[1][12] Signs and symptoms of mesothelioma may include shortness of breath due to fluid around the lung, a swollen abdomen, chest wall pain, cough, feeling tired, and weight loss.

Other features may include weight loss, fever, night sweats, poor appetite, vomiting, constipation, and umbilical hernia.

[16] If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, trouble swallowing, or swelling of the neck or face.

[11] In severe cases of the disease, the following signs and symptoms may be present:[8] If a mesothelioma forms metastases, these most commonly involve the liver, adrenal gland, kidney, or other lung.

Environmental exposure to asbestos has caused mesothelioma in places other than Turkey, including Corsica, Greece, Cyprus, China, and California.

[citation needed] In a recent research carried on white American population in 2012, it was found that people with a germline mutation in their BAP1 gene are at higher risk of developing mesothelioma and uveal melanoma.

In Turkey, the United States, and Mexico, erionite has been associated with mesothelioma and has thus been designated a "known human carcinogen" by the US National Toxicology Program.

[22] In rare cases, mesothelioma has also been associated with irradiation of the chest or abdomen, intrapleural thorium dioxide (thorotrast) as a contrast medium, and inhalation of other fibrous silicates, such as erionite or talc.

The processes leading to the development of peritoneal mesothelioma remain unresolved, although it has been proposed that asbestos fibers from the lung are transported to the abdomen and associated organs via the lymphatic system.

This is supported by the observed recruitment of significant numbers of macrophages and other cells of the immune system to localized lesions of accumulated asbestos fibers in the pleural and peritoneal cavities of rats.

[citation needed] Experimental evidence suggests that asbestos acts as a complete carcinogen with the development of mesothelioma occurring in sequential stages of initiation and promotion.

The molecular mechanisms underlying the malignant transformation of normal mesothelial cells by asbestos fibers remain unclear despite the demonstration of its oncogenic capabilities (see next-but-one paragraph).

However, complete in vitro transformation of normal human mesothelial cells to a malignant phenotype following exposure to asbestos fibers has not yet been achieved.

[67] Asbestos fibers have been shown to alter the function and secretory properties of macrophages, ultimately creating conditions which favour the development of mesothelioma.

Following asbestos phagocytosis, macrophages generate increased amounts of hydroxyl radicals, which are normal by-products of cellular anaerobic metabolism.

While absence of malignant cells on cytology does not completely exclude mesothelioma, it makes it much more unlikely, especially if an alternative diagnosis can be made (e.g., tuberculosis, heart failure).

To obtain tissue for examination, the doctor makes a small incision in the abdomen and inserts a special instrument into the abdominal cavity.

[citation needed] Immunohistochemical studies play an important role for the pathologist in differentiating malignant mesothelioma from neoplastic mimics, such as breast or lung cancer that has metastasized to the pleura.

The US National Institute for Occupational Safety and Health maintains a recommended exposure limit of 0.1 asbestos fiber per cubic centimeter.

[70] Doctors have begun testing the Mesomark assay, which measures levels of soluble mesothelin-related proteins (SMRPs) released by mesothelioma cells.

Clinical behavior of the malignancy is affected by several factors including the continuous mesothelial surface of the pleural cavity which favors local metastasis via exfoliated cells, invasion to underlying tissue and other organs within the pleural cavity, and the extremely long latency period between asbestos exposure and development of the disease.

Delivering radiation and chemotherapy after a radical surgery has led to extended life expectancy in selected patient populations.

[78] This trial was the first to report a survival advantage from chemotherapy in malignant pleural mesothelioma, showing a statistically significant improvement in median survival from 10 months in the patients treated with cisplatin alone to 13.3 months in the group of patients treated with cisplatin in the combination with pemetrexed and who also received supplementation with folate and vitamin B12.

In February 2004, the United States Food and Drug Administration (FDA) approved pemetrexed for treatment of malignant pleural mesothelioma.

[81] In January 2009, the United States FDA approved using conventional therapies such as surgery in combination with radiation and/or chemotherapy on stage I or II Mesothelioma after research conducted by a nationwide study by Duke University concluded an almost 50 point increase in remission rates.

Nonetheless, other trials involving interferon alpha have proved more encouraging with 20% of patients experiencing a greater than 50% reduction in tumor mass combined with minimal side effects.

[citation needed] In October 2020, the FDA approved the combination of nivolumab (Opdivo) with ipilimumab (Yervoy) for the first-line treatment of adults with malignant pleural mesothelioma (MPM) that cannot be removed by surgery.

[86] Pleurectomy/decortication spares the underlying lung and is performed in patients with early stage disease when the intention is to remove all gross visible tumor (macroscopic complete resection), not simply palliation.

Incidence of malignant mesothelioma currently ranges from about 7 to 40 per 1,000,000 in industrialized Western nations, depending on the amount of asbestos exposure of the populations during the past several decades.

In 1965, an article in the British Journal of Industrial Medicine established that people who lived in the neighbourhoods of asbestos factories and mines, but did not work in them, had contracted mesothelioma.