GRM1 and melanoma: Tg(Grm1)/Cyld−/− mice autochthonously developed melanoma mainly on the tail and ears (Figure 3A), due to an increased expression of the metabotropic glutamate receptor 1 (GRM1) under the control of the melanocyte specific Dct (Trp-2) promoter, and a lack of the tumor suppressor cylindromatosis (CYLD) [26].