TCGA's Study of Mesothelioma
What is mesothelioma?
Mesothelioma is a rare cancer that affects the thin layer of tissue that lines the chest, abdominal cavities, and most of the organs within them.1 This lining is called the mesothelium.
In the United States, there are roughly 3,000 new cases diagnosed each year. Exposure to asbestos is the main risk factor for developing this disease, and men tend to be more commonly affected— a fact that most likely correlates with men holding jobs where they are more likely to come in contact with it.1
The term “asbestos” refers to a group of fibrous minerals known for their heat and corrosion resistance that in the past, were often used in a variety of products such as insulation, tiles, patching compounds, and more.1 When disturbed, asbestos can shed many tiny airborne particles which can be unknowingly inhaled or swallowed. An individual might not develop symptoms of mesothelioma until 20 or more years after initial contact, and most people develop the disease after the age of 65.1 Additional information on mesothelioma.
TCGA's mesothelioma project was an international collaborative effort between TCGA, the Wellcome Trust Sanger Institute, and the University of Western Australia. The study was also part of an effort to characterize rare tumor types.
What have TCGA researchers learned about mesothelioma?
- Defined multiple histology-independent, prognostic subtypes of mesothelioma from an integrative analysis of 74 cases of the disease.
- Identified a novel genomic subtype accounting for about 3% of samples with:
- TP53 and SETDB1 mutations
- Genomic "near haploidization", or loss of one copy of nearly all chromosomes
- Alterations to known cancer gene BAP1, present in over half of cases studied, may affect transcription factor activity and perturb immune signaling.
- The immune checkpoint gene VISTA, strongly expressed in epithelioid mesothelioma, may be restraining anti-tumor immune responses in some cases.
1American Cancer Society. Malignant Mesothelioma Overview. Atlanta: American Cancer Society, Inc. 2012.