Table 2.

Evaluation of immunostaining for EGFR and HER2.

Classification	IHC Score	EGFR	HER2
Negative	0	No staining or background type staining	No staining or <10%
Negative	1+	Discontinuous membrane staining; >10%	Faint/barely perceptible >10%
Equivocal	2+	–	Weak to moderate; complete or basolateral membrane staining; >10%
Positive	2+	Weak to moderate; >10%	IHC2+ and FISH+
Positive	3+	Moderate to strong; complete membrane staining; >10%	Moderate to strong; complete or basolateral membrane staining; >10%

IHC, immunohistochemistry; FISH, fluorescence in situ hybridization.