Malignant pleural mesothelioma

Malignant mesothelioma (MM) is a rare but very aggressive tumor that arises from mesothelial cells lining the pleural, peritoneal and pericardial cavities. Malignant pleural mesothelioma (MPM) is the most common type, accounting for about 70% of all MM cases. Past asbestos exposure represents the major risk factor for MPM, as the link between asbestos fibres and MPM has been largely proved by epidemiological and experimental studies. Recently, simian virus 40 (SV40) has been implicated in the aetiology of MPM. The accumulation of numerous clonal chromosomal deletions in most MMs suggests a multistep process of tumorigenesis, characterized by the loss and/or inactivation of multiple tumor suppressor genes (TSGs). Cytogenetic and loss of heterozygosity (LOH) analyses of MMs have demonstrated frequent deletions of specific sites within chromosome arms 1p, 3p, 6q, 9p, 13q, 15q, and 22q. Furthermore, TSGs within two of these regions, i.e., p16/CDKN2A-p14ARF at 9p21 and NF2 at 22q12, are frequently altered in MMs. Mutations of the p53 gene (TP53) are occasionally observed in MMs.