The Xist KO mammary stem cell.

The mammary organ is considered an immunologically and anatomically privileged site. We pioneered the study of Xist in cancer and normal development. We provide here a basic description of major changes in the mammary stem cell upon deletion of Xist. We demonstrate here loss of O-6-methylguanine-DNA methyltransferase, encoded by MGMT, in the Xist KO mammary stem cell. Cellular identity and modular functionality indicated by expression of ABC transporters sheds insight into immunologic and anatomic privilege. Here, Xist deletion resulted in activation of ABCD1 and ABCG2.