SMARCB1 and neoplasm: While biallelic loss of Smarcb1 leads to early lethality during mouse development, haplo-insuffient mice are prone to develop tumors that resemble human RTs, showing loss of heterozygosity that is typical for a tumor suppressor (Klochendler-Yeivin et al. 2000; Roberts et al. 2000; Guidi et al. 2001).