Table 5. Clinical response of advanced GISTs to imatinib 400 mg correlated with mutational status (34).

Genotype	Percentage of cases	Imatinib response
CD117 exon 11 mutation	70%	85%
CD117 exon 9 mutation	15%	45%
CD117 exon 13 mutation	<5%	Some (few cases)
CD117 exon 17 mutation	<5%	Some (few cases)
PDGFRA D842V mutation	4%	None
PDGFRA other mutations	1%	Some (few cases)
No CD117 or PDGFRA mutation	5–10%	Little

GIST, gastrointestinal stromal tumor.