ERBB2 and neoplasm: Notably, 80.6% (4,768/5,919) of ERBB2mut tumors—including 84.7% (366/432) of NSCLC with T-DXd off-label ERBB2 mutations—did not exhibit ERBB2 co-amplification, suggesting that these may not be HER2 IHC 3+ and therefore would not be considered on-label for T-DXd according to the recent pan-tumor approval.