In GBC, HER2 amplification (27.2%) transfers HER2 to dendritic cells via tumour-derived exosomes, inhibiting DC maturation and antigen presentation (19), whereas SMAD4 inactivation in eCCA (11.3%) hyperactivates TGF-β signalling to directly promote Treg differentiation and collagen deposition by CAFs (20, 21). This evidence concerns the gene ERBB2 and neoplasm.