CK5/6 in effusions: no difference between mesothelioma and pulmonary and nonpulmonary adenocarcinoma.
OBJECTIVE: To test the performance of CK5/6 for the differentiation between mesothelioma, adenocarcinoma and benign mesothelia/proliferations in effusion cytology. STUDY DESIGN: CKS/6 immunocytochemistry was applied to ethanol-fixed cytospin preparations from 74 benign and malignant effusions. RESULTS: Reactivity was seen in 7 of 8 mesotheliomas and in 9 of 11 benign mesothelial proliferations but