In addition to roles in CNS development and function, glia are considered to be primary immune cells of the CNS that survey the CNS for neuronal damage, modulating inflammatory responses and engulfing debris or foreign material.39 The JNK pathway mediates glial engulfment activity in Drosophila,40, 41 raising the intriguing possibility that RasV12/pico stimulates glial phagocytosis of tissue damage caused by premalignant tumour cells. The gene discussed is MAPK8; the disease is neoplasm.