Hormones are also involved in the close connection between sleep and tumors: ghrelin, related to an increase in tumor progression and a reduction in survival, could act on orexinergic neurons by activating them; leptin, involved in the proliferation of cancer cells, can induce the production of IL-6 and TNF-α; moreover, it seems to activate hypothalamic neurons, in turn connected with orexinergic neurons. The gene discussed is TNF; the disease is neoplasm.