In cases of neurofibromatosis type II, the germline variant of the congenital NF2 gene, combined with the acquired inactivation of this gene in somatic cells, leads to vestibular schwannomas, similar to the well-known “two-hit” theory for tumors caused by the inactivation of other tumor suppressor genes [110] (Figure 3). The gene discussed is NF2; the disease is neoplasm.