However, this p53-mediated response does not seem to be important for suppressing cancer since mice defective for it, but not other p53 responses (p533KR/3KR) [51] and mice deleted for p53 DNA damage targets (p21−/−, Puma−/−, Noxa−/−) [52] do not exhibit early lymphomas and sarcomas as do p53-null mice [53]. This evidence concerns the gene PMAIP1 and lymphoma.