NTRK1 and neuroblastoma: We surveyed our seven neuroblastoma cell lines for NTRK1,2,3 expression and demonstrated enhanced mRNA levels for NTRK2 and NTRK3 in all tested cell lines (Figure 2G, 2H) , as well as enhanced NTRK1 expression in 5 of 7 experimental cell lines (Figure 2F).