The MNA-specific p3/h3 group was also characterized by a very low expression of NTRK1, whereas the favorable tumour group p1/h1 showed the highest expression of NTRK1. TrkA (or NTRK1) is a well-known marker of favorable NB tumours and its expression has been linked to several cancer forms [56]. Here, NTRK1 is linked to neuroblastoma.