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Stains

PTEN

Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 16 March 2013, last major update March 2013
Copyright: (c) 2002-2013, PathologyOutlines.com, Inc.

Definition
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● Phosphatase and tensin homologue deleted on chromosome Ten (at 10q23)
● Tumor suppressor gene commonly lost in human cancer
● Has important role in cell cycle regulation and apoptosis
● Produces a dual-specific lipid phosphatase that negatively regulates protein kinase-B/AKT activity by dephosphorylating phosphatidylinositol-triphosphate (PI3)


Diagram

Clinical features
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● Reduced PTEN expression predicts relapse in breast carcinoma patients treated with tamoxifen (Mod Pathol 2005;18:250)
● Mutations are associated with resistance to antiandrogen therapy; also Cowden’s syndrome, carcinoma of bladder, breast, endometrium (Mod Pathol 2012;25:1508), esophagus (Hum Pathol 2012 Nov 14 [Epub ahead of print]), head and neck (squamous cell carcinoma), kidney (Am J Surg Pathol 2011;35:1549), lung, prostate (Mod Pathol 2013 Jan 25 [Epub ahead of print]), stomach and thyroid; glioblastoma, melanoma
● Gross rearrangements of PTEN locus occur in prostate cancer and can be detected by a 'break-apart' FISH assay (Mod Pathol 2012;25:902)
● PTEN hamartoma tumor syndrome presents in a spectrum that encompasses Cowden and Bannayan-Riley-Ruvalcaba syndromes (Am J Surg Pathol 2012;36:671)

Uses by pathologists
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● Loss of nuclear PTEN expression in adenomatous thyroid nodules is sensitive and specific for Cowden syndrome (Am J Surg Pathol 2011;35:1505)
● Loss of cytoplasmic PTEN may distinguish intraductal prostatic carcinoma from high grade PIN (Mod Pathol 2012 Dec 7 [Epub ahead of print])

Micro images
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Breast: strong staining in benign breast epithelium; variable staining in carcinoma

 
Colon: carcinoma and adenoma


Kidney: loss of expression in clear cell carcinoma (figure D)


Liver: cholangiocarcinoma


Stomach: adenocarcinoma

 
Uterus: endometrial carcinoma

Positive staining - normal
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● Found in almost all body tissue

Positive staining - disease
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● Various carcinomas

Negative staining
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● Frequent loss of expression in carcinoma

End of Stains > PTEN

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