IHC score

Criteria

0 (Negative)

No reactivity/Reactivity in ≤10% tumour cells

1+ (Negative)

Faint weak reactivity in >10% of tumour cells but only a portion of the membrane is positive

2+ (Equivocal)

Weak to moderate complete membrane reactivity in >10% of tumour cells or circumferential intense membrane staining in ≤30% of cells

3+ (Positive)

>30% of tumour cell must show circumferential intense and uniform membrane staining. A homogenous (Chicken wire) pattern should be present