THE DIAGNOSTIC IMPLICATIONS OF VARIABLE CYTOKERATIN EXPRESSION IN MESOTHELIOMAS

Immunostaining for cytokeratin has a well-established diagnostic appli cation in distinguishing sarcomatous mesotheliomas from sarcomas based on the premise that cytokeratin expression is common in mesotheliomas but very rare in sarcomas. However, the frequency of cytokeratin dete ction is highly dependent on the choice of antibody. The aim of this s tudy was to examine the distribution of simple cytokeratins and strati fied cytokeratins in 45 mesotheliomas of various types and to assess t he diagnostic utility of a simple cytokeratin antibody, a stratified c ytokeratin antibody, and a broad spectrum cytokeratin antibody with th e aim of establishing the superiority of one for routine diagnostic us e. Particular attention was paid to the potential utility of these ant ibodies in biopsy specimens. The broad spectrum cytokeratin antibody p erformed better than both the simple cytokeratin antibody (paired t-te st: P<0.01) and the stratified cytokeratin antibody (P<0.01) as a diag nostic marker of mesothelioma and should be used in preference to the other two antibodies. particularly when considering small biopsy speci mens.