Abstract
There are no reports of cancer in sponges, despite them having somatic cell turnover, long lifespans, and no specialized adaptive immune cells. In order to investigate whether sponges are cancer resistant, we exposed a species of sponge, Tethya wilhelma, to X-rays. We found that T. wilhelma can withstand 518 Gy of X-ray radiation. That is approximately 100 times the lethal dose for humans. A single high dose of X-rays did not induce cancer in T. wilhelma, providing the first experimental evidence of cancer resistance in the phylum Porifera. Following X-ray exposure, we found an overexpression of genes involved in DNA repair, signaling transduction pathways, and epithelial-to-mesenchymal transition. T. wilhelma has the highest level of radiation resistance that has yet been observed in animals that have sustained somatic cell turnover. This may make them an excellent model system for studying cancer resistance and developing new approaches for cancer prevention and treatment.