Most previous IHC definitions of LA and LB tumours include ER+ and/or PR+, with HER2 positivity defining LB, creating a population size of approximately 5–10% (Cheang et al, 2008; Nguyen et al, 2008; Millar et al, 2009b; Blows et al, 2010). Here, ERBB2 is linked to neoplasm.