TP53 and neoplasm: Indeed, we find that loss of GATA4 in human tumors occurs largely in the presence of TP53 mutation or deletion, suggesting a conditional tumor-suppressive role of the GATA4-SASP pathway only in the absence of TP53. Which signals and at what strength they are needed to activate the TP53 versus GATA4 branches in tumors is not known nor is the composition of the SASP pathway in these contexts.