The promoter-specific expression of GluR6 isoforms in neuronal and non-neuronal cells was confirmed by performing RT-PCR of mRNAs isolated from brain tissue, normal fibroblasts, and 18 tumor cell lines representing breast carcinoma, prostate carcinoma, ovarian carcinoma, melanoma, astrocytoma, and glioblastoma. The gene discussed is GRIK2; the disease is breast carcinoma.