Table 4.

Results of immunohistochemical studies

	PDGFR-α Staining		PDGFR-β Staining
Specimen	Tumor Cellsa	Blood Vesselsb	Tumor Cellsa	Blood Vesselsb	Response	PFS (Months)
1	2+	Few	3+	Some	PD	2
2	3+	All	3+	All	SD	9
3	3+	Few	3+	Some	SD	6
4	1+	All	1+	All	PD	<1
5	3+	Few	3+	Some	SD	7

Abbreviations: PDGFR, platelet-derived growth factor receptor; PFS, progression-free survival; PD, progressive disease; SD, stable disease.

^aExpression-level intensity in tumor vessels: 1+, faint but distinct; 2+, strong; 3+, very strong.

^bPercentage of tumor cells expressing protein: few, less than 5%; some, 10%–20%; all, >60%.