Abstract 5332: Evaluation of GD2 expression in patients with osteosarcoma

GD2 is a disialoganglioside that is expressed on the cell surface in specific normal and malignant human tissues. Tumor specific cell surface antigens serve as important targets in cancer therapy. Anti-GD2 therapy using antibodies targeted to the cell surface antigen GD2 to induce antibody-dependent cellular cytotoxicity has been proven effective in treating GD2 expressing tumors like neuroblastoma and melanoma. Prior studies of osteosarcoma have shown GD2 to be expressed in malignant cells of osteosarcoma patients. In this study, the expression of GD2 in osteosarcoma will be evaluated further. A previously created and described tissue microarray was stained with 14.G2a, a murine monoclonal anti-GD2 antibody that was obtained from the National Cancer Institute. The intensity and location of tissue staining were assessed by a comparison between the positive and negative control slides. To evaluate GD2 expression quantitatively a cell-based ELISA was performed on different osteosarcoma patient derived cell cultures. The results of the tissue microarray showed that 34.8% of patient samples stained positive for GD2 while 60.9% of samples showed intermediate staining and only 4.3% of samples showed negative staining for GD2 (n=88). Nearly all of the osteosarcoma cell lines (n=24) showed levels of GD2 expression comparable to the neuroblastoma and fibrosarcoma cell lines and in some cases GD2 expression was significantly greater. Anti-GD2 therapy has been proven effective in treating patients with neuroblastoma and melanoma. The findings in this paper indicate that osteosarcomas express GD2 to a similar extent as neuroblastomas. These results would suggest clinical trials are worthwhile to further evaluate the benefit of anti-GD2 therapy in patients with osteosarcoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5332. doi:10.1158/1538-7445.AM2011-5332