Human tissues for positive controls showed the expected staining patterns: for OCT4 (Supplementary Figure 1A) and NANOG (Supplementary Figure 1B) on seminoma, SOX2 (Supplementary Figure 1C) on skin, KLF4 (Supplementary Figure 1D) on breast carcinoma, and c-MYC (Supplementary Figure 1E) on colon. The gene discussed is POU5F1; the disease is seminoma.