Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China Background: Galectin-1 is an immunoregulatory protein which was expressed in the activated pancreatic stellate cells (PSCs). Aim: This study was to investigate the relationships between galectin1 expressed in PSCs and T cells in pancreatic cancer. Methods: Immunohistochemistry was performed in 66 pancreatic cancer and 10 normal pancreas tissues to detect the galectin-1 and CD3 expression. The relationship between galectin-1, CD3 and clinicopathologic variables was assessed. Expression of galectin-1 in freshly isolated PSCs fromhumannormal pancreas (hNPSCs) and human pancreatic cancer tissues (hCaPSCs) were evaluated bywestern blot and quantitative RT-PCR. The apoptosis of Tcells coculturedwith these PSCswere detected byflowcytometry and Tcell IL-2, IL-4, IL-5 and INF-g production levels were quantified by ELISA. Results: Galectin-1 was higher expressed in pancreatic cancer compared to normal pancreas (P<0.05). Galectin-1 expression was gradually increased in well, moderately, poorly differentiated pancreatic cancer (P<0.05, separately), while the CD3 expression is decreased (P<0.05, P<0.01). Galectin-1 expression was associated with tumor size (p1⁄40.007), lymph node metastasis (p1⁄40.019), differentiation (p1⁄40.021) and UICC stage (p1⁄40.01). CD3 expression was associated with tumor differentiation (p1⁄40.009) and UICC stage (p1⁄40.018). Expression of Galectin-1 (p<0.001) and CD3 (p1⁄40.002) were associated with short patient survival. In vitro coculture experiments showed that, compared with hNPSCs, hCaPSCs inducedmore apoptosis of CD3 Tcells, more secretion of Th2 cytokines (IL4 and IL-5) and less secretion of Th1 cytokines (IL-2 and INF-g) (p<0.01). Conclusions: The high expression of galectin-1 in hCaPSCs enhance the apoptosis and anergy of T cells in pancreatic cancer, and thus may play a role in immune evasion of pancreatic cancer.