BCL2 and cancer: They identified BCL2 and successfully recovered the tumor sensitivity toward chemotherapy.124 Interestingly, Carlet et al. used Cre-ERT2 inducible RNAi to mimic anti-cancer therapy and silence genes in PDX models, which combined the properties of the Cre-loxP system and RNAi techniques.125 A DNA barcode sequence is a type of unique sequence which can track the exact cells or components that carry it.126 Researchers have loaded DNA barcodes and drugs in nanoparticles and injected them into tumor-bearing mice, which helped identify the exact drugs that most efficiently kill cancer cells.127