Human endogenous retroviruses and cancer: Causality and therapeutic possibilities

Figure 1 Possible mechanisms by which human endogenous retroviruses contribute to oncogenesis. Human endogenous retroviruses (HERVs) transcripts or proteins may directly have tumor promoting properties. The long terminal repeat (LTR) elements can function as promotors or enhancers for nearby (proto-) oncogenes or growth factors. Especially Env proteins might attract regulatory immune cells and thus provide an immunosuppressive microenvironment. And finally, the Env proteins may be directly involved in the metastasizing process.