In non-neuronal cancer cells, genomic and proteomic studies have revealed glutamate receptor mutations and aberrant glutamatergic signaling related to iGluRs, mGluRs, and their downstream effectors.258,262 Known to be absent in normal melanocytes,263,264 mGluR1 was detected in 7 out of 19 biopsies from melanoma patients, and in 12 out of 18 melanoma cell lines.264 These findings suggested a potential role for mGluR1 in melanoma progression. This evidence concerns the gene GRM1 and cancer.