HER-2 Evaluation in a Specific Gastric Cancer Population with the Highest Rate of Mortality in Spain

Table 1

Immunohistochemistry scoring for HER2 in gastric and gastrooesophageal junction cancer, by type of diagnostic specimen.

IHC	Surgical specimen	Biopsy specimen	HER2 overexpression interpretation
0	No reactivity or membranous reactivity in <10% of tumour cells	No reactivity or no membranous reactivity in any tumour cell	Negative
+	Faint or barely perceptible membranous reactivity in ≥10% of tumour cells; cells are reactive only in part of their membrane	Tumour cell cluster with a faint or barely perceptible membranous reactivity irrespective of percentage of tumour cells stained	Negative
++	Weak to moderate complete, basolateral, or lateral membranous reactivity in ≥10% of tumour cells	Tumour cell cluster with a weak to moderate complete, basolateral, or lateral membranous reactivity irrespective of percentage of tumour cells stained	Equivocal
+++	Strong complete, basolateral, or lateral membranous reactivity in ≥10% of tumour cells	Tumour cell cluster with a strong complete, basolateral, or lateral membranous reactivity irrespective of percentage of tumour cells stained	Positive