PARP1 and neoplasm: Given the importance of p21 and Bax in determining cellular fate, cell cycle arrest for tumor cell survival or onset of apoptosis for tumor death, demonstration of biochemical consequences on KLF4 PARylation by PARP1 in dictating KLF4‐mediated transcriptional regulation of p21 and Bax uncovers a new aspect of the molecular basis of DNA damage response (Fig 9).