BDNF and central nervous system cancer: The role of HERV-W in schizophrenia is also know as it was reported that in recent-onset schizophrenia patients there is a high HERV reverse transcriptase activity and that overexpression of HERV-W env in U251 glioma cells alters dopamine D3 receptor (DRD3) and brain neurotrophic derived factor (BDNF) levels, both known to increase the risk for schizophrenia [139].