Alternate Test Names:
BRCA-associated protein 1
BAP1 is a ubiquitin hydrolase and has been shown to enhance BRCA1-mediated cell growth suppression, and functions as a tumor suppressor gene. Loss of expression of BAP1 by immunohistochemistry correlates well with the presence of either BAP1 mutations or deletions at the DNA level. In a 2015 study, we have demonstrated that in the context of mesothelial lesions, BAP1 loss is 100% specific for mesothelioma, albeit with low (27%) sensitivity. However, when combined with p16 FISH a sensitivity of 58% for mesothelioma can be attained (Sheffield BS et al., Am J Surg Pathol 39:977-82, 2015).
This IHC test is clinically indicated for diagnostic purposes. Specifically, it will be used in conjunction with P16 FISH probe to separate benign from malignant mesothelial proliferations, and is particularly useful when tissue invasion by mesothelial cells cannot be demonstrated. However, combined BAP1/p16 FISH testing is not highly sensitive, and negative results do not rule out a mesothelioma.
Subcellular Localization: nuclear
CPT Code(s): 88342 or 88341
Turnaround Time: Within 1-2 business days of receipt
Schedule: Monday - Friday
• Formalin-fixed, paraffin-embedded (FFPE) tissue block or cell block - OR -
• 1 unstained slide for each test requested plus 3-4 additional unstained slides cut at 4µm