Table 4.

Genetic aberrations and their possible significance in GIST

Gene	Specific aberrations	Potential clinical significance and prognosis
	Exon 11 deletions	Independent adverse prognostic factor in patients with GIST
	Exon 11 mutations	Independent predictors for disease-free survival, mixed histologic pattern; more frequent liver metastasis; poor prognosis for gastric GIST (pre-imatinib)
KIT	Exon 11 duplication	Characteristic site: almost exclusively in gastric GIST
	Exon 9 mutation	Characteristic site: almost exclusively in small intestinal GIST
	Deletion of 557–558 codon	Prognostic value in choosing imatinib therapy
	LOH	Possible role in liver metastasis
PDGFR	Exon 18 mutation	Imatinib resistance
	p16, p14 low mRNA expression	Associated with aggressive clinical behavior and unfavorable prognosis
CDKN2A tumor suppressor pathway	CKK4, RB1, MDM2, TP53, E2F1 high mRNA expression	Associated with aggressive clinical behavior and unfavorable prognosis
	Upregulation of E2F1	Increased cell proliferation and adverse prognosis in GIST
P16	Negative expression	Worse prognosis and 2.3-fold relative increased risk of dying of disease
Hox11L1	LOH	Worse tumor-specific and relapse-free survival rates

GIST, gastrointestinal stromal tumors; LOH, loss of heterozygosity