Home   Chapter Home   Jobs   Conferences   Fellowships   Books



Advertisement

Stains

Cathepsin B (CTSB)


Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 29 September 2012, last major update September 2012
Copyright: (c) 2002-2012, PathologyOutlines.com, Inc.

General
=========================================================================

● Lysosomal cysteine protease associated with focal adhesions, inhibited by cystatin C, an endogenous cysteine protease inhibitor
● Usually acts only in cell cytoplasm, but in malignant tumors is secreted extracellularly and degrades extracellular matrix so tumor cells can invade
● Highest staining at invasive edge of tumor
● Acts as effector of invasion in HER2+ breast cancer (Mol Cell 2012;45:764), inflammatory breast cancer (Breast Cancer Res 2011;13:R115), prostate cancer (Int J Cancer 2012;131:2034)
● In gliomas, radiation treatment increases cathepsin B levels, suggesting that inhibition may be useful therapy (Neuro Oncol 2012;14:745, Mol Carcinog 2012 Apr 11 [Epub ahead of print])
● Inhibition may limit breast cancer metastases (Cancer Res 2012;72:1199)

Clinical features
=========================================================================

● CSF levels increase with age (Neurol Sci 2012 Mar 23 [Epub ahead of print])
● Endosomal cathepsin B may play a functional role in activation of highly pathogenic Nipah virus (J Virol 2012;86:3736)

Uses by pathologists
=========================================================================

● Cytoplasmic stain, but intense staining may appear nuclear
● High expression is poor prognostic marker in colon carcinoma, gliomas (Hum Pathol 2005;36:1008), lung cancer (serum levels, Oncol Lett 2011;2:693)

Micro images
=========================================================================



Skin: normal

   
Breast: inflammatory carcinoma and breast cancer NOS


Colon cancer


Lung: nonsmall cell lung cancer-tumor associated macrophages


Prostate: benign and malignant


Salivary glands (minor) in patients with Sjögren's Syndrome (fig C/D)

Positive staining - normal
=========================================================================

● Bowel, prostate, skin, thyroid; some endothelial cells

Positive staining - disease
=========================================================================

● Various malignancies: breast, colon, lung, prostate carcinoma; glioma; melanoma (Pathol Res Pract 1999;195:171)

End of Stains > Cathepsin B

Ref Updated: 9/29/12


This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).