MAPK8 and cancer: Although a previous study showed that in response to neurotrophin signaling, NGFR might mediate p53-dependent neuron cell death by activating the JNK pathway (Aloyz et al., 1998), our studies as presented here unveil a novel nuclear function of this membrane receptor, i.e., to promote cancer cell proliferation and survival by directly inhibiting p53 transcriptional activity and indirectly destabilizing p53 protein via MDM2.