mesothelioma is associated with BAP1 mutation

  • cancer: 1.mesothelioma
  • gene mutation: 2.BAP1

The heterozygous germline BAP1 pathogenic mutation has been associated with an increased risk for a variety of cancers including malignant mesothelioma (choice B is correct).

BAP1 is a tumor suppressor gene whose inactivation affects DNA repair and transcription, cell death, and cellular metabolism. Pathogenic BAP1 truncating germline mutations usually result in the loss of BAP1 nuclear localization, affecting DNA repair, chromatin assembly, and transcription. Nontruncating mutations of BAP1 are less likely to be pathogenic. The pathogenesis of cancers related to BAP1 mutations is poorly understood. Somatic BAP1 mutations are more common in the tumor types associated with pathogenic germline mutations, supporting a pathogenic role. Biallelic inactivation of BAP1 is seen in 60% of sporadic mesotheliomas and all of the mesotheliomas that develop in carriers of germline mutations. Loss of BAP1 nuclear immunohistochemical staining supports the presence of malignancy and separates mesothelioma from other malignancies.

Carriers of autosomal dominant pathogenic germline BAP1 mutations have a lifetime penetrance approaching 100%, with one-third developing two or more cancers. In the BAP1 cancer syndrome, 27% of cancers diagnosed are malignant mesothelioma; 24%, uveal melanoma; 17%, cutaneous melanoma; 13%, melanocytic BAP1-mutated atypical intradermal tumors; and 10%, clear cell renal cell carcinoma. Other cancers, less commonly diagnosed in the syndrome, include basal and squamous cell carcinomas of the skin, meningioma, bladder cancer, cholangiocarcinoma, and lung cancer (3%) (choices A, C, and D are incorrect). Screening for BAP1 germline mutations in families with three or more of the most common of these cancers has been recommended. First-degree relatives of those with pathogenic germline mutations should have a conversation about being genotyped. For those with a pathogenic BAP1 germline mutation, annual eye and skin examinations are recommended from 18 years of age onward. MRI of the chest, abdomen, pelvis, and breast every other year was suggested in a National Cancer Institute screening protocol.

Approximately 10% of all patients with mesothelioma and 50% of those in patients younger than 50 years have a BAP1 mutation. BAP1-related mesothelioma occurs approximately 20 years earlier than sporadic mesothelioma, has a male:female ratio of 1:1, and can occur in patients with no exposure to asbestos. Mesotheliomas in germline BAP1 mutation carriers tend to be less aggressive, with median survivals of 5 to 7 years (vs 6-24 months), and some long-term survivors have been reported without aggressive treatment. Therapies specific to individuals with mesothelioma and a germline BAP1 mutation are being evaluated.1

Footnotes

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