Singh et al. demonstrated that TrkA, the NGF receptor, acts as a tumor necrosis factor receptor-associated factor 4 (TRAF4)-targeted ubiquitination substrate to stimulate p38 MAPK activation and invasion-related gene expression and that inhibition of TrkA activity eliminated TRAF4-dependent prostate cancer cell invasion [37]. The gene discussed is NTRK1; the disease is prostate cancer.