BDNF and B-cell chronic lymphocytic leukemia: Immunoprecipitation (IP) demonstrated that NTSR2 interacted physically with TrkB in B-CLL cells, and this interaction was promoted upon BDNF stimulation, as demonstrated by the presence of phosphorylated TrkB (p-TrkB) in the NTSR2–TrkB immunocomplex (Figure 5f).