Evaluating the expression of caveolin-1 immunohistochemistry in differentiating malignant pleural epithelioid mesothelioma from lung adenocarcinoma

Abstract

Background To evaluate the efficacy of new marker caveolin-1 (Cav-1) in differentiating between malignant pleural mesothelioma (MPM) and lung adenocarcinoma (LAC) and to compare its results with other well-known markers used to differentiate MPM from LAC. Patients and methods This study is a retrospective one conducted on 150 cases presented with pleural and/or pulmonary lesion and diagnosed by pleural segmental resection or biopsy at Pathology Department, National Cancer Institute, Cairo University, during the period from January 2016 to December 2017. Paraffin blocks were immunostained by Cav-1 using Dakoautostainer. Sensitivity, specificity, positive and negative predictive values, and total accuracy of the marker were calculated. Results Cav-1 achieved a sensitivity of 97.1%, a specificity of 93.75%, a positive predictive value of 93.1%, and a negative predictive value of 97.4%, and total accuracy of 95.3% in the cases diagnosed as MPM. Overall, 45 (66.2%) cases showed cytoplasmic expression in more than 50% (3+) of tumor cells, 20 (29.4%) cases in 5–50% (2+), and only three (4.4%) cases in less than 5% of tumor cells (1+). No significant difference was detected in the Cav-1 expression between well-differentiated and poorly-differentiated cases of malignant mesothelioma (MM) regarding score 3+ immunostaining. Conclusion Cav-1 is an immunohistochemical marker that can be used to differentiate MPM from LAC and can be added to the panel of markers used for such purpose.