C. Elegans can develop tumors, but only in the germ line (gamete-producing) cells, which are the only stem cells. There are no adult somatic stem cells, i.e. no

C. Elegans can develop tumors, but only in the germ line (gamete-producing) cells, which are the only stem cells. There are no adult somatic stem cells, i.e. no ability for repair, so no mechanism for cancer growth in the body. That said, many of the pathways that are central to mammalian cancers are there in C. Elegans, which still makes it a valuable model organism for cancer research.