Nanog is a homeobox transcription factor involved in maintaining the pluripotency of embryonic stem cells by blocking cell differentiation. It also plays a role in cancer cell proliferation, epithelial-mesenchymal transition, apoptosis, and metastasis. It is expressed in stem cells, as well as in a variety of carcinomas, including those of the breast, ovary, stomach, bladder, and malignant melanomas. References: Cell Res 2007 17:42; Cancer Biol Therapy 2016 17:1.