In contrast, the silencing of GluR2 by siRNA transfection increased glioma cell proliferation (Beretta et al. 2009), whereas gene silencing of GluR4 modulated the mRNA expression of various tumor-suppressor genes, oncogenes and other genes involved in invasion, adhesion and metastatic capabilities, which resulted in significant increase of cell viability of human rhabdomyosarcoma/medulloblastoma (TE671) and human multiple myeloma RPMI8226 cells. This evidence concerns the gene GRM2 and central nervous system cancer.