IL6 and bone sarcoma: In a study by Rutkowski et al., elevated serum levels of a variety of cytokines including IL-8, IL-6 (interleukin-6), IL-1 (interleukin-1) and TNFR1 (Tissue Necrosis Factor Receptor 1) were linked to tumor extent and poor prognosis in adult patients with bone sarcomas [37].