Similarly, in agreement with previous work showing that the tumor phenotype can be observed in tumor-bearing hydras that do not consistently have an altered microbiome (this is the case for SpB, but not Rob; Domazet-Lošo et al., 2014), our transplantation experiments do not support the hypothesis that the alteration in tentacles’ number could be caused entirely by bacteria. Here, SFTPB is linked to neoplasm.