Noteworthy, by immunohistochemical analysis, we also evaluated in tumors and preneoplastic lesions of Ptch1+/−/Btg1WT and Ptch1+/−/Btg1KO mice the expression of Sox2, a marker for tumor stem cells in Shh-induced MB (69), without finding any difference (data not shown). Here, SOX2 is linked to neoplasm.