More specifically, the proposed definition for HER2 IHC score 1+ in this study was membranous staining in invasive tumor cells as either (1) faint intensity in ≥20% of cells regardless the circumferential completeness; (2) weak complete staining in ≤10%; (3) weak incomplete staining in >10% or (4) moderate incomplete staining in ≤10%. This evidence concerns the gene ERBB2 and neoplasm.