The Swiss pharmaceutical and biotechnology company Roche announced the launch of the VENTANA BAP1 test on Oct. 28, 2026, releasing an automated immunohistochemical assay meant to help accurately identify the rare and aggressive cancer mesothelioma and distinguish it from other cancers.
Roche touted the assay’s global release as providing a highly specific test that can play a key role in efficiently diagnosing mesothelioma with less biopsy tissue needed, when used in conjunction with previously released VENTANA MTAP and Claudin-4 tests.
“Timely differential diagnosis of mesothelioma is critical to help deliver the best outcome for patients,” said Roche Diagnostics CEO Matt Sause in a release. “Adding BAP1 to our portfolio underscores our commitment to developing innovative solutions that enable healthcare systems around the world to address diseases with high unmet need, such as mesothelioma.”
More on the VENTANA BAP1 Test for Mesothelioma
According to Roche, the VENTANA BAP1 test, along with two other recently released VENTANA assays – MTAP and Claudin-4 tests – can help solve a problem faced by many pathologists when attempting to diagnose mesothelioma: tthe limited amount of tissue available from biopsies, that is often used up through various diagnostic tests.
The VENTANA tests help address this by testing tissue samples for very specific markers that have a high association with mesothelioma, in this case the protein BAP1. By searching for these specific markers, they help differentiate mesothelioma from benign or malignant conditions that may look similar, while preserving more tissue for other necessary tests.
The VENTANA BAP1 test is not sufficient to diagnose mesothelioma on its own, but loss of BAP1 expression can provide strong evidence supporting a malignant mesothelial process when interpreted alongside other findings.
What is BAP1?
BAP1 (BRCA-1 associated protein 1) is a tumor suppressor protein produced by the BAP1 gene. BAP1 helps control cell growth, cell division, and cell death, and helps prevent cells from becoming cancerous.
In mesothelioma, loss or mutation of BAP1 can impair the cell’s ability to repair damaged DNA, allowing genetic mistakes to accumulate and abnormal cells to survive, increasing the risk of the development of cancer.
Studies have shown that mesothelioma patients display a loss of BAP1 protein expression. Research has also identified increased EZH2 activity as one potential consequence or associated feature of BAP1-deficient mesothelioma. This imbalance leads to abnormal cell growth, slower cell death, and the accumulation of abnormal cell clusters, all of which contribute to tumor growth.
As such, being able to quickly and efficiently test for whether BAP1 protein expression is present or absent in tumor cells should be able to help healthcare providers distinguish mesothelioma from other similar cancers.
Sources & Author
- Roche strengthens cancer diagnostic portfolio with launch of test for differential diagnosis of mesothelioma. Roche Diagnostics press release. Retrieved from https://diagnostics.roche.com/us/en/news-listing/2026/cancer-mesothelioma-diagnostic-test.html
- BAP1 gene. Genetics Home Reference. Retrieved from: https://ghr.nlm.nih.gov/gene/BAP1. Accessed: 11/02/2026.
- Photo credit: Marlon Trottmann / Shutterstock.com Asset id: 1953872299. Accessed: 11/02/2026.
