EPOR and osteosarcoma: Compared with the <2.5-fold increase in the percentage of CD163+EPOR+ TAMs in osteosarcoma lung metastasis patients, the ≥2.5-fold increase in the percentage of CD163+EPOR+TAMs in osteosarcoma lung metastasis patients had a significantly shorter mDFS and mOS (40.5 vs. 29.4 months, P < 0.0001; and 42.0 vs. 35.2 months, P < 0.0001, respectively) (Figure 8(a) and Figure 8(b)).