KRT14 and pilomatrixoma: Consistent with the human studies, in mouse, sustained activation of β-catenin in all stem cell compartments that express keratin 14 (Krt14) results in pilomatricomas and trichofolliculomas (Gat et al., 1998, Lo Celso et al., 2004, Van Mater et al., 2003, Watt and Collins, 2008), while expression of ΔNLef1 results in SG tumors (Niemann et al., 2002, Niemann et al., 2007).