Recent molecular studies have demonstrated that mesotheliomas
commonly show mutation or deletion of cyclin-dependent kinase inhibitor 2A (CDKN2A, p16) and BRCA-associated protein-1 (BAP1), and this information has been exploited through the use of p16 fluorescence in situ hybridization (FISH) analysis and BAP1 immunohistochemistry, where loss of either marker is a reliable indicator that a mesothelial proliferation is malignant.
The biphasic (mixed) subtype is the second most common histologic type accounting for 20-35% of all malignant pleural mesotheliomas
represents 30% of all mesotheliomas
 and it can be localized or diffuse.
Histologically malignant pleural mesotheliomas
(MPM) are classified as epithelial (50%), sarcomatoid (15%) & biphasic (35%).
20% to 33% of all mesotheliomas
(one fifth to one third) arise from the peritoneum.
8] The histopathologic differential diagnoses of malignant urogenital mesotheliomas
includes metastatic adenocarcinoma, papillary mesothelial hyperplasia, carcinoma of the rete testis and embryonal carcinoma.
1) Nearly 85% of all mesotheliomas
arise from the pleura, while approximately 9% arise in the peritoneum.
Inhaled asbestos fibers may contribute to three-fourths of malignant mesotheliomas
diagnosed in men and almost 40% of cases diagnosed in women.
About three-fourths of mesotheliomas
start in the chest cavity.
In fact, p53 is infrequently mutated in mesotheliomas
, (15) and what has been described as positivity for p53 in mesotheliomas
is, in retrospect, probably a mixture of a (mostly) normal and an occasional abnormal immunophenotype.
Occupational and environmental asbestos exposure may cause asbestosis (evolutive lung fibrosis), pleura/fibrosis and calcification, lung cancer, and mesotheliomas
, with a risk proportional to the duration and intensity of exposure (Antman 1993; Magnani et al.
GLUT-1 shows focal positivity in 67% of mesotheliomas
and in 3% of reactive lesions, while IMP3 shows more diffuse positivity in 73% of mesotheliomas
and negativity in reactive lesions.