EGF and neoplasm: Given the difficulty to obtain stable Hh-dependent MB cell lines, tumor cells from spontaneous MB of Math1-cre/PtcC/C mice were propagated as neurospheres (MB Stem-Like Cells, MB-SLCs) in EGF- and bFGF-free cultured medium to retain the characteristic of in vivo Hh-subtype MB and preventing the differentiation of GCPs62.