SMARCB1 and neoplasm: Although in mGFAP-Cre;Smarcb1flox/flox;Nf2flox/flox mice loss of Smarcb1 and Nf2 is synchronous and not sequential as postulated by the 4-hit/3-step model, this is the first tumor model reproducing the genetic profile of schwannomatosis-schwannomas with concomitant loss of both Smarcb1 and Nf2 genes, with schwannoma and no RT development (Fig. 7).