The parameters that predicted HER2 cluster 2 (equivalent to score 1+) were faint complete staining at ≥ 20% of invasive tumour cells and/or faint incomplete staining in ≥ 20%, weak complete staining in ≤ 10%, weak incomplete staining in > 10% and moderate incomplete membranous staining in ≤ 10% of invasive tumour cells. This evidence concerns the gene ERBB2 and neoplasm.