The initiator caspase Dronc and the effector caspase Drice are required for most of the developmental and stress-induced apoptosis in Drosophila, whereas the role of the minor effector caspase, Dcp-1, is largely dispensable. After irradiation-induced apoptosis, both Drice and Dcp-1 become activated in wing imaginal discs (WDs). Here we show that following ionizing irradiation, WD cells compromised for caspase activity change their morphology, form protrusions, loose E-cadherin expression, delaminate and migrate away from their original compartment in an invasive manner. We termed this process irradiation-induced cell migration (ICM), and it is reminiscent of the epithelial-to-mesenchymal transition (EMT). Interestingly, we revealed both autonomous and non-autonomous factors required for ICM induction. We performed a candidate RNAi screen for signaling pathways involved in ICM induction. We then isolated the migrating cells and subjected them to RNA-seq analysis. Here I will describe our recent findings about the pathways and mechanisms underlying this unexpected phenomenon.