Type of resistance

Mechanism

Target resistance

Mutation—a new KIT or PDGFRα point mutation and protein activation

KIT genomic amplification

Overexpression of the KIT oncoprotein, without a new point mutation

Target modulation

Activation of an alternate receptor tyrosine kinase protein, accompanied by loss of KIT oncoprotein expression

Functional resistance

KIT or PDGFRα activation, outside the juxtamembrane hotspot regions, in the absence of a secondary point mutation