Table 1. Currently used HER-2 immunohistochemistry scoring system in gastric cancer depends on the available specimen.

SCORE TO REPORT	HER-2 RECEPTOR OVEREXPRESSION ASSESSMENT	SCORING PATTERN: SURGICAL SPECIMEN	SCORING PATTERN: SMALL ENDOSCOPIC BIOPSIES (AT LEAST 6-8 DIAGNOSTIC FRAGMENTS)
0	Negative	No reactivity or membranous reactivity in <10% of tumor cells	No reactivity in any tumor cell
1+	Negative	Faint/barely perceptible incomplete membranous reactivity in ≥10% of tumor cells	Tumor cell cluster with a faint/barely perceptible incomplete membranous reactivity irrespective of percentage of tumor cells stained
2+	Equivocal	Weak to moderate complete, basolateral or lateral membranous reactivity in ≥10% of tumor cells	Tumor cell cluster with a weak to moderate complete, basolateral or lateral membranous reactivity irrespective of percentage of tumor cells stained
3+	Positive	Strong complete, basolateral or lateral membranous reactivity in ≥10% of tumorcells	Tumor cell cluster with a strong complete, basolateral or lateral membranous reactivity irrespective of percentage of tumor cells stained

HER-2: human epidermal growth factor receptor 2.