kill proteins is simple. ALN-
VSP,
for example, consists of synthetic double-stranded RNA designed to match tumor mRNA that codes for two proteins: VEGF, which cancers overproduce to help grow new blood vessels, and KSP, which sets off rapid cell division.