The Lgr5 intestinal stem cell signature: robust expression of proposed quiescent '+4' cell markers. by Muñoz, J, Stange, D, Schepers, A, van de Wetering, M, Koo, B, Itzkovitz, S, Volckmann, R, Kung, K, Koster, J, Radulescu, S, Myant, K, Versteeg, R, Sansom, O, van Es, J, Barker, N, van Oudenaarden, A, Mohammed, S, Heck, A, Clevers, H