CTSK and rheumatoid arthritis: The majority of the examined genes, including the regulator of cell growth and proliferation MTOR; the autophagy marker ULK1; the apoptosis indicator caspase-3; the proinflammatory cytokines TNFα, IL-1β, IFNα, and COX2; and the proteases MMP-9 and cathepsin K, were significantly upregulated in a sample of RA patients (n = 16) at baseline compared to healthy subjects (Figure 1).