Unlike many developmental processes, wing imaginal disc development in Drosophila does not normally involve apoptosis. Irradiation of the disc, however, induces apoptosis in ∼60% of the cells, but, surprisingly,the resultant adult fly has normal wings. On p. 5591,Pérez-Garijo and colleagues report that the expression of Wg and Dpp– two important signalling molecules in fly development – may contribute to the mechanism that normally compensates for cell loss after irradiation. They produced wing aberrations by inducing apoptosis in the imaginal disc and then inhibiting cell death with a caspase inhibitor. These perturbations caused excess proliferation in and modifications to the wing disc's normal compartment boundaries, and the permanent misexpression of wg and dpp. Because the resulting cell changes resemble those seen in vertebrate tumour cells, the researchers speculate that tumorigenesis could partly result from the uncoupling of apoptosis initiation and cell death.