(A) Expression of undifferentiated cell specific markers by immunostaining for OCT4 (red nuclear staining, merged onto Hoechst (blue)), for the cell surface marker Tra 1–60 (red, merged onto Hoechst (blue)); and (B) for alkaline phosphatase activity (AP). (C) Expression of undifferentiated cell specific markers: OCT4, REX1, NANOG and SOX2 in SZ-SMA5 and a wild-type (WT) HESC control by RT-PCR. GAPDH expression served as a loading control. (D) Teratoma sections stained by H&E from SZ-SMA5 demonstrating multi-cellular structures derived from the three different embryonic germ layers. (E) A representative normal 46(XX) karyotype in SZ-SMA5 as identified by Giemsa staining of 20 different spreads of metaphase chromosomes.