GRM1 and amyotrophic lateral sclerosis: Riluzole, an inhibitor of metabotropic glutamate receptor 1 (GRM1) signaling and an FDA-approved drug for amyotrophic lateral sclerosis (ALS) treatment, has been used in an already completed clinical trial (NCT00866840) evaluating riluzole in treating patients with stage III/IV melanoma [90]; its use combined with sorafenib is evaluated in phase I of a clinical trial in patients with advanced solid tumors (NCT01303341).