Aktipis et al. (2015) searched for cancer in all lineages containing multicellular organisms and found cancer or cancer‐like disease in all but five lineages: Choanoflagellata, unicellular organisms that form simple multicellular colonies; Ctenophora and Placozoa, two groups of primitive organisms which lack many components involved in traditional neoplastic pathways; Porifera, which have no distinct tissues or organs, and some of which have a cell‐shedding mechanism used to remove damaged cells; and Hemicordata, which like elephants bear additional copies of TP53. The gene discussed is TP53; the disease is cancer.