STAT3 and glioblastoma: Leptin has been shown to upregulate various intracellular signaling pathways linked to excessive proliferation, growth, migration, and invasion in various glioblastoma cell lines (Figure 1) [8] including NF-κB, p38-MAP Kinase, JAK/STAT3 and PI3K/Akt/mTOR/P70S6K.