Interestingly, in PAAD, PTPN2 expression was associated with these immune checkpoint markers, including CD274 (PD-L1), CTLA4, HAVCR2, LAG3, PDCD1, PDCD1LG2, TIGIT and SIGLEC15 (Figure 12C). Here, SIGLEC15 is linked to pancreatic adenocarcinoma.