University of Hawaii Identifies L-BAM, a Treatable Form of Mesothelioma

Researchers at the University of Hawaii Cancer Center have identified a distinct, treatable form of mesothelioma driven by inherited genetic mutations rather than asbestos exposure. The variant, called low-grade BAP1-associated mesothelioma (L-BAM), responds to standard cancer therapies and can allow near-normal lifespans when detected early.

The findings, published in the Journal of Thoracic Oncology in September 2025, represent a significant shift in how the disease is understood and treated.

A Different Disease Entirely

Mesothelioma caused by asbestos exposure is aggressive and resistant to most treatments, with a median survival of six to 18 months. L-BAM is biologically distinct. It arises from inherited germline mutations in the BAP1 tumor suppressor gene and follows a far less aggressive course.

The research team, led by Drs. Michele Carbone and Haining Yang, studied families across Louisiana, Wisconsin, and Turkey before expanding to diverse populations including Native Hawaiian, Japanese, and Jewish communities. They found that L-BAM patients who received standard treatments, including surgery and chemotherapy, could achieve outcomes dramatically better than those with the asbestos-related form.

“This is not the same disease,” the researchers concluded. Where asbestos-related mesothelioma has been described as “uniformly lethal,” L-BAM is manageable with existing therapies.

Why It Matters

Approximately 3,000 people are diagnosed with mesothelioma in the United States each year, with roughly 2,500 deaths. The vast majority of cases are linked to asbestos. But a subset of patients, particularly those with no known asbestos exposure, may carry BAP1 mutations that place them in the L-BAM category.

For these patients, the distinction is life-changing. Rather than facing a prognosis measured in months, early detection through genetic testing can lead to treatment plans that extend survival significantly.

The discovery also carries implications for cancer screening more broadly. People with BAP1 mutations face elevated risks of multiple cancer types beyond mesothelioma, including melanoma, kidney cancer, breast cancer, and liver cancer. Identifying carriers early allows physicians to monitor for these associated cancers before they progress.

Genetic Testing Is Available Now

BAP1 genetic testing is currently available in the United States and abroad. The UH Cancer Center recommends testing for anyone diagnosed with mesothelioma who has no clear asbestos exposure history, as well as family members of known BAP1 mutation carriers.

The test can distinguish L-BAM from asbestos-related mesothelioma, allowing physicians to tailor treatment accordingly. For families with a history of mesothelioma or the associated cancer types, genetic counseling can identify at-risk individuals before symptoms develop.

What Comes Next

The findings have been validated in collaboration with the National Cancer Institute and presented at major institutions including MD Anderson, Memorial Sloan Kettering, and NCI. Ongoing research funded by an NCI R01 grant continues to explore personalized treatment approaches for BAP1-mutated cancers.

Several experimental therapies currently in clinical trials may prove particularly effective for L-BAM patients. These include Hippo/TEAD pathway inhibitors like VT3989 and arginine-depleting agents like pegargiminase, both of which target molecular pathways relevant to BAP1-mutated tumors.

For a disease where prognosis has historically been measured in months, the identification of a treatable variant represents a meaningful advance. The key is getting the right diagnosis through genetic testing, so patients receive the treatment approach that matches their specific form of the disease.