TKT and chronic myelogenous leukemia, BCR-ABL1 positive: Primary leukemic cells of some CML patients lack CAR and are therefore resistant to Ad5 transduction, gene transfer efficiency of Ad5 can differ greatly among individual CML patient cells [35] (gene transfer rates of RGD-Ad5 can be 30 ~ 80%), which means different apoptosis effect of Ad-AS-TK/GCV system for different CML patient cells.