The genetic control of growth ensures that animals grow to reproducible siz
es and that tumourous growth is rare. This year, the regulation of organ gr
owth has been studied extensively in Drosophila imaginal discs, and a signa
lling pathway that regulates organ growth and size has been identified. Fur
thermore, the role of Drosophila homologues to human tumour suppressor gene
s and oncogenes in imaginal disc growth has been investigated.