KIT and cancer: KIT plays an important role in the development of gametes,bloodcells, mast cells, and melanocytes.2 Lossof function mutations cause the autosomal dominant condition, piebaldism,which is characterized by loss of pigmentation of the skin and hair.9 Gain of function mutations are found in severaltypes of cancers, including gastrointestinal stromal tumors, acutemyelogenous leukemia, systemic mastocytosis, and germinomas.10−18