Table 2.

Correlation between EGFR protein expression and gene variation

	EGFR-FISH result
EGFR-IHC	FISH positive			Amplification
	No	Yes	P	No	Yes	P
System 1			0.034			0.001
L	39	10		9	0
M	25	14		37	2
H	3	5		3	5
System 2			0.036			0.015
L	34	8		42	0
H	31	21		47	7
System 3			0.120			0.006
L	37	11		48	0
H	30	18		41	7
System 4			0.038			0.001
L	64	24		86	2
H	3	5		3	5
System 5			0.674			0.299
L	9	3		12	0
H	58	26		77	7
System 6			0.175			0.027
L	11	3		14	0
M	26	7		33	0
H	30	19		42	7
Total	67	29		89	7

System 1–6, EGFR-IHC scoring system 1–6

L, low level of EGFR expression; M, intermediate level; H, high level

FISH positive, EGFR gene amplification or high polysomy