Abstract
Summary Statement
RANK is expressed in 18% of human osteosarcomas and is likely to provide additional prognostic information for clinical purposes in osteosarcoma patients at the time of diagnosis.
Introduction
The receptor activator of nuclear factor kappa (RANK), a member of the tumor necrosis factor family, is activated by its ligand and regulates the differentiation of osteoclasts and dendritic cells. Local growth of osteosarcoma involves destruction of the host bone by osteoclasts and proteolytic mechanisms. Although prognosis of osteosarcoma has been improved by chemotherapy during the last decades, the problem of non responders and the lack of prognostic markers remains. It is the aim of this study to investigate the prognostic and predictive value of RANK expression in human osteosarcoma.
Patients & Methods
The expression of RANK was examined immunohistochemically in biopsies of 43 patients (mean age 25.7 years) with high grade osteosarcoma and the results were correlated with histologic response to chemotherapy, disease free and overall survival. Tumors with more than 40% positive osteosarcoma cells were scored positive.
Results
In 8 of 43 (18%) osteosarcoma specimens RANK expression could be dedected, the rest were negative. RANK expression showed a statistically significant correlation with overall survival of patients. 7/8 patients with RANK expressing tumours died, whereas only one in the negative group (88% in RANK positive tumours versus 37%; p<0.05). No significant difference was found when comparing RANK expression status with response to chemotherapy; 50% had a poor and 50% had a good response in RANK positive and 30,3% had a good and 69,7% had a bad response in RANK negative osteosarcomas. The appearance of metastases did not correlate with RANK expression status (37,5% metastases in RANK positive tumours versus 28,6% in negative).
Discussion/Conclusion
In conclusion our findings suggest that RANK is likely to provide additional prognostic information for clinical purposes in osteosarcoma patients at the time of diagnosis.
