CD40 and osteosarcoma: Qian et al. suggested that P50-associated COX-2 extragenic RNA (PACER) expression was higher in clinical osteosarcoma tissues and osteosarcoma cell lines, and the overexpression of PACER promoted the proliferation and metastasis of osteosarcoma cells by activating the COX-2 gene in an NF-κB-dependent manner [29].