BDNF and sarcoma: To determine whether the observed in vitro inhibition of sarcoma cell growth by Trk receptor inhibitors could be translated into in vivo antitumor activity, K252a was administered to athymic nude mice bearing tumor xenografts of MES-SA/Dx5 cells, which were chosen for these studies due to their high BDNF and TrkB expression levels and multidrug-resistant character that could be more severe model of uterine sarcoma for in vivo analyses.