Aberrant activation of the MAPK pathway is a hallmark of several CNS tumors, frequently driven by genetic alterations such as point mutations, gene fusions, amplifications, or overexpression, most commonly involving RTKs, RAS, RAF, and regulators of the pathway such as SHP2 and NF1 [22,45,46] (Figure 2). The gene discussed is NF1; the disease is central nervous system neoplasm.