Expression of leukemia inhibitory factor by cartilage-forming tumors of bone: An immunohistochemical study

Recent studies have implicated leukemia inhibitory factor in connective‐tissue metabolism involving the remodeling of bone and the destruction of cartilage tissue. This cytokine, which has also been implicated in the proliferation of solid tumor, is expressed by osteotropic tumor cell lines. The present study investigated the presence of leukemia inhibitory factor in cartilage tissue harvested from cartilage‐forming bone tumors. Immunohistochemical study showed that it was present in all benign enchondromas (n = 8) and malignant chondrosarcomas (n = 6) but not in control tissue (n = 3). The cytokine was localized in only cytoplasmic areas of cartilage cells. The number of stained cells ranged from less than 5% in enchondroma of the hand to more than 70% in grade‐III chondrosarcoma. Moreover, high levels of leukemia inhibitory factor were found in the primary culture of tumor tissues (n = 7). These results question the significance of leukemia inhibitory factor in tumor‐associated bone resorption and the potential role of this cytokine as a prognostic marker.