ERBB2 and breast cancer: To confirm our observation that at least in some breast cancers apparent HER-2 gene amplification without HER-2 over-expression is due to incomplete, or unproductive, amplification of the smallest amplified HER-2 region, we examined an independent set of primary breast tumor data from The Cancer Genome Atlas Project (TCGA) and a panel of established breast cancer cell lines from SU2C (Stand up to Cancer) (Heiser et al. [2012]).