a. Activating mutations;b. GRM3 is mutated in 7% of human non-small cell lung cancer adenocarcinoma;c. GRM3 mutants are found in human melanoma cancers.a. Activating mutations;b. GRM8 is mutated in 8% of human squamous non-small cell lung cancer and melanoma cancers. Here, GRM3 is linked to non-small cell squamous lung carcinoma.