Models of cancer come in a variety of forms, from cancer cell lines in culture to genetically modified mice. In between are a host of organisms that also contribute to our understanding of this disease. Yeast, for example, have added much to our knowledge of the cell cycle and the maintenance of cell polarity, whereas egg extracts from Xenopus laevis have helped our comprehension of biochemical pathways and protein modifications essential for normal cellular function. Work on Caenorhabditis elegans was crucial for our grasp of the genetic pathway that regulates programmed cell death, and research in Drosophila melanogaster has identified several pathways that are deregulated during cancer formation, including the Hippo tumour suppressor pathway. Whether results are generated by cell lines, yeast, mouse orthotopic tumour models or zebrafish the cumulative information from these models should help us to understand in greater detail the subtleties of cancer formation.