Figure 2

Cases with discordant judgment of HER2 score between CNB and surgically resected specimens. A-B. Case 54: HER2 score was 3+ for the CNB specimen (A) but 0 for the surgically resected specimen (B). The tumor had heterogeneous HER2 expression, and >30% of the area showed a strong membrane immunoreaction in the CNB specimen, whereas most of the area in the surgically resected specimen was HER2-negative. C-D. Case 84: HER2 score was 0 for the CNB specimen (C) but 2+ for the surgically resected specimen (D). This difference might have been due to suboptimal processing of CNB specimens or intratumor heterogeneity. E-F. Case 92: HER2 score was 2+ for the CNB specimen (E) but 3+ for the surgically resected specimen (F). Because the CNB specimen contained only a small amount of invasive component, the evaluation of HER2 was difficult. G-H. Case 94: HER2 score was 2+ for the CNB specimen (G) but 3+ for the surgically resected specimen (H). Processing of the CNB specimen might have been suboptimal, or the tumor may have been borderline in nature. Immunoperoxidase reaction, original magnification ×200.