NCIt definition : A recombinant immunotoxin consisting of the single chain anti-mesothelin monoclonal
antibody SS1(dsFv) linked to Pseudomonas exotoxin PE-38. The monoclonal antibody moiety
of the agent binds to cells that express mesothelin, a cell surface glycoprotein which
may be overexpressed in ovarian cancer, mesotheliomas, and some squamous cell carcinomas;
after internalization, the exotoxin moiety inactivates eukaryotic translation elongation
factor 2, thereby disrupting tumor cell protein synthesis. (NCI04);