We observed that the subcutaneous tumor weight in mice receiving MM189 PB-Klf4 cells (0.3886±0.02272 g, n = 7) was reduced when compared with the tumor weight in mice injected with cells containing the vector control (0.5871±0.08138 g, n = 7) (Figure 2A). This evidence concerns the gene KLF4 and neoplasm.