Rearrangement of the tropomyosin-related kinase gene (TRKA) was first biologically characterized in 1986 in a colorectal carcinoma patient (20), when tropomyosin was found to be fused to an unknown DNA sequence that likely codes for a transmembrane RTK (TPM3-TRKA) (20). Here, NTRK1 is linked to colorectal carcinoma.