HER2 Status in Premalignant, Early, and Advanced Neoplastic Lesions of the Stomach
Table 1
Immunohistochemical criteria for HER2 scoring in neoplastic specimens of the stomach.
Surgery
Biopsy
HER2 score
No reactivity or membranous reactivity in <10% of tumor cells
No reactivity in any tumor cell
Negative (0)
Faint or barely detected membranous reactivity in ≥10% tumor cells
Tumor cell cluster of ≥5 cells with faint or barely detected membranous reactivity irrespective of percentage of tumor cells stained
Negative (1+)
Weak to moderate complete, basolateral, or lateral membranous reactivity in ≥10% tumor cells
Tumor cell cluster of ≥5 cells with weak to moderate complete, basolateral, or lateral membranous reactivity irrespective of percentage of tumor cells stained
Equivocal (2+)
Strong complete, basolateral, or lateral membranous reactivity in 10% or more of tumor cells
Tumor cell cluster of ≥5 cells with strong complete, basolateral, or lateral membranous reactivity irrespective of percentage of tumor cells stained
