After chemotherapy‐induced DNA damage, tumor cells can stimulate cell cycle checkpoints to arrest the cell cycle and start the DNA repair process.[31] It is reported that NCTD can inhibit PP2A to stabilize MDM2 and downregulate p53, thus promoting cell cycle progression to accelerate cell apoptosis.[32] Therefore, we performed the Ser/Thr phosphatase assay to determine the PP2A activity in 4T1 cells after each treatment. This evidence concerns the gene MDM2 and neoplasm.