GRN and glioblastoma: We transduced wild-type and GRN-KO HepG2 (hepatoma cell line) and U87 (glioblastoma cell line) cells with these different truncated PGRN-expressing lentiviruses and assessed the performance of the cells in cell-based tumorigenicity assays, such as colony formation, migration, and proliferation, both in normal cell culture media and in media with reduced serum concentration (Fig. 1C).