Expression of Oct-4 has also been reported in human primary breast carcinomas, human breast cancer cell lines, and other types of carcinoma cell lines, suggesting that its involvement in tumourigenesis may be related to the upregulation of its downstream target genes (Jin et al, 1999; Monk and Holding, 2001; Gidekel et al, 2003; Wang et al, 2003). Here, POU5F1 is linked to breast carcinoma.