TT and MZ-CRC-1 (MTC cells harbouring RET C634W and M918T mutants, respectively), TPC-1 (PTC cells harbouring the CCDC6-RET fusion), Lc-2/ad (NSCLC cells harbouring the CCDC6-RET fusion) and KM12 (CRC cells harbouring the TPM3-TRKA fusion) were selected to explore the ability of Pz-1 to inhibit RET- and TRKA-derived oncoproteins in human cancer cell lines endogenously harbouring oncogenic versions of the two RTKs. This evidence concerns the gene NTRK1 and medullary thyroid gland carcinoma.