ERBB2 and breast cancer: <b>Results:</b> In a HER2-positive breast cancer cohort (<i>n</i> = 147) with baseline D-PET, deep learning (3D ResNet, AUC = 0.79) and radiomics (logistic regression, AUC = 0.78) achieved comparable performance on the primary test set, whereas the ITH model showed limited value (AUC = 0.61).