Tissue polypeptide antigen as a biological marker of malignant pleural mesothelioma

To evaluate the role of tissue polypeptide antigen (TPA) as a biological marker of malignant pleural mesothelioma (MPM), we used immunohistochemical techniques to detect TPA in tumor cells, and we measured the content of TPA in serum from patients with MPM. In 14 of 16 patients with MPM, TPA was detected in the cytoplasm of tumor cells. Epithelial-type cells from 11 of 12 patients were stained positively (91.7%), and sarcomatous-type cells from 7 of 8 patients were stained positively (87.5%). Serum TPA levels were abnormally high in 7 of 9 patients. Two of three patients with stage-I disease had normal serum TPA levels, and all patients whose disease was at stage II or higher had abnormal serum TPA levels. Serum TPA levels increased as MPM progressed. These results suggest that the serum TPA level can be used as a biological marker of MPM.