Table 1.

Recommendation for scoring the HER2-stained tissue sample [5]

Score = 0/1+	Score = 2+	Score = 3+
No membrane staining or incomplete membrane staining in < 10% of invasive tumour cells (0+) or faint/barely perceptible or weak incomplete membrane staining in > 10% of tumour cells (1+) Clinical Significance—negative	A weak to moderate complete membrane staining is observed in > 10% of tumour cells or strong complete membrane staining in ≤ 10% of tumour cells Clinical significance—equivocal or borderline	A strong (intense and uniform) complete membrane staining is observed in > 10% of invasive tumour cells Clinical significance—positive