In the mid-1990s, inactivation of the NF2 gene wasreported in approximately 40% of all cases of MM.(39) Subsequent studies have demonstrated the importance ofNF2 inactivation in MM.(40) Although NF2 mutations have been found in 38% of casesof MPM, an absence of NF2 mutations has recently been reported innon-small cell lung cancer, this being a possible approach to the differentialdiagnosis of the two.(41) Therefore, mutations/alterations in the NF2 gene areimportant to the development of MM and currently constitute the second most commonalteration in MM. Here, NF2 is linked to small cell lung carcinoma.