MUC4 and malignant epithelioid mesothelioma: The sensitivity and specificity of MUC4 to differentiate epithelioid mesothelioma from lung adenocarcinoma were 100% and 83.3% respectively with the accuracy rate of 92% and those of MUC4 to differentiate epithelioid mesothelioma from lung squamous cell carcinoma 100% and 89.3% respectively with the accuracy rate of 95%.