ERBB2 and breast carcinoma: Cases in this HER2 analysis were slightly less likely to have non-localized breast cancer at diagnosis; 32% of cases who contributed buccal samples that were included in the HER2 analysis had regional or distant-staged disease at diagnosis, whereas 37% of cases who refused to contribute a sample had non-localized disease (N = 356, P = 0.07 by Fisher's exact test).