PAK4 and osteosarcoma: In 23 osteosarcoma patients who received adjuvant chemotherapy, the expression of PAK4 (OS; p = 0.033, RFS; p = 0.016) and PD-L1 (OS; p = 0.029, RFS; p = 0.019) was significantly associated with both overall survival and relapse-free survival (Figure 1d).