Figure 3

Representative images of immunohistochemical staining of primary osteosarcoma with HLA Class I EMR8-5 Sections: a, b, c and d: Sections from cases showing strongly positive expression of HLA class I with diffuse staining in > 50% of tumor cells in a conventional osteosarcoma (a, b: immonoperoxidase x 400 and x200 respectively) and chondroblastic osteosarcoma with well evident membranous immunostaining of malignant cells (c, d: immonoperoxidase x400). e and f: Sections from cases with low positive and heterogeneous expression of HLA class I, respectively, showed areas with both strongly positive and negative expression of HLA class I (immonoperoxidase x200). g: Sections from a case with negative expression of HLA class I (immonoperoxidase × 200).