Giant cell tumor of bone can be locally aggressive and occasionally can metastasize in the lungs. To identify new markers predictive of aggressive behavior, we analyzed five patients who developed lung
metastasis and five who remained disease free for a minimum of 5 years. Using two-dimensional electrophoresis, we detected 28 differentially expressed spots. Fourteen spots were identified using mass spectrometry, including seven up-regulated and seven down-regulated in metastatic samples and classified according to functional categories. We then selected five
proteins involved in cell cycle or apoptosis.
Thioredoxin peroxidase, allograft inflammatory factor 1, and
ubiquitin E2N had more than threefold up-regulation;
glutathione peroxidase 1 had 1.9-fold up-regulation; and
heat shock protein 27 showed down-regulation in metastatic samples with a very low P value. After validation and analysis of
protein levels, evaluation of clinical impact was assessed in a much wider cohort of primary archival specimens. Immunodetection showed a higher frequency of
thioredoxin peroxidase, allograft inflammatory factor 1,
ubiquitin E2N, and
glutathione peroxidase 1 overexpression in primary
tumors that developed into lung
metastases or that locally relapsed than in the disease-free group, with variable
stain intensity and distribution. Kaplan-Meier analysis showed that high expression of
glutathione peroxidase 1 was strongly related to local recurrence and
metastasis, suggesting that its up-regulation may identify a subset of high-risk patients with
giant cell tumor prone to receive diverse clinical management.