LIF and amyotrophic lateral sclerosis: Leukemia inhibitory factor (LIF) is a cytokine in the IL-6 family that promotes survival of neurons and glia in several animal models of neurodegenerative disease, such as amyotrophic lateral sclerosis [34, 35], multiple sclerosis [36–42], spinal cord injury [43, 44], and stroke [45–47].