For example, Ngai et al. showed that Doxil, a liposomal doxorubicin formulation prepared with PEG-modified lipids, increased the spatial distribution of cell death as measured by caspase 3 activation in 4T1 breast tumors compared to what can be achieved with free doxorubicin [65]. The gene discussed is CASP3; the disease is breast neoplasm.