Similar data have been reported in other studieswhere co-transfection of two tumor suppressor genes led to a notable increase in tumor cell death For example, co-transfection of p53 and ING4 in breast cancer,20 PTEN and ING4 in hepatocellular carcinoma19 and p53 and p33 in gliomas.28 Notably, PTEN induced apoptosis more effectively than p53, as demonstrated by MTT and flow cytometry assays, where PTEN led to 70% higher cell death and 30% more apoptosis compared to p53. This evidence concerns the gene PTEN and breast cancer.