NTRK1 and neuroblastoma: TRAIL also induces apoptosis and abrogates the in vitro tumorigenic activity of NGF-activated TrkA expressing NB cells, via a mechanism that overcomes cFLIP-mediated resistance to TRAIL-induced apoptosis in the absence of NGF, adding a novel important pro-apoptotic immunological dimension to NGF/TrkA interactions in NB cells.