SOX2 and seminoma: Positive staining was demonstrated on sections of control human tissues: tonsil for CD44 (Figure S2A), seminoma for OCT4 (Figure S2B) and NANOG (Figure S2C), skin epidermis for SOX2 (Figure S2D), breast carcinoma for KLF4 (Figure S2E), and colon mucosa for c-MYC (Figure S2F).