Table P1.

Overview of phenotypes in mice with Kit mutations and their sensitivity to targeted kinase inhibition

	Kit kinase mutation status
	Wild type	Loss of function	Primary gain of function (V558Δ allele)	Second-site double mutation (V558Δ;T669I allele)
Interstitial cells of Cajal	+	-	++ (hyperplasia)	+++ (hyperplasia)
Gastrointestinal stromal tumor	-	-	++	+
Mast cell numbers	+	-	++	+++
Red blood cell development	+	- (macrocytic anemia)	+	+++ (microcytic erythrocytosis)
Kinase sensitivity to imatinib/dasatinib in vivo	+	NA	++	− (resistance)
Kinase sensitivity to sunitinib/sorafenib in vivo	+	NA	++	++

+, present/normal; ++, increased; +++, greatly increased; - absent/impaired; NA, not applicable.