 Genetic aberrations targeting the Ras-mitogen-activated protein kinase MAPK signalling pathway are a hallmark molecular feature of Low Grade Gliomas including optic pathway gliomas and NF1 as well as some low-grade glial-neuronal tumours. The gene responsible for NF1 has been cloned and encodes a protein called neurofibromin. Loss of Neurofibromin is associated with elevated levels of Ras, and Activated Ras results in the initiation of a cascade of signalling events such as activation of Raf and MAPK that leads to increased cell proliferation. Thus MAPK inhibitors offer an attractive novel therapeutic option for both NF1 related PN and optic pathway gliomas 