As illustrated in Figure 1, treatment with a receptor tyrosine kinase inhibitor, which blocks MAPK pathways, results in the cancer cells secreting ligands, which bind to receptors on the cancer cells themselves in an autocrine fashion or to CAFs, intratumor macrophages, and other cells in the tumor microenvironment (TME) in a paracrine fashion. This evidence concerns the gene NTRK1 and cancer.