TNFRSF9 and neoplasm: In addition, we observed increased interactions between macro-C3-SPP1 and Treg-C2-TNFRSF9 through the SPP1-ITGA4 axis in the MI group (Figure 9D, S10D), which could facilitate the adhesion and migration of activated Tregs within the tumour microenvironment, potentially contributing to immune suppression and tumour progression 50.