CD274 and neoplasm: Similarly, Rodriguez et al. [68] showed that the increased expression and secretion of α-2,3 Sia in the TMEs of patients with PDAC promoted Siglec-9 receptor activation by upregulating CD206 and PD-L1 and immunosuppressive factors such as IL-10 and IL-6 monocyte polarization and differentiation to produce immunosuppressive TAMs, thereby promoting tumor progression and metastasis.