SEMA3F and neoplasm: Id2 also seems to play a crucial role in tumor cell migration and invasion: indeed, c-Myc up-regulation and subsequent Id2 overexpression in highly metastatic human tumor cell lines lead to down-regulation of semaphorin 3 F (SEMA3F) that is a potent metastasis inhibitor and a direct target gene of the E47/Id2 pathway [281, 282].