E-cadherin expression is a sensitive and specific method for detection of carcinoma cells in fluid specimens

The distinction between reactive mesothelial cells and carcinoma in pleural , peritoneal, and pericardial fluids is often difficult. We and others prev iously showed that E-cadherin, an epithelial-specific adhesion protein, can be useful for this distinction In this study we tested the sensitivity and specificity of E-cadherin compared to, and in combination with, convention al cytology Sor assessment of carcinoma in fluids. Cytyc ThinPrep(TM) slide s (Marlborough, MA) from 102 sequential fluids were evaluated for E-cadheri n expression by routine immunologic techniques. No evidence of E-cadherin s taining was seen in 71 cases, while 31 showed unequivocally positive staini ng. Sensitivity and specificity were independently determined Sor E-cadheri n alone (72% and 97%. respectively), cytomorphology alone (62% and 100%, re spectively), and both together (92% and 100%, respectively). We conclude th at assessment of E-cadherin expression has sensitivity and specificity comp arable to, or better than, conventional cytomorphology. If both cytomorphol ogy and E-cadherin are used together, a definitive and correct diagnosis co uld have been made on nearly every case in this study. Diagn. Cytopathol. 2 000;22: 263-267. (C) 2000 Wiley-Liss, Inc.