In osteonecrosis, elevated FSTL1 promotes NF-κB-dependent cytokine release and tissue degradation (Qu et al., 2019), while in infections and chondrocytes, it drives inflammation via TLR4/NF-κB and MMP induction (Hu et al., 2019; Chen and Liu, 2019). The gene discussed is TLR4; the disease is infection.