KIT and systemic mastocytosis: As many as 93 % of SM cases may harbor an activating D816V mutation in the catalytic domain of KIT (Garcia-Montero et al. 2006; Quintas-Cardama et al. 2011; Akin and Metcalfe 2004), a receptor tyrosine kinase expressed on the surface of mature mast cells and mast cell precursors (Lammie et al. 1994; Valent et al. 2003).