Differential diagnosis, however, is facilitated by the identification of a characteristic mesothelioma immunophenotype [14,18], expressing calretinin, CK 5/6, WT1, thrombomodulin, mesothelin, HBME-1 and podoplanin D240, features absent in cytologically similar neoplasms (in both females and males) which exhibit their characteristic markers. This evidence concerns the gene WT1 and mesothelioma.