The abnormal growth of prostatic epithelium is accompanied by increased TrkA expression and the induction of TrkC expression in epithelial cells. These results suggest that neurotrophins could be involved in the abnormal growth of the human prostate, acting through specific Trk signal-transducing receptors whose expression is regulated by androgens.

The pattern of expression of neurotrophins and neurotrophin receptors in the analysed tumours basically matches that of sympathetic neurones, adrenal chromaffin cells and paraganglionic cells, and suggests responsiveness of these cells to neurotrophins. Nevertheless, the function of TrkA and TrkC in regulating the biology of these tumours, if any, remains to be elucidated.