MESOTHELIOMA is a cancer of the mesothelium, the lining of the chest or the lining of the abdominal wall. Early stages are associated with few symptoms. Effective therapy does not exist. There is no exposure threshold for mesothelioma. By the time it is diagnosed, it is almost always fatal. This is suggested by the observation that family members of the asbestos-exposed workers have developed mesothelioma. Presumably cleaning the clothes of the exposed worker has exposed those individuals to asbestos dust and led to the disease. Similar to other asbestos-related diseases, mesothelioma has an extended latency period of 30 to 40 years.