[Diagnostic value of tissue polypeptide antigen in pleural effusions with malignant pleural mesothelioma].

There are no known tumor makers of malignant pleural mesothelioma. We measured the concentration of TPA in the pleural effusions from patients with malignant pleural mesothelioma and from patients with other pleural diseases, evaluate its clinical usefulness. The concentration of TPA was more than 7,000 U/l (mean: 18,600 +/- 9,867 U/l, n = 5) in all patients with malignant pleural mesothelioma, but it was less than 4,000 U/l in those with benign asbestos pleurisy and other benign pleural effusion (benign asbestos pleurisy 1,598 +/- 570, n = 5: p < 0.01, tuberculous pleurisy 1.37 +/- 759, n = 11: p < 0.01, others 2,497 +/- 2,152 n = 3: p < 0.05). The concentration of TPA in the pleural effusions was not significantly different between malignant pleural mesothelioma and lung cancer (12,287 +/- 17,070 U/l). However, in all patients with lung cancer and high TPA concentrations, cytologically malignant cells were detected in the pleural effusions. TPA was high in all five patients with malignant pleural mesothelioma, but cytologically malignant cells were detected in only one patient. Only in malignant pleural mesothelioma (not in other benign disease or in lung cancer) was the concentration of TPA more than 4,000 U/l, and no evidence of malignancy was obtained by cytological methods. These findings suggest that assessing TPA in the pleural effusion might contribute to the diagnosis of malignant pleural mesothelioma.