PTCH1 and medulloblastoma: To confirm this similarity, we compared the expression profiles of our tumours with a data set of non-Smarcb1-deficient tumours profiled on the same Affymetrix MOE430 arrays, consisting of Shh medulloblastomas (Mb, Ptch1+/− model, provided by O.A.)and neuroblastomas (Nb, Th-Mycn model from our laboratory14); since lymphomas from Roberts' model were not analysed on the same array, we also aimed to compare our tumours with comparable, still different, lymphomas available from public data sets (CD8(+)CD4(+) lymphomas from ref. 15).