RET and neoplasm: Therefore, in addition to inhibition of VEGFR-2 tyrosine kinase and EGFR tyrosine kinase, inhibition of RET tyrosine kinase by ZD6474 may provide particular additional antitumour effects in the treatment of tumours with genetic changes in the RET gene (mutation or translocation) that lead to RET receptor signalling-dependent tumour cell growth (Santoro et al, 2002).