PDPN and osteosarcoma: The expression of PKIB, AIM2, and GZMA was significantly decreased in high metastatic osteosarcoma 143-B cells compared with low metastatic osteosarcoma U2OS cells; the expression of PDPN and RPL22L1 was higher in 143-B cells (Figure 3A, Figure S2); and the expression of MDM2 was slightly increased in 143-B cells (Figure S2), which was consistent with the bioinformatics analysis results.