Roche strengthens cancer diagnostic portfolio with launch of test for differential diagnosis of mesothelioma

The VENTANA BAP1 (SP527) test helps confidently distinguish malignant mesothelioma from lung, breast and stomach cancers, as well as benign tissue growth in the chest or abdomen.
Most patients are diagnosed with mesothelioma late, resulting in a median overall survival of just 12 to 18 months.¹
Roche's comprehensive cancer diagnostic portfolio delivers end-to-end clinical answers across the patient journey, spanning advanced tissue diagnostics, core lab immunoassays, molecular testing and digital diagnostics.

Basel, 28 October 2026 – Roche (SIX: RO, ROP; OTCQX: RHHBY) announced today the global launch of the VENTANA BAP1 (SP527)* test. This automated, ready-to-use immunohistochemistry (IHC) assay provides a reliable, highly specific diagnostic tool to help clinicians and pathologists accurately identify mesothelioma and distinguish it from other malignancies, including non-small cell lung cancer (NSCLC). The BAP1 assay is registered as a Class I IVD with U.S. Food and Drug Administration, has received IVDR approval as a Class C device, and is available globally.

BAP1 pinpoints malignant mesothelioma, a deadly, rare cancer that forms in the tissue that lines many internal organs.² More than 80 percent of mesothelioma cases are found in the pleural cavity,³ an area of thin fluid-filled space between the two layers of tissue that surround each lung.

“Timely differential diagnosis of mesothelioma is critical to help deliver the best outcome for patients,” said Matt Sause, CEO of Roche Diagnostics. “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.”

A major challenge in lung cancer and mesothelioma diagnostics is the preservation of limited patient tissue samples. Traditional approaches can exhaust tissue blocks through extensive antibody panels. Single markers with high specificity, such as BAP1 (SP527), along with the recently launched VENTANA MTAP (SP530) and VENTANA Claudin-4 (EP417) tests, allow pathologists to accurately differentiate cancers^4,5 while minimising tissue loss. By optimising sample management, clinicians ensure sufficient tissue remains for essential molecular sequencing and precision medicine testing.⁶

Lung cancer is the leading cause of cancer death worldwide. Every year, more than 2.5 million people are diagnosed with lung cancer globally and up to 85 percent of these cases are NSCLC.⁷

Comprehensive Lung Portfolio Leadership
Roche's comprehensive lung cancer diagnostic portfolio delivers end-to-end clinical answers across the patient pathway. The portfolio spans advanced tissue diagnostics, including foundational H&E staining and high-medical-value IHC assays like ALK (D5F3), PD-L1 (SP263) and MET (SP44) to core lab immunoassays, molecular diagnostics (oncology PCR and CGP/NGS) and navify® digital software.

Launching assays like BAP1 (SP527) alongside Roche’s existing portfolio helps address unmet clinical needs and bridge diagnostic gaps to enable more effective patient management. Acting as a powerful force multiplier, BAP1 combines with the newly launched MTAP and Claudin-4 assays to help distinguish malignant mesothelioma from benign and metastatic mimics.

This comprehensive and constantly evolving portfolio empowers medical practitioners to accelerate diagnostic certainty while maximising pre-analytical sample stewardship to preserve precious patient tissue for critical downstream diagnostics like molecular sequencing.

About the VENTANA BAP1 (SP527) Assay
The VENTANA BAP1 (SP527) Rabbit Monoclonal Primary Antibody is designed for automated IHC testing to detect nuclear loss of BAP1 expression, a tumour suppressor marker located on chromosome 3p21. IHC loss of nuclear BAP1 is virtually 100% specific for malignancy in mesothelial proliferations,^8,9 making it an indispensable tool for confirming mesothelioma in conjunction with mesothelial lineage markers such as WT1 and calretinin.

About Roche
Roche (SIX: RO, ROP; OTCQX: RHHBY) is a healthcare company uniquely placed to prevent, stop and cure diseases by uniting leading science and technology across diagnostics, medicines and digital solutions.

Roche was founded in Basel, Switzerland in 1896 and today is a leading provider of transformative medicines and diagnostics for millions of people in over 150 countries around the world. It is dedicated to tackling healthcare challenges that place the greatest strain on patients, families, communities and healthcare systems. Across its Diagnostics and Pharmaceutical divisions, Roche focuses on areas including oncology, neurology, cardiovascular and metabolic diseases, ophthalmology, infectious diseases and immunology with the aim of providing real and positive change for patients, the people they love and the professionals who care for them.

Genentech in the United States is a fully owned subsidiary in the Roche Group. Roche is the majority shareholder in Chugai Pharmaceutical, a major innovator in the Japanese therapeutic antibody market.

For more information, please visit www.roche.com.

* VENTANA BAP1 (SP527) Rabbit Monoclonal Primary Antibody

All trademarks used or mentioned in this release are protected by law.

References
[1] Gunatilake S, Lodge D, Neville D, Jones T, Fogg C, Bassett P, Begum S, Kerley S, Marshall L, Glaysher S, Elliott S, Stores R, Bishop L, Chauhan A. Predicting survival in malignant pleural mesothelioma using routine clinical and laboratory characteristics. BMJ Open Respir Res. 2021 Jan;8(1):e000506. doi: 10.1136/bmjresp-2019-000506. PMID: 33414260; PMCID: PMC7797245.
[2] Syed HA, Wallen JM. Malignant Mesothelioma. [Updated 2025 Jan 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519530/
[3] CDC Incidence of Malignant Mesothelioma. Accessed at: https://www.cdc.gov/united-states-cancer-statistics/publications/mesothelioma.html on 25 August 2026.
[4] Louise Andersen Lynggård, Vasiliki Panou, Weronika Szejniuk, Oluf Dimitri Røe, Christos Meristoudis, Diagnostic capacity of BAP1 and MTAP in cytology from effusions and biopsy in mesothelioma, Journal of the American Society of Cytopathology, Volume 11, Issue 6, 2022, Pages 385-393,ISSN 2213-2945,https://doi.org/10.1016/j.jasc.2022.07.003.
[5] Bernardi L, Bizzarro T, Pironi F, Szymczuk S, Buda R, Fabbri E, Di Claudio G, Rossi G. The "Brescia panel" (Claudin-4 and BRCA-associated protein 1) in the differential diagnosis of mesotheliomas with epithelioid features versus metastatic carcinomas. Cancer Cytopathol. 2021 Apr;129(4):275-282. doi: 10.1002/cncy.22368. Epub 2020 Oct 12. PMID: 33045147.
[6] Monaco S, Mehrad M, Dacic S. Recent Advances in the Diagnosis of Malignant Mesothelioma: Focus on Approach in Challenging Cases and in Limited Tissue and Cytologic Samples. Adv Anat Pathol. 2018 Jan;25(1):24-30. doi: 10.1097/PAP.0000000000000180. PMID: 29227332.
[7]WHO Lung Cancer Fact sheet. Accessed at: https://www.who.int/news-room/fact-sheets/detail/lung-cancer on 25 August 2026.
[8]Chapel DB, Schulte JJ, Husain AN, Krausz T. Application of immunohistochemistry in diagnosis and management of malignant mesothelioma. Transl Lung Cancer Res. 2020 Feb;9(Suppl 1):S3-S27. doi: 10.21037/tlcr.2019.11.29. PMID: 32206567; PMCID: PMC7082260.
[9] Wang LM, Shi ZW, Wang JL, Lv Z, Du FB, Yang QB, Wang Y. Diagnostic accuracy of BRCA1-associated protein 1 in malignant mesothelioma: a meta-analysis. Oncotarget. 2017 Aug 17;8(40):68863-68872. doi: 10.18632/oncotarget.20317. PMID: 28978163; PMCID: PMC5620303.

Roche Global Media Relations
Phone: +41 61 688 88 88 / e-mail: media.relations@roche.com

Tristan Schmitz Phone: +41 79 529 70 35	Nathalie Altermatt Phone: +41 79 771 05 25
Lorena Corfas Phone: +41 79 568 24 95	Simon Goldsborough Phone: +44 797 32 72 915
Karsten Kleine Phone: +41 79 461 86 83	Kirti Pandey Phone: +41 79 398 38 53
Yvette Petillon Phone: +41 79 961 92 50	Irène Stephan Phone: +41 79 377 83 75
Albert Thottiyil Phone: +41 79 775 66 12

Roche Investor Relations

Dr Bruno Eschli Phone: +41 61 68-75284 e-mail: bruno.eschli@roche.com	Dr Sabine Borngräber Phone: +41 61 68-88027 e-mail: sabine.borngraeber@roche.com
Dr Birgit Masjost Phone: +41 61 68-84814 e-mail: birgit.masjost@roche.com