title: Overexpression of metastatic tumor antigen in osteosarcoma: comparison between conventional high-grade and central low-grade osteosarcoma.
abstract: OBJECTIVE
  The metastatic tumor antigen (MTA) gene is a recently identified metastasis-associated gene which has implications in the signal transduction or regulation of gene expression. However, the expression of MTA in osteosarcoma and its potential relationship with metastasis have not been examined, forming the basis of this study.
  
  
  METHODS
  We compared the expression levels of the MTA1 protein between 32 cases of high-grade osteosarcomas and 21 cases of low-grade osteosarcomas by immunohistochemistry. In addition, the mRNA expression levels of MTA1, 2, 3 in these osteosarcoma cell lines and control fibroblasts were evaluated by real-time quantitative PCR.
  
  
  RESULTS
  MTA1 immunoreactivity was present in 81.25% of high-grade osteosarcoma specimens. Its expression was predominantly localized to the nucleus or cytoplasm of osteosarcoma cells. Thirteen (86.6%) of 15 patients who died of osteosarcomas displayed strong MTA1 expression. Both primary bone and pulmonary metastatic lesions exhibited MTA1 expression. All low-grade osteosarcomas were negative for MTA1 except for focal weak reactivity in two cases. The tested high-grade osteosarcoma cell lines showed marked amplification of MTA1 and MTA2 mRNA compared to control cells.
  
  
  CONCLUSIONS
  These results suggest that MTA might be involved in the progression of high-grade osteosarcoma, particularly in hematogenous metastasis of osteosarcoma.
authors: Department of Pathology, College of Medicine, Hallym University, Anyang, Korea.
authors: Hye-Rim
authors: HR
authors: Park
authors: Woon Won
authors: WW
authors: Jung
authors: Hyun Sook
authors: HS
authors: Kim
authors: Patrizia
authors: P
authors: Bacchini
authors: Franco
authors: F
authors: Bertoni
authors: Yong-Koo
authors: YK
authors: Park