SHAP analysis highlighted Wavelength-HHL_GLSZM_SAHGE and DLfeature_8 as key HER2 predictors.<h4>Conclusion</h4>By integrating clinical, endoscopic, and radiomic data, the hierarchical multimodal approach enhances HER2 expression prediction in GC, thereby optimizing clinical decision-making, and enabling tailored HER2-targeted therapies. The gene discussed is ERBB2; the disease is gastric cancer.