Basel, Switzerland — October 28, 2026
Roche, a global healthcare company operating across pharmaceuticals and diagnostics, announced the global launch of the VENTANA BAP1 (SP527) test, an automated immunohistochemistry (IHC) assay designed to help clinicians and pathologists distinguish malignant mesothelioma from other cancers and benign tissue growths. The test detects the loss of nuclear expression of BRCA1-associated protein 1 (BAP1), a tumour suppressor marker that can help identify malignancy in mesothelial tissue. Registered as a Class I in vitro diagnostic in the United States and approved as a Class C device under the European Union’s In Vitro Diagnostic Regulation (IVDR), the assay is available globally. The launch expands Roche’s cancer diagnostic portfolio and aims to support faster diagnostic clarification, particularly in challenging cases involving mesothelioma and other malignancies such as non-small cell lung cancer (NSCLC). By improving diagnostic precision while helping conserve limited tissue samples, the test may also support downstream molecular testing and personalized treatment decisions.
VENTANA BAP1 Supports More Accurate Mesothelioma Diagnosis
Malignant mesothelioma is a rare and aggressive cancer that develops in the mesothelium, the protective tissue lining many internal organs. More than 80% of cases affect the pleural cavity surrounding the lungs, according to Roche. Diagnosis can be challenging because mesothelioma may resemble metastatic cancers originating in the lung, breast or stomach, as well as non-malignant mesothelial proliferations. Many patients are diagnosed at an advanced stage, contributing to a reported median overall survival of approximately 12 to 18 months. The VENTANA BAP1 (SP527) assay is designed to detect the absence of nuclear BAP1 expression, which can provide important evidence when assessing suspected mesothelioma. Roche states that loss of nuclear BAP1 expression is highly specific for malignancy in mesothelial proliferations. The assay is intended to be interpreted alongside other diagnostic markers, including WT1 and calretinin, as part of a comprehensive pathological assessment rather than as a standalone diagnosis.
Tissue Preservation Strengthens Precision Oncology Workflows
A persistent challenge in lung cancer and mesothelioma diagnostics is the limited quantity of tissue available from patient biopsies. Traditional diagnostic workflows may require multiple antibody tests, potentially exhausting tissue samples before essential molecular analyses can be completed. Roche says highly specific markers such as BAP1 (SP527), together with its VENTANA MTAP (SP530) and VENTANA Claudin-4 (EP417) assays, can help pathologists differentiate malignant mesothelioma from benign and metastatic conditions while minimizing unnecessary tissue use. Preserving tissue is particularly important when additional molecular testing is required to identify biomarkers that may guide targeted therapies or other precision medicine approaches. BAP1 is therefore positioned as part of a broader diagnostic strategy that combines pathological evaluation with molecular profiling. The clinical value of the assay depends on its appropriate use within established diagnostic protocols and interpretation alongside a patient’s clinical and pathological findings.
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Expanded Diagnostic Portfolio Addresses Unmet Needs in Oncology
The launch adds to Roche’s broader lung cancer diagnostic portfolio, which includes tissue staining, immunohistochemistry assays such as ALK (D5F3), PD-L1 (SP263) and MET (SP44), molecular diagnostic technologies including PCR and comprehensive genomic profiling through next-generation sequencing, and navify digital solutions. Roche aims to provide diagnostic support across multiple stages of the patient journey, from initial tissue assessment and cancer classification to biomarker testing that can inform treatment selection. Lung cancer remains the leading cause of cancer-related death worldwide, with more than 2.5 million diagnoses annually and NSCLC accounting for up to 85% of cases, according to the company’s announcement. By combining BAP1 with other tissue-sparing assays and established molecular technologies, Roche seeks to improve diagnostic confidence while helping laboratories manage limited biopsy material efficiently. The global launch reflects the company’s continued investment in integrated cancer diagnostics for complex diseases with significant unmet medical needs.
Source:Roche, Press release
