Astrocytoma cell lines have a very low-endogenous ADAR2 editing activity as measured by editing of endogenous substrates such as GluR-B and GluR-6 transcripts.18 Therefore, we used the astrocytoma cell lines (U118 and A172), both untransfected or transfected with the pEGFP-ADAR2 construct or with pEGFP as a negative control. This evidence concerns the gene GRIK2 and astrocytoma (excluding glioblastoma).