CD44 and neoplasm: Our findings indicate that the APP and collagen signaling pathways mediated by PRELP+ CAFs may inhibit immune cell function, promote immune evasion by tumor cells, remodel the ECM, and influence immune cell infiltration and activity through the APP-CD74 and collagen-CD44 axes (Chen et al., 2024; Cheung et al., 2025) (Figure 4c).