MAP2K7 and neoplasm: Heterogenenous GSCs, which is described as multiple GSC subtypes/subpopulations coexisting within a single tumor, is a major reason that multiple different pattern of signaling pathway are activated in GSCs, such as PI3K/AKT, MEK/ERK, JAK/STAT, WNT/β-catenin, NF-κB, and MAPK/p38 [60, 63].