Together with our recent report [19], our data strongly support the findings by Peng et al. [15], who demonstrated enhanced neurotrophin levels and elevated expression of TRK receptors on skin and gut mast cells in patients with mastocytosis, and suggest that TRK signaling may contribute to the pathogenesis of mastocytosis and development of resistance to targeted therapies in SM. The gene discussed is BDNF; the disease is systemic mastocytosis.