Four different types of human glioma cell lines (LNT-229, LNT-308, LNT-428, and G55) were treated with selective mGluR5 antagonist (MPEP), mGluR1-specific antagonist (CPCCOE), and group I mGluRs (mGluR1 and mGluR5) agonist DHPG as a negative control. This evidence concerns the gene GRM1 and central nervous system cancer.