Kit and melanocyte migration.

As described in this issue, Alexeev and Yoon introduced a Kit-activating mutation into melanocytes. Although mitogenic in mast cells, this mutation was motogenic in melanocytes. Further, melanocytes had a reduced proliferative rate and were less differentiated. The disparate response may be due to differences in the cellular milieu of melanocytes and may have implications for normal melanocytic integration into the epidermis, nevogenesis, and melanoma.