Indeed, p53- or p21-deficient cells, but not wild-type p53 fibroblasts, became tumor-like after their uptake of c-myc and H-rasV12 oncogenes, indicating that the Chk2/p53/p21 signaling pathway protects cells against the propagation of potentially harmful DNA [19], [20], [30]. This evidence concerns the gene TP53 and neoplasm.