VEGFR2 inhibition was already detectable at 0.3 mg/kg in both Pz-1 sensitive and resistant RET or TRKA-expressing tumours; therefore, although angiogenesis inhibition may contribute to the anti-tumour effect of the drug, alone it was not sufficient to blunt the growth of these highly aggressive tumours in the presence of Pz-1 resistant RET or TRKA mutants (Supplementary information, Figure S11). This evidence concerns the gene NTRK1 and neoplasm.