Figure 5.

Formation of germ cell tumors and carcinomas of different grades from PGCC-derived spheroids. (A) Hematoxylin–eosin (H&E)-stained images from xenografts formed by control Hey cells and PGCC-derived spheroids. (a) control Hey cells; (b) low-power view of multiple foci of dysgerminoma in a background of carcinoma; (c) high-power view of dysgerminoma showing vesicular nuclei and clear cytoplasm of tumor cells characteristic of primordial germ cells; (d) dysgerminoma with skeletal muscle differentiation; (e) mixed dysgerminoma and embryonic carcinoma; (f) dysgerminoma with mesenchymal morphology; (g) high-grade carcinoma; (h) mixed high- and low-grade tumor with high-power view; (i) benign squamous cells with immunohistochemical staining against cytokeratin. (B) H&E staining and IHC for SALL4, cytokeratin (CK) and OCT4 on continuous sections of xenografts formed by regular Hey cells (Control) and malignant germ cell tumors generated from spheroids derived from PGCCs. In control xenografts formed by regular Hey cells, cancer cells were positive for human-specific CK, but not for OCT4 and SALL4. In xenografts formed by PGCC-derived spheroids, all of the cancer cells were positive for human-specific CK, and there were clusters of cells positive for OCT4 and SALL4. Gray circles show the same subpopulations. Black cycle indicates cytokeratin positive cells. Scale bars, 50 μm.