SMARCB1 and neoplasm: The mutated germline SMARCB1 gene copy is retained in the tumor (hit 1), whereas chromosome 22, or at least a segment of chromosome 22 containing the wildtype SMARCB1 gene copy and a wildtype copy of the NF2 gene is lost (hits 2 and 3), followed by a mutation in the remaining wildtype NF2 gene copy (hit 4) [119,121,124] (Figure 3).