Issues keratin

Another contentious issue concerns the aberrant expression of keratin and EMA in smooth muscle tumors. Although some authors have reported a high incidence of that phenomenon in general, with no particular reference to specific soft tissue sites,the authors experience indicates that cutaneous leiomyomas and leiomyosarcomas only rarely show the presence of epithelial markers. 

Finally, the issue of firontend purification for the collected test material is perhaps the most important aspect of sample preparation. Currently there are various methods that utilize standard separation techniques to remove most abundant proteins prior to MS, i.e., removal of some 20 high-abundance proteins and better visualization of low-abundance proteins (Sigma-Aldrich kits). However, in most cases the removal of these proteins may in fact compromise the detection of biomarkers or their partners, since in many instances, viral infection leads to overexpression of the most abundant proteins such as the actins, keratins, tubulins, cyclophilins, vimentin, and HSPs among others. Therefore, future attempts at the identification of biomarkers would have to define not only the most high- and low-abundance proteins but also their partners and possible modifications. 

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