PCNA and central nervous system cancer: Besides this and contrary to what has been reported, Leaver et al. showed that γ-linolenic acid (GLA) decreased proliferation both in vitro (C6 glioma cell line and multicellular glioma spheroids prepared from cell lines) and in vivo (implanted C6 glioma cells in rats) models through MTT assay and proliferating cell nuclear antigen (PCNA) and Ki-67 stain, respectively [87].