Connective Tissue Oncology Society

2001 CTOS Annual Meeting—Oral Presentations

HER-2/NEU STAINING IN OSTEOSARCOMA: ASSOCIATION WITH INCREASED RISK OF METASTASIS
Holly Zhou, Rob Goldsby, R. Lor Randall, Lynn Smith, Cheryl M. Coffin
Departments of Pathology, Pediatrics, Orthopedics, and Radiation Oncology, University of Utah

OBJECTIVE: Her-2/ Neu expression in high grade osteosarcomas (OSC) has been proposed as an indicator of poor prognosis. This study correlates Her-2/ Neu staining in OSC with tumor progression and metastasis.

METHODS: Her-2/Neu expression in 22 pre-treatment OSC and 12 pulmonary metastatic OSC was assessed by standard immunohistochemical techniques on formalin-fixed paraffin embedded tissue. The Her-2/Neu staining pattern, outcome and pulmonary metastases were analyzed.

RESULTS: 10/22 pretreatment OSC displayed cytoplasmic Her-2/Neu reactivity in more than 25% of tumor cells. Among these, 70% (7/10) patients had pulmonary metastases (4 at presentation, 3 later). In addition, focal cytoplasmic Her-2/Neu reactivity with more intense staining in foci with chondroblastic differentiation was identified in 7/22 pre-treatment OSC. 5/7 patients in this group had pulmonary metastases in a minimal followup of 4 years. The pattern of Her-2/Neu staining in pulmonary metastic OSC is identical to that in primary OSC.

CONCLUSION: Cytoplasmic staining of Her-2/Neu in pre-treatment OSC correlates with increased risk of pulmonary metastasis. The Her-2/Neu positive cells may represent a chemoresistant, biologically aggressive subpopulation in OSC.