Extracellular factors including cytokines and proteins could regulate EMT process by multiple receptor mediated signaling pathways, such as transformation growth factor receptor and tyrosine kinase receptors, which accept signal came from epidermal growth factor and filamentary growth factor etc. IL-8 could also be used as a stimulating factor and combined with IL8R that located on cell membrane to promote tumor cell occurrence of EMT [34]. This evidence concerns the gene NTRK1 and neoplasm.