A comparison of Casp3 KO cells with wild-type cells demonstrated that apoptotic caspase-3 induced tumor repopulation in NSCLC by 1) inducing DDR via activation of the ATM/p53 signaling pathway and by 2) activating the Cox-2/PGE2 axis via p53. The gene discussed is PTGS2; the disease is non-small cell lung carcinoma.