Tenascin-X

Tenascin-X is a member of the Tenascin family of four glycoproteins.  It is predominantly expressed in loose connective tissues including the dermis, epimysium and blood vessels.  Inactivating mutations give rise to the Ehlers Danlos syndrome.  Tenascin-X mRNA expression is higher in malignant mesothelioma than in ovarian carcinoma and primary peritoneal carcinomas, indicating that examination of the protein expression may be useful in this differential diagnosis.  

Immunohistochemical expression

Staining may be membranous or cytoplasmic.

    percentage of cells positive for Tenascin-X: 0% 1%-5% 6%-25% 26%-75% 76%-100%  
Effusions reactive mesothelial proliferation 6/91 2/91 1/91    
malignant mesothelioma 3/371 6/371 4/371 15/371 9/371
breast carcinoma 36/521 13/521 2/521 1/521  
ovarian carcinoma 42/471 4/471 1/471    
other gynaecological carcinomas 11/151 4/151      
lung carcinoma 10/121 2/121      
gastrointestinal carcinoma 6/101 4/101      
prostatic carcinoma 1/11        
Solid tumours Malignant mesothelioma 15/561 22/561 12/561 7/561  
ovarian carcinoma 122/1221        
             

Comparison with other antibodies useful in differentiating ovarian carcinoma from mesothelioma:

    Ovarian carcinoma/ primary peritoneal carcinoma Breast carcinoma Mesothelioma  
Ber-EP4 47/471 45/471 13/361
B72.3 42/471 23/471 0/361
EMA membrane only staining 0/471 0/471 33/361
EMA cytoplasmic (+/- membrane) staining 47/471 47/471 2/361
Calretinin 9/471 11/471 35/361
Tenascin-X 5/471 15/471 33/361
       

 

Diagnostic utility

References

1 Yuan Y, Nymoen DA, Stavnes HT, Rosnes AK, Bjorang O, Wu C, et al. Tenascin-X is a novel diagnostic marker of malignant mesothelioma. Am J Surg Pathol. 2009 Nov;33(11):1673-82.

This page last revised 30.4.20100.

©SMUHT/PW Bishop