Malignant mesothelioma is an uncommon kind of cancer in which fatal cancer cells enter the protective lining of the heart (pericardium), stomach (abdomen) and chest (pleura) causing a disease that in most cases is not curable. The National Cancer Institute has to say that predominantly in cases diagnosed with malignant mesothelioma, individuals have either been subject to asbestos exposure at a work place or someplace else that they spent enough time to end up inhaling asbestos fibers in large quantities. Asbestos exposure does not necessarily lead to cancerous diseases such as in the case of asbestosis but again there are high probabilities that it might give rise to a cancerous disease such as mesothelioma. The disease is often associated with a long latency period which is why workers who got affected during the 40s and 50s are getting diagnosed with mesothelioma only now, decades later.