Figure 1. Representative images of the two cohorts. (A) A case of cohort A showed concordant HER2 results between the two blocks with homogeneous HER2 3+ staining. A1, A1’, Block 1; A2, A2’, Block 2. (B) A case of cohort A showed concordant HER2 results between the two blocks with heterogeneous HER2 3+ staining. B1, B1’, Block 1; B2, B2’, Block 2. (C) A case of cohort B showed discordant HER2 results between both blocks with 3+ in block 1 and 0 in block 2. C1, C1’, Block 1; C2, C2’, Block 2. Magnification ×200.