In addition to oncogenes and tumor suppressor genes, most cancers acquire several other key mutations that enable cancer to progress. While researchers don't yet know all the mutations involved, they have organized them in terms of their activities in support of tumor growth and metastasis. In addition to the contributions of oncogenes and mutated suppressor genes, additional genomic mutations enable the invasion of neighboring tissue, evasion of immune system detection, recruitment of a new blood supply, dissemination and targeting of new sites, and the penetration and reinvasion through new blood and tissue layers. Over time, successful metastasis occurs.