Discovering differential protein expression caused by CagA-induced ERK pathway activation in AGS cells using the SELDI-ProteinChip platform

Table 2 Comparison of biomarkers’ expression level under mitogen-activated protein kinase kinase (MEK) inhibitor free, treated and DMSO treated conditions

Array	m/z	Inhibitor free		Inhibitor treated		DMSO treated		Comments
type		Fold change (W vs V)	P-value	Fold change (W+I vs V+I)	P-value	Fold change (W+D vs V+D)	P-value
SAX2	9084	1.64	0.021	1.00	0.827	2.21	0.021	Caused by ERK1/2 activation
CM10	4229	2.25	0.021	1.07	1.000	2.44	0.021
	8162	1.71	0.021	-1.15	0.149	1.81	0.021
SAX2	2013	-1.99	0.021	1.16	0.149	1.03	0.773	Have no relationship with ERK1/2 activation
	4286	-3.50	0.021	-2.14	0.021	-1.95	0.021
	6545	2.86	0.021	2.39	0.021	2.00	0.021
	8564	-3.05	0.021	-2.96	0.021	-1.85	0.021
	9952	-3.35	0.021	-2.87	0.021	-2.62	0.021
	11 643	-1.71	0.021	-2.49	0.021	-2.38	0.021
CM10	4714	1.89	0.021	1.68	0.043	1.74	0.021
	4729	1.99	0.021	1.72	0.021	1.86	0.021
	5130	1.67	0.021	1.66	0.021	2.91	0.021
	6656	2.12	0.021	2.31	0.021	2.44	0.021
	11 087	-1.72	0.021	-1.85	0.021	-1.52	0.021
	13 804	2.23	0.021	2.56	0.021	2.60	0.021
	14 021	1.98	0.021	1.79	0.021	1.61	0.021

Biomarkers listed in top three lanes were identified as biomarkers induced by extracellular signal-regulated kinase 1/2 (ERK1/2) activation. Columns 3, 5, 7 give fold changes in peak intensity in wild-type cagA transfectants (W) compared with vector transfectants (V) as reference under MEK inhibitor U0126 free, MEK inhibitor U0126 treated (I) and DMSO treated (D) conditions. Statistical P-value were calculated using a non-parametrical Mann-Whitney test (n = 4).