Likewise, our earlier study demonstrated the presence of GluR5 in U343 glioma cells, whereas GluR6, GluR7, KA1 and KA2 subunits were found in all 12 analyzed cancer cell lines, which suggests a role of kainate receptors in metabolism and proliferation of cancer cells (Stepulak et al. 2009). This evidence concerns the gene GRIK4 and cancer.