HER-2/neu Testing and Therapy in Gastroesophageal Adenocarcinoma
Table 1
Consensus panel recommendations on HER2 scoring for gastric cancer [45, 58].
Reactivity characteristics
Score/classification
No reactivity or membranous reactivity in <10% of tumor cells
0/negative
Faint/ barely perceptible membranous reactivity in >10% of tumor cells; cells are reactive only in part of their membrane, in any where high magnification (×40) is required for unequivocal demonstration of membranous staining
1+/negative
Weak to moderate complete or basolateral membranous reactivity in >10% of tumor cells
2+/equivocal
Moderate to strong complete or basolateral membranous reactivity in >10% of tumor cells; only low magnification (×2.5–5) is needed to confirm strong staining intensity.
3+/positive
Biopsy (not surgery) samples with cohesive either IHC3+ and/or FISH+ clones (at least 5 cells) are considered positive irrespective of size, that is <10% of tumor area
3+/positive
FISH: fluorescence in situ hybridization; HER2: human epidermal growth factor receptor 2; IHC: immunohistochemistry.
