PDCD1LG2 and breast cancer: Western blot results showed that PD-L1 (Proteintech, Mouse Monoclonal| Catalog number: 66248–1-Ig, Fig. 3D) and PD-L2 (Proteintech, Rabbit Polyclonal, Catalog number: 18251–1-AP, Fig. 3E) were highly expressed in BC cells.