Moreover, we identified recurrent copy number gain/amplification involving several receptor tyrosine kinases (RTK), including amplification and protein over-expression of FGFR1. In vivo drug evaluation using a small molecule inhibitor (AZD4547) of FGFRs showed significant growth inhibition in the carcinosarcoma PDX tumor with the highest FGFR1 amplification and protein expression whereas AZD4547 showed no significant growth effects on carcinosarcoma lacking high level FGFR1 amplification, indicating oncogenic dependency on the amplified RTK pathway. This evidence concerns the gene NTRK1 and carcinosarcoma.