RAF1 and central nervous system cancer: When LRRC4 expression was induced in the human U251 glioma cell line, the Ras/p-c-Raf/ERK/MAPK and PI-3K/AKT signaling pathways were found to be down-regulated, which in turn inhibited cell proliferation and invasion [6], [7][.Functional studies of mouse LRRC4 (mLRRC4) determined that the gene was crucial for fetal brain development, as it mediated cell cycle progression and neuron and glia cell differentiation [2], [8].