Table 2.

Phosphorylated extracellular signal-regulated kinase (pERK1/2) and pAKT expression before and during the second week of imatinib treatment

Patient	pERK1/2 expression		pAKT expression		Change in expression					Clinical Response	Mutation
	pERK Baseline	pERK 2nd week	pAKT Baseline	pAKT 2nd week	pERK1/2	pAKT	C-KIT	PDGFR-α	PDGFR-β		NRAS	BRAF
1	+2	+1	0	+1	↓	↑	↓	--	↓	PD	N/A	N/A
2	0	0	0	N/A	--	N/A	--	--	↓	SD	WT	V600E
3	+3	+3	0	+3	--	↑	--	--	--	PD	WT	V600E
4	0	0	+2	+1	--	↓	--	--	↓	PR	WT	WT
5	N/A	N/A	+3	N/A	N/A	N/A	↓	↓	↓	PD	WT	V600E
6	+1	+2	+2	0	↑	↓	--	↓	--	PD	WT	V600S
7	0	0	+1	+1	--	--	↑	--	↑	PD	WT	WT
8	0	0	0	+2	--	↑	↑	--	↑	PD	WT	V600E
9	N/A	N/A	+1	0	N/A	↓	↓	↓	↓	PD	Q61R	V600E
10	+3	+2	0	0	↓	--	↓	↓	↓	SD	WT	V600E
11	0	0	+1	+2	--	↑	↑	↓	↓	PD	WT	V600E
12	0	0	N/A	N/A	--	N/A	--	--	--	SD	WT	V600E

Changes in the expression of C-KIT and platelet-derived growth factor receptor (PDGFR)–α and –β were previously published [7]. Numbers indicate percentage of cells staining positively for pERK1/2 or pAKT (0, 0–5%; 1+, 6–25%; 2+, 26–75%; 3+, >75%). ↑, increase in protein expression during treatment; ↓, decrease in protein expression during treatment; --, no change in protein expression during treatment; N/A, no tissue available for analysis; PD, progressive disease; PR, partial response; SD, stable disease; WT, wild type.