PDCD1LG2 and osteosarcoma: To examine the effect of PD-L2 on proliferation, migration, and invasion of osteosarcoma cells, KHOS and U2OS cells were transfected with short hairpin RNA (shRNA) targeting PD-L2, and PD-L2 expression was subsequently detected by western blotting (WB) and real-time PCR (Fig. 2c).