Mesothelioma is best described as a form of lung cancer that attacks the lining of the lungs, also known as the mesothelium. Though rare, this form of cancer is very aggressive and those who are diagnosed with the disease rarely survive beyond a year or two from the date of diagnosis. Many die within months, as the disease is generally not diagnosed until its later stages when treatment options are few. While individuals develop certain other cancers for a number of reasons, such as poor diet or stress, there is only one known cause of mesothelioma – exposure to asbestos. Doctors estimate that in more than 85% of all mesothelioma diagnoses, they can establish a definite link to asbestos.