The proposed model of bidirectional interaction between NTRK1-expressing neuroblastoma cells and Schwann cells is depicted in Fig. 5 illustrating potential mechanisms which might explain why differentiated neuroblastomas with high NTRK1 expression have an elevated Schwann cell content, whereas poorly differentiated tumors with low NTRK1 expression are only marginally infiltrated by their stromal cells. This evidence concerns the gene NTRK1 and neuroblastoma.