CD44 and neoplasm: Among the patterns of interactions in which tumour cells act as signal receivers, we found that the receptor pairs that were significantly enhanced in IBC tumour cell interactions were PTN-SDC4, PTN-NCL, MDK-SDC4, MDK-NCL, and LGALS9-CD44, and these receptor pairs highlighted that endothelial, mesenchymal, and myeloid cells actively interact with tumour cells (Fig. 5d).