A good example of the sort of cellular hacking going on in the laboratory and early trials these days via EurekAlert!: researchers "have developed a nanoparticle - about one thousandth smaller than a printed period - that can travel through the blood stream. 'Decorated' with a tumor-targeting antibody, the nanoparticle is able to locate primary and hidden metastatic tumor cells and deliver its payload: a fully functioning copy of the P53 tumor suppressor gene. ... Normal cells have two copies of the functioning P53 gene. The protein produced by the P53 gene is activated to either coordinate the repair process in cells or induce cell suicide. ... In earlier work using animal models, [researchers] delivered functional p53 genes to tumor cells and tumor metastases in 16 different types of cancer, including prostate, pancreatic, melanoma, breast cancer and head and neck cancer. The presence of the replacement genes dramatically improved the efficacy of conventional cancer therapy. ... When the job of reinstating a normal P53 suppressor gene is done, the nanoparticle - essentially a little fat droplet wrapped around the gene - simply melts away, unlike non-biodegradable delivery systems. ... Clinical trials are now underway ... The trial already has enrolled six patients with various cancers and anticipates a total of 14."