Currently, using the teratoma model, we analyzed differentiation of wild type, i.e., Pax7+/+ ESCs (ESC lines B3, B5, B8), and ESCs lacking functional Pax7 gene, i.e., Pax7−/− ESCs (ESC lines B4, AI7.15, T2M4). The gene discussed is PAX7; the disease is teratoma.