a method induces cancer , such as ovarian cancer , in primates for testing of therapeutic treatments and preclinical research and development . a nanoparticle delivers plasmid dna encoding oncogenes and sirnas for tumor suppressor genes . for example , a biocompatible polymer , chitosan , is complexed with three plasmids including one that carries the cdna encoding ras oncogene and two plasmids encoding sirnas for two tumor supressor genes p53 and rb . laproscopic delivery of these nanoparticles to the ovaries of non - human primates causes ovarian carcinoma , which is detected one month after delivery of the nanoparticles .