Similarly, when we tested selitrectinib, repotrectinib, and zurletrectinib against mouse glioma Bcan-Ntrk1 fusion-positive cell lines engineered by CRISPR to harbor the mouse orthologue single and double Trka resistant mutations (Trka G598R, Trka G670C, Trka G598R/G670A, and Trka G598R/G670C, respectively), all were highly active against the Trka G598R, and the Trka G598R/G670A but less so against the Trka G670C or the Trka G598R/G670C mutants (Fig. 2d, Supplementary Figs. 4b, c, and 5). Here, NTRK1 is linked to central nervous system cancer.