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

Recent studies have implicated leukemia inhibitory factor in connective-tis sue metabolism involving the remodeling of bone and the destruction of cart ilage tissue. This cytokine, which has also been implicated in the prolifer ation of solid tumor, is expressed by osteotropic tumor cell lines. The pre sent study investigated the presence of leukemia inhibitory factor in carti lage tissue harvested from cartilage-forming bone tumors. Immunohistochemic al 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 cy tokine was localized in only cytoplasmic areas of cartilage cells. The numb er 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 leukemi a 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.