Malignant mesothelioma: biology, diagnosis and therapeutic approaches

Malignant mesothelioma (MM) is an aggressive neoplasm of serosal cavities, which is resistant to conventional therapy, with patient survival from presentation of <12 months. MM remains a universally fatal disease of increasing incidence worldwide. Although the main risk factor is asbestos exposure, other factors, Simian virus 40 infection and inheritance of susceptibility genes, likely play a role. Asbestos-related carcinogenic process is primarily based on the interaction between susceptibility (genetic and acquired) and exposure to carcinogenic environmental agents. Asbestos-induced carcinogenesis includes generation of reactive oxygen species, which induce DNA strand breaks and oxidant-induced base modifications to DNA. Persistent oxidative DNA damage can alter signaling cascades, gene expression, induce or arrest transcription, and increase replication errors and genomic instability. The long promotion phase observed in MM pathogenesis and the absence of early symptoms both contribute to late diagnosis of the disease. This results in delayed therapeutic intervention of patients, making the outcome of the disease very grim. There have been several developments in MM management, principally based on early detection, improved diagnosis, development of more effective therapies, and new insights into the pathobiology of the disease. Several programs have been used to screen asbestos-exposed individuals for lung and pleural disease. These programs involve annual pulmonary function tests, chest radiography and high resolution computer tomography. Blood tests make screening of target populations an attractive strategy. Many current gene and protein expression studies aim to identify clinically useful biomarkers and new therapeutic targets for improved management of MM.