ERBB2 and neoplasm: The proportion of HER2-positive cases reported previously has varied from 4.2 to 81.8% (Ito et al, 2001; Aishima et al, 2002; Ukita et al, 2002; Altimari et al, 2003; Nakazawa et al, 2005), and the discrepancy may be due to differences in staining procedure or tumour location.