Considering leptin signals proopiomelanocortin (POMC) neurons of the hypothalamus through the hypothalamic signal transducer and activator of transcription 3 (STAT3) pathway to regulate appetite35, we observed elevated hypothalamic STAT3 phosphorylation level induced by high miR-204 sEVs-injected mice and tumour-bearing mice than their respective control mice (Fig. 3j). The gene discussed is LEP; the disease is neoplasm.