Tissue polypeptide antigen production in a uterine carcinosarcoma cell line in a serum-free culture

Carcinosarcomas (malignant mixed Mullerian tumors, MMMT) of the female genital tract are uncommon neoplasms, most of which show a highly aggressive behavior. However, the biological characteristics of MMMT, especially the producibility of tumor-related substances in vitro, have yet to be clarified. Using a serum-free culture model system which was newly established from an FU-MMT-2 cell line originating from an MMMT of the human uterus, the biological and immunocytochemical characteristics of MMMT cells were examined in vitro. As a control model, the uterine fibroblasts were also cultured in the same conditions. Moreover, several tumor markers were also measured by a radioimmunoassay in the serum of five patients with MMMT. FU-MMT-2 produced and secreted tissue polypeptide antigen (TPA), a tumor marker closely related to the keratin family, under serum-free culture conditions. Moreover, TPA was also immunocytochemically demonstrated in carcinoma cells as well as sarcoma cells in FU-MMT-2. On the other hand, the uterine fibroblasts showed no detectable producibility of the substances examined in vitro. An elevation of the serum TPA levels was also detected in four of five (80%) patients with MMMT. This is the first serum-free culture study of MMMT, which appears to provide a useful model for further studies of the tumor biology in MMMT of the female genital tract. An evaluation of the serum TPA level thus appears to be useful in determining the optimum management of patients with MMMT. In addition, the demonstration of TPA in sarcoma cells of FU-MMT-2 in vitro supports both the theory of a single cell origin and the current concept of MMMT as a "metaplastic carcinoma," as substantiated in our previous study.